Since 2003, congenital malformations have increased to account for 15% of all births in Fallujah, Iraq. Congenital heart defects have the highest incidence, followed by neural tube defects. Similar birth defects were reported in other populations exposed to war contaminants. While the causes of increased prevalence of birth defects are under investigation, we opted to release this communication to contribute to exploration of these issues. By using a questionnaire, containing residential history and activities that may have led to exposure to war contaminants, retrospective reproductive history of four polygamous Fallujah families were documented. Our findings point to sporadic, untargeted events, with different phenotypes in each family and increased recurrence. The prevalence of familial birth defects after 2003 highlights the relevance of epigenetic mechanisms and offers insights to focus research, with the aim of reducing further damage to people’s health. In Fallujah (Iraq), birth defects, with prevalence of congenital heart defects (CHD) and neural tube defects (NTD), have reached in 2010 unprecedented numbers, above the World average [The epigenetic origin of many birth defects is extensively supported by the existing literature . Neural Congenital heart defects have various phenotypes and can be compounded by different cardiac-unrelated features. Approximately 30% of CHD and tetralogy of Fallot (TOF) have been shown to be associated with wide genomic rearrangements. Only in a very small fraction of the cases investigated have cohort studies detected mutations in single genes which are putatively involved . Environmental factors are implied in the induction of most CHD phenotypes, through epigenetic mechanisms.In mice, cleft lip is caused by epistatic interactions in the context of genetic maternal effects. Cleft lip and palate inheritance patterns suggest that the causes are combinations of genetic and nongenetic factors. Also in mice, synpolydactyly is linked to Hoxd13 mutations and its manifestation is dependent upon environmental factors.in-utero by epigenetic modifiers. Transplacental effector-molecules and epigenetic trans-generational mechanisms are implied in the manifestation of infant leukemia.Tumorigenesis is a multistep process involving mutations and epigenetic changes . RepeateThus, although in teratogenesis and infant leukemia can occur through genomic rearrangements or concurrence of multiple single mutational events, they are most often described and understood to be due to pleiotropic epigenetic changes which affect more than one function, or to a combination of these three mechanisms.Many known war contaminants have the potential to interfere with normal embryonic and fetal development. The devastating reproductive health effects of dioxins (the major contaminant of Agent Orange) on the Vietnamese people is well known. Data is also accumulating on increased rates of reproductive diseases in veterans of U.S. and U.K. wars during the last 20 years. As environmental effectors, metals are potential good candidates to cause birth defects. Metals are also integral to modern “augmented” and “targeted” weapons . Metals,The analysis of four cases of fathers with two lineages of progeny is presented here. In each case, we discuss what can be deduced from the family’s reproductive history, from the phenotypes of their offspring and from the modality of birth defects’ chronological occurrence. We discuss the compatibility of occurrence of birth defects with the actions of potential effectors, with the demographic of the families, and with the exposure of the parents to war-related events. We have put our evaluation into the context of mechanisms of actions for teratogens. The timing of presentation of birth defects in these families shows that they mostly occurred after 2003.ad hoc questionnaire to collect the retrospective reproductive history of families that had come to Fallujah General Hospital for childbirth and treatment. Questions about history of residence, demographic characteristics and lifestyle habits of the parents, and activities that may have led to their exposure to war-contaminants, were included.We developed an Data from four polygamous families are presented. Mothers were admitted to Fallujah General Hospital between April 2008 and May 2010 for childbirth. The data shows that each was stably resident, in different areas of the town up to 2009–2010, none of the parents were directly wounded or trapped under rubble and that, among them, only the male parent in Family 1 reported acute symptoms immediately after bombings. There is no obvious relationship to immediately adjacent bombing/burning of their houses or to the activity of cleaning/recovery of injured-dead people or to personal acute symptoms with them having a child with birth defect in the following years. This suggests that the birth defect in these families might not be due directly to acute exposure, but could be associated to their long term exposure and body accumulation of toxicants which are persistent in the environment.More efficaciously than chromosomal mutations or than multiple single gene mutations, epigenetic changes  can account for the patterns and diversity of malformation which we see in families 107, 139 and 1. Epigenetic effectors can produce simultaneously different damages and multiple phenotypes, which vary depending on the specific agent(s), and on the timing and level of exposure during embryonic life. This possibility, per se, would fit the data. The novel presentation of sporadic and diverse birth defects, which can be caused uniquely or in composite fashion by epigenetic events, also suggest that agents capable of initiating these changes are still present in the environment and continue to induce novel effects.Teratogens in the postwar environment include metals and metal alloys which persist in the environment and in the body, and are potential risks to health . Metals are involved in regulating genome stability, in X chromosome inactivation, in gene imprinting, and in reprogramming gene expression. They act as metalloestrogens, inhibit DNA repair, alter DNA methylation, change transcriptome and microRNAs production, histone acetylation and methylation; all of which can lead to birth defects, whether translated into mutations or not . As a coContinuing exposure to environmental effectors could also explain the unusually high frequency of recurrence of anencephaly and infant leukemia in a genetically-prone context (Family 123 and Family 1). These phenotypes are indeed known to derive from concomitant genetic predisposition  and from epigenetic effects due to the external environment.et al. offered a review of epidemiological studies on the teratogenicity of DU and concludes that human epidemiological evidence is consistent with increased risk of birth defects in the offspring of persons exposed to this war contaminant [Frequent miscarriages in several women during the last years are also indicative of a general negative (teratogenic) load from the environment. Epidemiological evidence on birth defects which are caused by war contaminants is common in the literature. Hindin taminant . Studiestaminant .The family history questionnaire which we developed filled serious gaps in a long history of inadequacies of the health system in Iraq. It has allowed us to begin interpretation of the facts. The strong indication of our data, that epigenetic mechanisms are at the root of the recurrence of birth defects in Fallujah, offers the hope to develop therapeutic interventions for severely affected families. Our findings can lead to a deeper understanding of the effects of war contaminants , can help elucidate causes and mechanisms that have culminated in such high rates of birth defects in Fallujah, and can open the way to intervention, both regarding immediate counseling and in terms of therapeutic intervention.We conclude that the high prevalence of birth defects in Fallujah is impairing the population’s health and its capacity to care for the surviving children. These defects could be due to environmental contaminants which are known components of modern weaponry. Investigations of metal contaminants, and elucidation of the types and body burden of metals, combined with simultaneous registry of the population’s reproductive history, will allow the identification of families at high risk and will facilitate therapeutic measures to remediate the damages.


A growing literature suggests that low birth weight increases the risk of poor health outcomes in adulthood. We tested this hypothesis among young adults living in São Paulo State, Brazil.To identify the effects of low birth weight on young adulthood outcomes, a medical assessment of 297 individuals born between 1977 and 1989 was conducted at a primary care unit in São Paulo State, Brazil. We analyzed body mass index (BMI), waist-hip ratio, blood pressure, fasting glucose and total cholesterol levels using linear and logistic regressions. Low birth was negatively associated with BMI , fasting glucose levels , waist-hip ratio , systolic blood pressure , and total cholesterol levels . Low birth weight was also associated with lower odds of young adults being overweight and obese, but neither association was statistically significant. Weight gain in the first 12 months of life was associated with higher adult BMI  and blood pressure . No associations were found between low birth weight and early life (catch-up) growth.Low birth weight was not associated with poor health outcomes among young adults in Brazil. These results appear inconsistent with the original Barker hypothesis, but will need to be corroborated in larger samples with longer follow-ups to allow a more general evaluation of the validity of the hypothesis in low and middle income countries. Following the Barker hypothesis, a large and growing literature has investigated the associations between low birth weight and adult health. According to the Barker hypothesis A large number of studies have postulated a negative theoretical link from low intrauterine growth restrictions to later life growth in the vein of the original work by Barker Few studies have analyzed the relationship between low birth weight and cardiovascular risk factors beyond basic anthropometric measures in a developing country context. One of the best non-developed country studies is the Pelotas cohort study in Southern Brazil All participants signed a written consent form. The consent form model, as well as the study were approved by the University of São Paulo Medical School's internal review board, on 10/22/2008, process number 0785/08E.We analyzed data collected through the Centro de Saúde Escola Butantã (CSEB) located in the western region of São Paulo Municipality. The CSEB is one of fourteen primary care units in the western region, covering a population of approximately 40,000 individuals. The total population of the western region is about 377,000, which corresponds to about 4% of the population of São Paulo municipality, which is currently estimated at 11.3 Million. With a crude birth rate of 15.2 and an infant mortality rate of 17 per 1000 live births, the western region is very close to the national average of Brazil with respect to population health and age structure. Over the past decades, both the region and the country have made remarkable progress with respect to population health, with infant mortality dropping from 46 deaths per 1000 in 1990 to 17 deaths per 1000 in 2009 at the national level The first records collected at the center date from 1977; the latest records considered for the study were children born in 1989. Complete birth records (paper files) could be located for 632 individuals registered with the CSEB. All 632 individuals were invited to participate in one of three assessment sessions; 297 (47%) took up the offer and were interviewed and medically assessed at the CSEB between 2008 and 2010. During the assessment, physical examinations were conducted to measure height, weight, blood pressure, heart rate, a standard battery of cholesterol measures  cholesterol, high-density lipoproteins (HDL) cholesterol, and triglycerides) as well as standard blood glucose measures. Individuals also completed a short follow-up questionnaire collecting information regarding their educational level, wealth and income. Information on birth conditions as well as weight and height over the first two years of life was extracted from the patient’s medical records.Following Yusuf et al. Empirical analysis was divided into three parts. Given the relatively high attrition rates, we used weight and gender data available from the original birth records to investigate whether patterns of study participation. In the second part, descriptive statistics were computed by study group; last multivariate analysis was conducted using basic linear regression models. For the multivariate analysis, both continuous and binary outcome measures were considered. Separate models were estimated to investigate the effects of physical growth in the first 12 months of children’s life on adult health outcomes.All analysis was conducted using the Stata © 11 statistical software package.Given that only subjects registered with the health care unit were eligible for the study, a large majority (71%) of study participants was female. Most participants completed some secondary schooling (11 years), with only 17.2% of respondents completing higher education. The average BMI in the sample is close to 25, and the average wage-to-hip ratio is 0.85. About 11% of the population has total cholesterol levels above 200 mg/dL, and only 1% of the subjects display elevated glucose levels. Using the international BMI standards, 29.9% of respondents would be classified as overweight, while 13.5% of respondents were classified as obese.The results presented in the previous section suggest that low birth weight is not associated with adverse cardiovascular risk profile during young adulthood, with indications that they may be even protective. The protective effects appear to be particularly strong for BMI. While this result is consistent with previous evidence based on the Pelotas study in Brazil One important difference between the cohort analyzed and a majority of existing studies including the Pelotas study While the presented study has only limited power to investigate interactions between intrauterine growth restrictions, the results found in this study suggest that a combination of intrauterine growth restrictions with fast early life growth  may be harmful for children’s physical development; this is consistent with a more recent generation of thrifty phenotype models outlined in Wells Apart from the small sample size, the study design has several important limitations. First, while detailed information on subjects’ education, income and living conditions was collected, no information on parental background is available. A large literature has documented the positive association between parental socioeconomic status and birth weight This directly links to a second limitation of the study. While the lower levels of fasting glucose and total cholesterol among the low birth weight group could be interpreted as evidence of better nutrition in this subgroup, no data was collected on actual calorie intake. Therefore, the available data does not allow us to distinguish nutrition behavior from genetic or metabolic differences.Third, given that participating in the study required visiting the health center on specific dates, only about half of the targeted subjects were able to participate in the study. While we did not find any systematic differences with respect to sex and birth weight, participating subjects may differ with respect to other dimensions not related to low birth weight; it is not clear, however, which variables would fall under this category, and how they would affect the estimated coefficients.The small area covered by the sample clearly also raises the question of how representative the results presented are for the country or region. As discussed in the earlier sections of this paper, the area analyzed is representative of the larger São Paulo region, which accounts for about 15% of the national population, and for about 20% of the urban population – according to the latest estimates, 87% of the Brazilian population lives in urban areas. Relative to the other states, average incomes and educational attainment in São Paulo are undoubtedly higher Last, and most importantly, the evidence presented does not allow to directly measure the later life health differentials observed in Barker’s original work Despite these important limitations, the results presented in the paper represent an important contribution to the literature testing the validity of the Barker hypothesis in low and middle income country settings. The lacking association between low birth weight and adverse early adulthood outcomes found in this paper corroborates previous findings from similar settings


During the last decade, evidence collected in cognitive, developmental, and comparative research showed that adults prevented from verbal counting, along with infants and non-human animals possess numerical systems that are independent of language . Interestingly very similar results were reported among mammals, birds, and fish, leading some authors to believe in the existence of the same numerical systems shared among vertebrates . After all, the potential implications of these works could not be underestimated by neuroscientists: the very idea that higher-level cortical mechanisms are a sine qua non condition for number processing is at risk. The study by Stoianov and Zorzi , which iThe idea that numerosity estimation can spontaneously emerge as a statistical property aligns with a previous study on adult humans which suggests that the ability to estimate the number of items might be a sort of primary visual property of stimuli, such as color and contrast, that is based on a low-level mechanism (Burr and Ross, These results may also have implications in the theoretical debate that surrounds non-verbal estimation of other magnitudes, such as time and space. According to Walsh , time, sOf course, the model created by Stoianov and Zorzi  also neeOne thing is certain: the study by Stoianov and Zorzi  now paveWe can only speculate about this latter point, but at least the lesson we can currently draw is clear: 35 units can spontaneously learn how to extract numerical information. This is enough even for simpler organisms than those reported in the literature. The last decade of comparative psychology was characterized by the discovery of numerical abilities in almost all vertebrate species. In light of the conclusions of Stoianov and Zorzi , we must


Socioeconomic status (SES) has been shown to be an important contributor to lung function. The aim of this study was to evaluate the association between lung function in adolescence and (a) SES at birth; (b) SES in adolescence; (c) SES trajectory from birth to adolescence . Additionally, we investigate the role of adolescent and parental variables at mediating these associations.Prospective birth cohort study in Pelotas, Brazil, including 4,005 adolescents (mean age: 14.7 years) followed up from birth. Lung function was measured by spirometry. Outcome variables were forced expiratory volume in one second in liters (FEV1) and forced vital capacity also in liters (FVC).Mean FEV1 was 3.46 L (95%CI 3.43-3.49) among boys and 2.93 L (95%CI 2.91-2.95) among girls. Mean FVC was 4.00 L  among boys and 3.30 L  among girls. SES at birth, in adolescence and its trajectory from birth to adolescence were inversely associated with lung function in both adolescent boys and girls. After adjustment for mediating variables, coefficients were largely reduced, particularly among boys, and the main predictor of change in coefficients was the inclusion of height in the models.Low income adolescents from Brazil present impaired lung function as compared to the better off, and this is largely explained by height. Socioeconomic status (SES) has been shown to be an important contributor to lung function. In a systematic review of articles published over the past 20 years, Hegewald and Crapo showed that poverty in adults was related to a reduction of > 300 mL in forced expired volume in one second FEV1) among men and > 200 mL among women [ among meMost prospective studies in the field have evaluated the roles of birthweight and respiratory infections in infancy and childhood on later lung function . Those aThe aims of this article were to evaluate the association between lung function in adolescence, expressed by FEV1 and forced vital capacity (FVC), and (a) socioeconomic status at birth; (b) socioeconomic status in adolescence; (c) socioeconomic trajectory from birth to adolescence. Additionally, we investigate the role of sociodemographic, anthropometric, behavioral and parental variables at mediating these associations.All hospital-born children in 1993 N = 5,265) residents in the city of Pelotas, Southern Brazil were eligible for a birth cohort study; there were only 16 refusals ,5. At th,265 resiEasy-One2; NDD Medical Technologies, Chelmsford MA, USA and Zurich, Swizerland) was used. Exclusion criteria for spirometry included a positive answer for any of the following questions in the last three months: thoracic or abdominal surgery, heart problem, eye surgery and admission to hospital for any cardiac condition; pregnancy among the girls was also exclusion for spirometry. By using these exclusion criteria, 64 adolescents were ineligible to perform spirometry. Adolescents performed as many forced expiratory maneuvers as needed in order to produce three acceptable and repeatable. Over 90% of all spirometric tests fulfilled the 2005 American Thoracic Society-European Respiratory Society quality criteria [Pulmonary function was evaluated with the adolescents seated, using a noseclip and a disposable mouthpiece. A portable, battery-operated, ultrasound transit-time based spirometer (Outcome variables were forced expiratory volume in one second in liters (FEV1) and forced vital capacity also in liters (FVC). Socioeconomic level was based on family income collected at birth and at 14-15 years of age, and was categorized in tertiles for the analyses. Mean family income at the 15 years follow up visit was around U$ 200 for the lowest tertile, U$ 500 for the intermediate tertile and U$ 1500 for the wealthiest tertile. Mean income in Pelotas is slightly higher than the national average. However, because Brazil is a big country with important income inequalities, the mean family income in Pelotas is much lower than that of the wealthiest cities in the South and Southeast regions, but much higher than that of most cities of the Northeast and North regions.Socioeconomic trajectories were created based on the combination of socioeconomic levels at birth and at 14-15 years of age. Adolescents who were classified in the lowest tertile in both periods were categorized as 'always poor'. Those who were classified in the lowest tertile at birth, but in the intermediate or top tertile at 14-15 years of age were categorized as 'poor, non-poor". Similarly, those classified in the intermediate or top tertile at birth and at the bottom tertile at 14-15 years were categorized as "non-poor, poor". Finally, those classified in both visits in the top tertile were categorized as "never poor". Family income at birth and at 14-15 years of age was measured in the same way at these two data collection points and it was based on parental report.The mediating variables included in this paper were: height at 14-15 years , weight at 14-15 years , adolescent skin color , pubertal stage by Tanner stages , medicalPrior to data collection, standardization sessions for the anthropometric measurements were carried out. These sessions were repeated every two months during the fieldwork. Reported measurement errors from the National Center for Health Statistics were used as the acceptable limits in these standardization sessions. Approximately 10% of the interviewees were re-visited by a field supervisor one or two weeks after the original interview, and a short version of the entire questionnaire was administered for quality control purposes.StataCorp, College Station, Texas, USA). Descriptive analyses included calculation of means and standard deviations for pulmonary function parameters stratified by sex. In the unadjusted analysis, simple linear regression was used to compare FEV1 and FVC according to socioeconomic variables. Multivariable analyses included linear regression using two different models. Model one included current age, height and weight separated for each gender. Model 2 added to model 1 adjustment by parental (smoking and wheezing) and adolescent variables .Data were analyzed using Stata 10.0 . The order in which mediating variables were included in the model was defined by the significance of its association with lung function. Significance level was set at 5% for two-tailed tests.Further details on the methodology of the 1993 Pelotas (Brazil) birth cohort study can be found elsewhere ,5. All pThe original cohort included 5,249 children born in 1993 in Pelotas, Brazil. From birth to 14-15 years of age, 148 cohort members were known to have died. We interviewed 4,325 adolescents, thus totaling a response rate of 85.7%. Out of the 4,325 subjects located, 4,005 provided valid spirometric data. The mean age at follow-up was 14.7 years (SD = 0.3); 51% of them were female, 64% self-rated their skin color as white, 27% were overweight, 12% reported wheezing in the past year, 39% presented medical diagnosis of rhinitis or eczema, and 19% reported to have ever smoked. Exactly half of them had at least one parent who was current smoker, and 34% of parents referred to present asthma. Mean body weight and height were, respectively, 57.4 kg (SD = 12.7) and 163.2 cm (SD = 8.2).The mean FEV1 for the whole sample was 3.19 l (95%CI 3.17-3.21), being 3.46 l (95%CI 3.43-3.49) among boys and 2.93 l (95%CI 2.91-2.95) among girls. Mean FVC was 3.65 l (95%CI 3.62-3.66), being higher among boys  than girls . Lung function was directly associated with socioeconomic status at birth and at 15 years of age. Particularly among boys, trajectories of socioeconomic status were also related to lung function. Boys who were always poor had, on average, 0.31 l lower FEV1 as compared to those who were never poor; FVC among them was, on average, 0.37 l lower than the values for those who were never poor. Equivalent values for girls were 0.18 l and 0.17 l, respectively , all associations with socioeconomic-related variables lost statistical significance. Among girls, socioeconomic status at birth and socioeconomic trajectories lost statistical significance, whereas socioeconomic level at 14-15 years of age remained statistically significant  of the models was consistently lower than those observed among boys. Third, the association between SES and lung function remained statistically significant even after inclusion of all mediating variables in the model. In spite of these differences, the R2 in the model with height only (29.5%) was just slightly different from the one obtained by the full model (34.9%).In table The association between SES and lung function is still inconclusive, in spite of several studies from various countries. It is possible that lung function reflects the effects of early life exposures that influence lung growth and development. A reduced supply of nutrients to the fetus may result in low birth weight and, depending on the timing, may result in specific detrimental effects to growing organs such as the lungs. Maternal smoking during pregnancy and maternal nutrition throughout life course may be also affect lung development. Postnatal factors such as acute respiratory infections, morbidities (e.g. asthma) and smoking during adolescence are possible determinants of lung function. Although all these factors are related to socioeconomic status, the most plausible explanation for an association between low socioeconomic status and poor lung function is multifactorial.SES at birth, in adolescence and its trajectory from birth to adolescence were inversely associated with lung function in both adolescent boys and girls in our paper. After adjustment for mediating variables, coefficients were largely reduced, particularly among boys, and the main predictor of change in coefficients was the inclusion of height in the models. Therefore, an important fraction of the SES differentials in lung function is explained by height, which is in accordance with one of the postulated factors associated with lower SES that affect lung function: poor nutrition .Lawlor and colleagues reported that poverty was associated with a reduction of 160 mL in FEV1 and 110 mL in FVC among older adults aged 60-79 years of age in the United Kingdom [Our study adds to the current knowledge in several aspects. First, we show that SES trajectories do matter in terms of later lung function. As compared to subjects who changed their SES position over time, those who were 'never poor' or 'always poor' consistently presented the highest and lowest lung function results, respectively. Second, we present the first low and middle-income prospective data on this association. Third, we explore the reasons why low income individuals present impaired lung function and most of the association with SES is explained by lower height. That is, lower income individuals are shorter (mean height: 161.2 ± 7.9 cm) than those with higher income (mean height: 164.6 ± 8.3 cm), and likewise smaller lungs that are in general terms proportional to the body size.Among boys, the anthropometric effect was so strong that incorporation of height and weight in the model completely removed the SES differentials in lung function. Among girls, although a similar pattern was observed and thus a marked reduction in the coefficients was seen, the association with SES remained statistically significant even in the model with 11 different predictors, suggesting a more complex impact of SES on lung function involving body size, composition, and other factors.Some methodological aspects of our study need to be discussed. A possible limitation is that SES groups were defined on the basis of family income, and a certain degree of misclassification is expected because of the difficulties at collecting income data. Another limitation is that data on smoking, a well known determinant of lung function, was collected by means of self-report, and we have previously shown that in early adolescence, self-reported data on smoking presents poor agreement with cotinine measurements . The useIn summary, low income adolescents from Brazil present impaired lung function as compared to the better off, and this is largely explained by height. Similar studies in other cohorts are needed to confirm our findings. Nutritional interventions targeting low income individuals may have a long-term positive impact on lung function .BMI: body mass index; CI: confidence interval; FEV1: Forced expiratory volume in one second in liters; FVC: Forced vital capacity also in liters; R²: coefficient of determination; SD: standard deviation; SES: Socioeconomic statusThe authors declare that they have no competing interests.AMBM, SCD, RPP and PCH participated in all phases of the study ; RBN and CLPA contributed with the acquisition of the data or the analysis and interpretation of such information; FCW and JMM provided substantial involvement in its revision prior to submission. Dr. AMB Menezes is the guarantor of the paper. All authors contributed to early drafts of this manuscript and approved its final version.The pre-publication history for this paper can be accessed here:http://www.biomedcentral.com/1471-2458/11/596/prepub


The current recommendation of giving the first dose of hepatitis B vaccine to very low birth weight (VLBW) infants at 30 days of chronologic age usually is not practical, because most VLBW infants are not medically stable at that age. We use an alternative body-weight-based protocol, and evaluate its efficacy in an endemic area under a universal immunization program.The immunogenicity of the current hepatitis B vaccination strategy in 155 VLBW preterm infants was evaluated at age 2 to 13 years, with parental consent. All of the infants were born between 1995 and 2006, and received their first dose of hepatitis B vaccine when they reached 2,000–2,200 g, irrespective of chronological age. Hepatitis B immunoglobulin (HBIG) was given at birth to infants born to HBsAg(+)/HBeAg(+) mothers.All 155 of the recruited children were HBsAg and anti-HBc negative. The anti-HBs seropositivity rate (geometric mean titer) was 84.1% (146.5 mIU/mL) for children under 3 years, 73.5% (68.8 mIU/mL) for 4- to 7-year-olds, 27.7% (55.4 mIU/mL) for 8- to 11-year-olds and 20% (6.0 mIU/mL) for children ≥12 years of age. More than 90% of these children received the first vaccination after 30 days of age, half (51%) at 60 to 90 days, and 29 children (18.6%) after 90 days of age. Of the 26 infants born to HBsAg(+) mothers, 6/6 infants of HBeAg(+) mothers received HBIG at birth, and 12/20 infants of HBeAg(−) mothers received HBIG. None of the 26 infants became infected.Delaying hepatitis B vaccinations in VLBW preterm infants until they reach a weight of 2,000 g, with the administration of HBIG at birth for infants of HBsAg(+) mothers provided adequate immunogenicity and protection in a highly endemic area. Weight-based policy of hepatitis B vaccination is an effective and practical alternative strategy for VLBW infants. Hepatitis B virus (HBV) infection persists as a major global health problem. More than 350 million people are chronically infected, and approximately 15 to 40% of them develop serious complications, such as cirrhosis, hepatic failure, or hepatocellular carcinoma. In endemic areas, such as Taiwan, the HBV carrier rate in the adult population reaches as high as 10–20%, and the major route of transmission is from mothers to infants. Combined administration of hepatitis B immunoglobulin (HBIG) and HBV vaccine after birth can prevent both vertical (mother-to-infant) and horizontal transmission of HBV The above-mentioned vaccination program has been based on studies in term babies, and may not be suitable for very low birth weight (VLBW) infants with birth weight below 1500 g, because of their weaker immune response. Data on the efficacy and safety of HBV vaccination in VLBW infants is limited. Recommendations for VLBW infants in different countries are based either on small-scale studies or on expert opinion. Several studies have confirmed that hepatitis B surface antibody (anti-HBs) seroconversion rates are not satisfactory in preterm infants when the vaccine is given at birth or before the infant reaches a weight of 2,000 g However, these recommendations are not clinically practical for VLBW preterm infants, because most of them are not medically stable or have not achieved steady weight gain by 30 days of chronologic age. This raises concerns regarding safety and immunogenicity related to early vaccination. For the preterm infants who are still medically unstable at 1 month of age, the timing of the first dose of hepatitis B vaccine is not established, and may be missed or delayed, which may cause practical problems for clinical staff. Furthermore, there are no follow-up data to support long-term protection of VLBW infants receiving HBV vaccinations at a time when body weight is inadequate. Because there have been increasing numbers of VLBW infants in recent years, evidence-based data are required for optimization of the immunization schedule for VLBW infants.A universal hepatitis B vaccination program was launched in July 1984 in Taiwan, one of the earliest in the world. In this program, all pregnant women are screened for serum HBsAg and HBeAg prenatally, and all infants receive three doses of HBV vaccine, at birth and at 1 and 6 months of age. In addition, infants of HBsAg- and HBeAg-positive mothers receive 0.5 ml of HBIG within 24 hours of birth. The current hepatitis B vaccination policy for preterm infants is weight-based, as per the earlier recommendation of the AAP This is a retrospective cross-sectional study approved by Institutional Review Board of the National Taiwan University Hospital. A total of 630 surviving preterm infants with birth weights <1,500 g who were admitted to National Taiwan University Hospital between 1995 and 2006 were eligible for inclusion in this study. Six hundred and one children were invited to join the study by mail, and 29 infants were excluded due to invalid addresses. All of the subjects whose parents responded were recruited in 2008, when their chronological age was >2 years. After informed-consent forms were signed by the parents of the enrolled children, 3–8 mL of blood was obtained from each child via venipuncture. The children’s immunization records, including the dates of each vaccine and HBIG, were confirmed by hospital charts and by immunization records in the official child health booklets kept by the parents. The following information was obtained from medical chart review at enrollment: gestational age, birth weight, birth length, birth head circumference, gender, delivery mode, Apgar score, HBIG administration, and length of neonatal care unit and hospital stay. The results are expressed as the mean±SD or numbers of infants and percentage of the total.All healthy, full-term newborns received three doses of recombinant HBV vaccine, Engerix-B  or H-B-Vax II  at first day, 1 month, and 6 months of age. In addition, HBIG 0.5 mL (100 IU) was given within 24 hours after birth to newborns of HBsAg-carrier mothers with positive HBeAg or high HBsAg titers . The hepatitis B vaccination policy for preterm infants is nearly the same as for full-term newborns, except for the delay of the first dose. Before Jan 2005, the first dose was administered once the infant’s body weight exceeded 2,200 g. The body-weight requirement for the first vaccination was adjusted to 2,000 g in Jan 2005. Two subsequent doses are administered 1 month and 6 months after the first vaccination. Because of preterm delivery (prior to 32 weeks), not all mothers of VLBW infants had been screened for HBsAg and HBeAg. If the maternal HBsAg carrier status was unknown within 24 hours after delivery, the staff recommended HBIG administration, but the final decision was left to the parents.Serum HBsAg and its antibody (anti-HBs) and hepatitis B core antibody (anti-HBc) were tested in all subjects. All HBV serologic markers were determined by enzyme immunoassay . Anti-HBs is considered seropositive if the titer is >10 mIU/mL. The results were presented as the rate of seropositivity or geometric mean titer with 95% confidence interval.The data was expressed as the mean±standard deviation (SD) or number of infants with percentage.A total of 155 children, who were born between 1995 and 2006 and aged 2–13 years in 2008, were recruited with parental consent . The totThe HBV vaccination schedule was delayed, based-on weight criteria in our study population. Because of the change of the government policy in 2005, all the children in the <3 years group (n = 44) received the first dose of HBV vaccination when their body weights exceeded 2,000 g. The other children in this study (n = 111) had received their first HBV vaccination when the body weight exceeded 2,200 g. The different policy made the children in the <3 years group received earlier vaccination program than the other age groups >3 years old  is comparable to that of children born at term after universal vaccination began in Taiwan (0.9%), and is much lower than the rate among children born before the vaccination program began (10%) According to AAP recommendations, early initiation of HBV immunizations at 1 month of chronologic age provides timely protection to vulnerable preterm infants, who are more likely than other children to receive transfusions or surgical interventions. The theoretical risk of horizontal transmission of infection from health-care providers, family members, and caretakers also would be minimized; however, the weight-based policy in the present study did not actually increase the risk of HBV infection. In addition to the protective effect of HBIG at birth, advances in NICU care for preterm infants may be important factors. For example, infection control measures, such as hand washing, aseptic technique, and limited visitors during NICU hospitalization may minimize HBV exposure and decrease the risk of infection in preterm infants. Of note is that there has been no restriction of HBV-carrier health-care workers in the NICU in Taiwan. Advanced screening of donor blood before transfusion also contributes to the low infection rate. Furthermore, some VLBW infants, especially those who are very preterm, are not medically stable at 1 month of chronologic age, and are not suitable for vaccination. The timing to initiate hepatitis B vaccination in these cases is uncertain, and the first dose may then be missed or more delayed. Delaying hepatitis B vaccinations in VLBW preterm infants until they reach a weight of 2,000 g is a practical strategy for clinical health providers, because by the time preterm infants reach this goal, most are medically stable, have achieved adequate muscle mass, and are suitable for vaccination.Another important finding in the present study is the high anti-HBs seroprotection rate in preterm infants under the weight-based vaccination policy. The major concern of early HBV vaccination in preterm infants is the lower rate of seroprotection and lower rate of antibody persistence. In one Alaskan study with an age-based policy, 37 preterm infants had their first HBV vaccination at a mean age of 7 days, and their seroconversion rate was only 8.1% at 3 years of age Although early HBV immunogenicity in premature infants has been studied, the data for long-term efficacy is limited. Only one study evaluated the immune response of 16 former extremely preterm infants at 7 years of age, and the reported anti-HBs seropositive rate was 86% Universal screening of pregnant women for hepatitis B and passive immunization with HBIG are highly effective measures for prevention of HBV in children born to carrier mothers Delaying hepatitis B vaccination in VLBW preterm infants until they weigh 2,000 g, a weight-based policy, provides adequate immunogenicity in an HBV endemic area. Adequate long-term seropositivity rates and geometric mean titers of anti-HBs in these infants were comparable to those of term infants. No evidence of horizontal transmission of infection was noted up to the age of 13 years. In addition, for VLBW infants born to mothers who are seropositive for both HBeAg and HBsAg, HBIG should be given to the infants immediately after birth for early protection prior to the HBV vaccination.


This study examined parenting as a function of child medical risks at birth and parental genotype . Our hypothesis was that the relation between child risks and later maternal sensitivity would depend on the presence/absence of a genetic variant in the mothers, thus revealing a gene by environment interaction (GXE). Risk at birth was defined by combining risk indices of children's gestational age at birth, birth weight, and admission to the neonatal intensive care unit. The DRD4-III 7-repeat allele was chosen as a relevant genotype as it was recently shown to moderate the effect of environmental stress on parental sensitivity. Mothers of 104 twin pairs provided DNA samples and were observed with their children in a laboratory play session when the children were 3.5 years old. Results indicate that higher levels of risk at birth were associated with less sensitive parenting only among mothers carrying the 7-repeat allele, but not among mothers carrying shorter alleles. Moreover, mothers who are carriers of the 7-repeat allele and whose children scored low on the risk index were observed to have the highest levels of sensitivity. These findings provide evidence for the interactive effects of genes and environment  on parenting, and are consistent with a genetic differential susceptibility model of parenting by demonstrating that some parents are inherently more susceptible to environmental influences, both good and bad, than are others. A great deal of research has substantiated the critical role of parenting in children's development and functioning early on as well as later in life. Parental quality of care  is predictive of a variety of child outcomes, such as attachment security Risk was defined in terms of child medical risk at birth, indexed by children's gestational age at birth, birth weight, and a length of stay at the neonatal intensive care unit (NICU). The (parent) gene that we focused on is the dopamine D4 receptor (DRD4). Several studies have shown that the presence of the exon III 7-repeat allele on the dopamine gene is related to the differential susceptibility of children to parental influences. More recently it has been shown to moderate environmental and child-related stress on parents' sensitivity to their children Having a preterm or low birth-weight infant represents a major stressor for most parents. There is evidence that mothers of preterm infants have more immediate psychological distress and stress related to parenting than mothers of term infants Continued high maternal anxiety can be thought, and was indeed found, to adversely affect mothers' ability to interact sensitively with their infants All that said, empirical findings of the association between preterm birth/birth weight and parenting stress/mother-child interactive behavior are mixed Although parenting has been widely researched with regards to the experiences and attributes that affect parenting, few studies of genetic influences on parenting have been conducted in humans Diathesis-Stress modelOriginally such individuals believed to carry a certain risk—whether genetic, behavioral . Visits were scheduled at a time when children were likely to be at their best and typically completed in less than 2 hours. During the session, the twins were observed individually in a series of tasks. Mothers were then observed interacting separately with each twin, and provided DNA samples.Participants were mothers and their twins taking part in a longitudinal study of twins N = 104 mothers, 199 twins) consisted of families for which (a) mother-child interactions were available with at least one twin , and (b) mother's DNA was available . There were no significant differences between the current sample and the mothers for whom DNA or behavioral assessment were unavailable on any of the study variables , maternal education, socioeconomic status, and child age, though mothers in the former were somewhat younger  than the latter  = 1.93, p<.06, d = .29). On average mothers had completed 15.54 years (SD = 2.57) of formal education. Twins' zygosity was determined by DNA samples. The children consisted of 34 monozygotic (MZ) twin pairs , and 70 dizygotic (DZ) twin pairs .The current sample , defined as follows:Delivery at gestational age of 24 to 32 weeks was considered high risk , delivery at 33 to 36 weeks was rated as moderate risk th percentile relative to Israeli population norms for twins High birth weight risk  was assigned based on the child's low birth weight relative to twins of the same gestational age at the time of birth, defined as falling below the 10Admission to the NICU was considered a risk index based on the following criteria r = .77, p<.001 for MZ pairs, r = .73, p<.001 for DZ pairs) and admission to the NICU  birth risk scores were averaged across twins within pairs.A principal component analysis indicated that week, weight, and NICU risks loaded on one factor accounting for 55.2% of the variance (loadings ranging from .40 to .89). Therefore, total risk at birth was the factor score based on the three (standardized) risk scores. In addition, since the focus of this paper is on mothers as the unit of analysis, and given high inter-pair twin correlations on birth weight (t(99) = 2.44, p<.05, d = .49).Mothers were asked whether one of the twins or both were ever hospitalized (yes/no), and when (open-ended). Answers were screened to exclude NICU hospitalizations, and were coded as 1 if one or both of the twins within a pair were hospitalized and 0 if neither of them were ever hospitalized. Children's hospitalizations were associated with risk at birth scores, Mothers were observed during 10 minutes of free-play with each of their twins. The mother entered each room to play with one of her twins while the other twin was kept busy by the examiner in a separate room. The same procedure was later repeated with the other twin (there were no systematic effects regarding which twin the mother played with first). A colorful set of play-dough and modeling tools was provided and the mothers were asked to play with their child as they would normally do. Mothers' interactions with the children were digitally recorded and later scored by trained research assistants. Observers rated maternal behaviors for each 2-minute segment, and then scores were averaged across the 10-minute session. Different observers independently rated mothers' behaviors towards the two children within each twin pair.Maternal Sensitivity was conceptualized as a multidimensional construct that included maternal warmth, autonomy support, and responsiveness. Mother's Warmth was rated according to the mother's expressed positive affect towards the child, physically and verbally . Ratings ranged from 0 (no expressions of positive affect) to 4 . Autonomy Support was defined as parenting behavior that enhances a child's sense of value and personal control, shows respect for child's ideas, supplies feedback, offers choice, and acknowledges child's cues Positive Responsiveness reflects the frequency in which the mother responded to the child's needs  in a prompt, contingent, supportive, genuinely interested, empathic manner  to 4 .r = .47, p<.001; negativity: r = .26, p<.01), ratings were averaged within pairs. The intraclass consistency coefficient of maternal behaviors between the coders across the five 2-minute segments based on 63 reliability cases were .83 for sensitivity and .87 for negativity.As the focus was on the mothers' responses toward both their twins, and the between-twin correlations for maternal sensitivity and negativity indicated similarity in maternal behavior across twins , 2 µl primers (0.5 µM), 0.6 µl Mg/Cl2 (2.5 mM), 0.4 µl DMSO 5% and 1 µl of water to total of 9 µl total volume and an additional 1 µl of genomic DNA was added to the mixture. All PCR reactions were employed on a Biometra T1 Thermocycler . PCR reaction conditions were as follows: preheating step at 94.0°C for 5 min, 34 cycles of denaturation at 94.0°C for 30 s, reannealing at 55°C for 30 s and extension at 72°C for 90 s. The reaction proceeded to a hold at 72°C for 5 min. The mixture was then electrophoresed on a 3% agarose gel (AMRESCO) with ethidium bromide to screen for genotypes.DNA was extracted from 20 ml of mouthwash samples using the Master Pure kit  with the following primers: χ2(1) = .16, ns, reflecting a random combination and stable frequency of the DRD4 repeat alleles in the population.Twenty eight percent of the mothers were carriers of the 7-repeat allele (three homozygous carriers), and 72% were not carriers , a distribution similar to that found in a comparable sample of mothers . Genotypes were in Hardy-Weinberg equilibrium, p<.10). Further analyses showed identical results when children's hospitalizations were controlled .t = −.94, ns) or presence of the DRD4-7R allele . However, the interaction between risk and DRD4 significantly predicted maternal sensitivity , accounting for 5% of the variance, thus indicating that the relation between risk at birth and later maternal sensitivity depended on the variation in the DRD4 gene. The results remained unchanged with children's hospitalizations statistically controlled in the regression model.As a formal test of the hypothesis that the variation in the DRD4 gene moderates the association between risk at birth and maternal behavior, we regressed mothers' observed sensitivity on risk at birth and their DRD4-III polymorphism , as well as the centered interaction term. There were no main effects of either risk at birth  and DRD4 , however the effect of the interaction term in predicting negativity did not reach significance either . This lack of a significant GXE effect may be due to insufficient variation in negativity as observed in the context of the free-play task, which is not especially designed to evoke it. To test this possibility, we compared the variance of observed negativity to that of maternal warmth and autonomy support . Mauchly's sphericity test  indicated that the variance of the maternal negativity scale was indeed significantly lower than that of the other scales, χ2 = 60.09, p<.001.A similar regression model was used to predict maternal negativity. Again, there were no main effects for risk , which would be consistent with a diathesis-stress model, or whether it relates to a susceptibility to both negative as well as positive contexts, which would be consistent with a differential susceptibility model. To test this we needed to depict a full range of this environmental variation. Although twins' gestation is considered a higher risk pregnancy and birth in general in the obstetrics literature, for descriptive purposes we divided risk at birth into three subcategories consisting of low risk , medium risk (29%), and high risk . N = 199) when their scores  are treated separately. Because twin pairs come from the same family their scores cannot be assumed to be independent. To account for this nonindependence among twins, generalized estimating equations with robust covariance estimators were used with twin pairs clustered by family. Results were similar to those reported above. No significant relationship was found between risk at birth and maternal sensitivity for the full sample (B = −.08), Wald χ2 (1) = 1.46, ns, as well as among the DRD4-7R non-carrier mothers only (B = −.004), Wald χ2 (1) = .003, ns. In contrast, among the mothers carrying the 7R allele, risk at birth was negatively associated with maternal sensitivity (B = −.31), Wald χ2 (1) = 6.27, p = .01.In addition to examining the associations between scores averaged across twins, in follow up analyses we also tested whether the effects replicate for the individual twins . Family influences are not unilateral and children affect the parenting they receive. Thus, further research might point to ways in which children's DRD4 genotype interplays with maternal DRD4 and environmental factors to predict parental behavior.As a direction for future study to further dissect the influences of the factors involved in shaping maternal behavior, it would be of interest, in addition to focusing on maternal genotype, to assess the contribution of The study has several strengths. Foremost, it is among the first studies to implement the field of molecular genetics in studying parenting behavior by taking into consideration the effects of parental genes, in combination with child-based environmental influences, to study the quality of parent-child interactions. Second, differential susceptibility theorists as well as molecular genetic scholars call for inclusion of observed behavioral assessments  to a low stress condition (delivering a baby at no immediate risk). This variation did prove diverse enough to identify mothers who appear more susceptible to both the high and low ends, and were observed to have both lower and higher levels of sensitivity, respectively. However, to truly demonstrate susceptibility to enriched, highly positive environments, it is recommended to not merely consider the presence versus absence of adversity but also focus on intrinsically positive life experiences or favorable environments Third, the birth-risk index used in the study is limited in that it does not directly assess specific medical risks and complications  that are not necessarily associated with preterm, low birth weight, and NICU hospitalization. Additionally, we did not address the mediating mechanism between child risk at birth and maternal sensitivity three and a half years later that can explain what mothers are responding to in their high versus low-birth-risk children resulting in different levels of sensitivity. As detailed in the Forth, maternal behavior was assessed during a single observation of mother-child interaction. As responses to one's child vary across contexts, a more extensive assessment of parenting employing repeated observations would increase the confidence that the observed behaviors reflect mothers' interactive patterns. For example, it appears that the observational context employed in this study  did not evoke much variation in maternal negativity. That said, confined to a single observation we chose a relatively unstructured task  as to minimize constraints on maternal behavior, and thus to allow for individual differences in sensitivity to emerge.Finally, our sample consisted of mothers of twins. On one hand, it likely assisted in having enough variance on the risk measure, as twins are more likely to be preterm and of low birth weight. On the other hand, the unique challenges in parenting twins may limit the generalizability of our findings. Twins' mothers may be at greater risk for increased anxiety Sensitive and responsive parenting has been shown to be critical for children's cognitive and socioemotional development e.g., . It is t


Acute lower respiratory infections (ALRIs) are leading causes of hospitalisation in children. Birth defects occur in 5% of live births in Western Australia (WA). The association between birth defects and ALRI hospitalisation is unknown.We conducted a retrospective cohort study of 245,249 singleton births in WA (1996-2005). Population-based hospitalisation data were linked to the WA Register of Developmental Anomalies to investigate ALRI hospitalisations in children with and without birth defects. We used negative binomial regression to estimate associations between birth defects and number of ALRI hospitalisations before age 2 years, adjusting for known risk factors.Overall, 9% of non-Aboriginal children and 37% of Aboriginal children with birth defects had at least one ALRI admission before age 2 years. Aboriginal children  and non-Aboriginal children  with birth defects had higher rates of hospitalisation for an ALRI than children with no birth defects. Rates of ALRI hospitalisation varied by type of defect but were increased for all major birth defects categories, the highest rate being for children with Down syndrome . The rate of ALRI hospitalisation was 3 times greater in children with multiple birth defects than in those with isolated defects.Children with birth defects experience higher rates of hospitalisation for ALRIs before age 2 years than children with no birth defects. Optimal vaccination coverage and immunoprophylaxis for specific categories of birth defects would assist in reducing hospitalisation rates for ALRI. Acute lower respiratory infections (ALRIs) are a major cause of hospitalisation in young children . ChildreALRI hospitalisation rates are high among Indigenous populations living in industrialised countries, including Aboriginal Australians . RecentlWe have previously used population-based linked data from the Western Australian Data Linkage System (WADLS) to investigate the burden and causal pathways to ALRI hospitalisation in young children -11. The 2 and in 2005 had a population of 2 million, 3% identifying as Aboriginal or Torres Strait Islander [WA covers an area of 2.5 million kmIslander .The WADLS has been operating since 1995. It constitutes a powerful source for population-based research on health outcomes, while overcoming limiting issues relating to sample size and accurate exposure and outcome ascertainment ,21. LinkICD10 codes were introduced in July 1999. Similar to our previously published work , ICD9 coThe WARDA has population-based information on birth defects for all children born in WA since 1980 . WARDA rst December 2005) or death.We used negative binomial regression to calculate incidence rate ratios (IRR) with 95% confidence intervals (CI) to estimate the association between categories of birth defects  and the number of ALRI hospitalisations during the first two years of life, adjusting for sociodemographic characteristics that we previously identified as risk factors for ALRI and were also potential confounders. These were gender, gestational age , percent optimal birthweight  , the Western Australian Aboriginal Health and Information Ethics Committee (WAAHIEC), and the Princess Margaret Hospital for Children Ethics Committee. Access to linked data was provided by the WA Department of Health. All data files had identifying data removed before being provided to the research team.Between 1996 and 2005 there were 13,316 (n = 5.4%) live-born singleton children with birth defects from the population of 245,249 singleton live births . Overall, 11,977 (90%) had isolated birth defects, 1,331 (10%) had multiple birth defects and 8 cases were missing information on their birth defects category. In addition to Down syndrome, the birth defects most commonly found as one of multiple defects were musculo-skeletal defects, cardiovascular defects and CA of ear, face and neck.Table Both Aboriginal and non-Aboriginal children with birth defects had twice the rate of hospitalisation for an ALRI before age 2 years compared with Aboriginal and non-Aboriginal children with no birth defects, after adjusting for all known risk factors (Aboriginal IRR = 2.3; 95% CI 1.9, 2.8; non-Aboriginal IRR = 2.0, 95% CI 1.8, 2.2; Table To investigate any differences between types of ALRI, we investigated the association between birth defects and bronchiolitis and pneumonia. As the vast majority of bronchiolitis hospitalisations occur in the first year of life, the outcome for bronchiolitis was restricted to that age group. The rates of admission for any ALRI before age 2 years, bronchiolitis in the first year of life, or pneumonia before age 2 years were higher in Aboriginal and non-Aboriginal children with multiple birth defects than in those with isolated birth defects Table . In partDue to small numbers of individual birth defects in the major categories and subcategories, we combined data from Aboriginal and non-Aboriginal children to investigate the association between different types of birth defects and ALRI hospitalisations. After adjusting for all known risk factors, there was a positive association between all major categories of birth defects and hospitalisation for any ALRI in the first 2 years of life, bronchiolitis in the first year of life and pneumonia in the first 2 years of life Table . There wUsing total population-based data, we have shown that children in WA with any birth defect have a two-fold higher rate of hospitalisation for ALRI in the first 2 years of life than children with no birth defects. In addition, the rates of hospitalisation for ALRI were higher in children with multiple birth defects than children with isolated birth defects. The rates were increased in all major birth defect categories and for both bronchiolitis in the first year of life and pneumonia before the age of two years. Our findings are consistent with previously reported studies that have generally investigated a pathogen-specific ALRI such as that caused by RSV or have only considered a specific birth defect or syndrome such as Down syndrome ,7. To ouHaemophilus influenzae type b, pertussis, measles and influenza vaccines for prevention of ALRIs.There are a number of reasons why children with birth defects are at increased rate of hospitalisation for ALRI which will vary according to the type of birth defect. There may be anatomical defects that increase risk of pathogens entering the upper respiratory tract and lung, they may be born preterm, of low birthweight and children may have a compromised immune system making them more susceptible to infection. Children with Down syndrome may have abnormal airway anatomy, congenital heart disease and hypotonia impairing swallowing and putting them at risk of aspiration. Surgery under anaesthetic increases risk of ALRI and many children with birth defects require surgical management. For all these reasons, unless specifically contraindicated, it is important that children with birth defects receive vaccines according to standard schedules, specifically pneumococcal, There are several limitations to our study. Firstly, our linked hospitalisation data only included hospitalisations with a respiratory infection diagnosis and not all admissions for children with birth defects. Therefore, we do not know whether the birth defects were surgically corrected and, if so, whether this occurred prior to any hospitalisations with a diagnosis of ALRI. Secondly, we do not have information on other potential risk factors such as breast feeding and duration of breast feeding, the child’s immunisation status and child care attendance. Lastly, we were unable to determine if and where individuals moved within or outside the state during the study period. Therefore information related to socioeconomic status and the accessibility/remoteness index may have changed between the time of birth and time of hospitalisation. However we believe this is likely to have had little impact on our results  as, geneImmunoprophylaxis with the RSV monoclonal antibody, palivizumab, is effective in reducing severe RSV-related hospitalisations, mostly associated with bronchiolitis and pneumonia . PalivizIn summary this total population-based study has provided useful information on the rate of hospitalisation for ALRI for a broad range of birth defects in Aboriginal and non-Aboriginal Australian children. Primary prevention of and prenatal screening for birth defects, optimal vaccination coverage and immunoprophylaxis for specific categories of birth defects will assist in reducing hospitalisation rates for ALRI.The authors declare that they have no competing interests.All authors developed the study design. KhJA cleaned and analysed the birth defect data and drafted the manuscript. HM cleaned the original datasets from the previous analysis, conducted part of the current data analysis and assisted in the preparation of the manuscript. PJ provided expert statistical advice. CB provided expert clinical advice on the birth defects data and interpretation of results. DL provided expert advice on all issues and provided support throughout the study and critically reviewed the draft manuscript. All authors read and approved the final manuscript prior to submission.The pre-publication history for this paper can be accessed here:http://www.biomedcentral.com/1471-2431/14/80/prepub


Although life course influences have long been recognised in affective disorder, little is known about the influence of early life factors on late life anxiety and depression. The aim was to investigate the extent to which birth measures, maternal health and family circumstances were associated with symptoms of anxiety and depression in late life.A retrospective cohort study was constructed from a cross-sectional survey sample of community residents aged 72–74 years, 406 of whom had traceable birth records. Cases and controls for late life anxiety and depression were defined applying standard cut-offs to the Hospital Anxiety and Depression Scale. A range of measures and circumstances were extracted from birth records blind to survey data and compared in age- and gender-adjusted models.There were no differences in any anthropometric measure in either case control comparison. Case-level anxiety and depression were both associated with significantly lower maternal age. Late-life anxiety was additionally associated with smaller maternal pelvic size and the mother’s condition being rated as poor at birth/discharge. Late-life depression was associated with a lower status paternal occupation.There was no evidence for a substantial influence of early life size on late life affective disorder. However, there was some evidence in secondary analyses for an enduring influence of the family’s socioeconomic environment and maternal health. Anxiety and depression are highly prevalent disorders among older adults ,2 and, wThe developmental origins of adult health and disease (DOHAD), originally known as “the Barker hypothesis”, is commonly applied as the framework for understanding empirically observed links between processes at prenatal stages and adult chronic disease ,6. The DThe DOHAD-hypothesis has also been applied to investigate the aetiology of mental disorders, proposing that prenatal factors can modify risk . Low birTo our knowledge, only three studies have investigated the impact of early life factors and late-life mental health. Thompson and colleagues found that foetal undernutrition predisposed men, but not women, to depression at age 68 . A recenIn summary, there is some evidence suggesting an association between foetal and early origins of anxiety and depression in adulthood. This is however not consistently supported in the literature, with study design differences and elements of publication bias suggested as possible reasons for heterogeneity. Compared to research on depression in old age, anxiety disorders have received very little attention , despiteTaking advantage of a birth record archive in an area covered by a cross-sectional survey of older people’s mental health in Bergen (Norway), we constructed retrospective cohort study to investigate the relationship between the early life environment and late life anxiety and depression. This allowed for a follow-up from the 1920s to the 1990s. Primary hypotheses were that smaller anthropometric measures would be associated with case status for both syndromes. Secondary analyses investigated other information reflecting parental health and early life socioeconomic status.During the late 19th century and early 20th century, Bergen city expanded geographically and qualitatively from a semi-rural city to one with more modern characteristics. Primary industry which had dominated, gave ground to expanding secondary and tertiary industry . This chThe sampling frame for this study comprised all 3,341 (77% of the invited) participants of the old age cohort of the population-based Hordaland Health Study (HUSK) which has been previously described [In this study, we sought to link as many members as possible of the HUSK sample to their birth records in order to construct a nested retrospective cohort study within the linked subgroup, comparing historically recorded information at birth between participants with/without a mental disorder in late life. In the Norwegian Population Registry, all inhabitants of Norway are registered with a personal identification number. Using this individual identifier, the names , date of birth, place of birth and parents’ names (if available) of HUSK participants were retrieved. This information was used to trace the participants born in Bergen to the public maternity ward (“Fødestiftelsen i Bergen”) birth records located at the Regional State Archives of Bergen. In the second decade of the 20th century, about one quarter of all births in the Bergen area took place in the official maternity ward . The portion of deliveries taking place at hospitals increased steeply when the new Women’s Clinic (“Kvinneklinikken”) was inaugurated in 1926, replacing the old maternity ward. The relevant birth records for the present study were those detailing births between 1st of January 1925 and 31st of December 1927. These records contain detailed information about the pregnancy, the birth and the mother’s health recorded by midwives and obstetricians during the hospital stay. The Women’s Clinic in question was the main teaching facility for midwifes at the time, and the records were integral to the training, and are therefore considered to be of high quality .The available birth records in the Regional State Archives of Bergen were viewed and coded by researchers blind to all measurements made in HUSK. The following information was abstracted from each record : birth weight (kg), birth length (cm), head circumference (cm) at birth, ponderal index , mother’s pelvic size (cm), mother’s age (years), and gestation (weeks). The following binary variables were derived from individual free text fields: any recorded disease in the mother, family history of coronary heart disease (yes/no) and tuberculosis (yes/no), the state of mother’s teeth (poor/good), complications during birth (yes/no), mother’s condition after birth ), mother’s condition at discharge , and indicators of socioeconomic status included marital status (married/unmarried), father’s occupation , and type of payment for the hospital stay .Cases and controls were defined according to the presence of anxiety and depressive symptoms in late life, ascertained in HUSK participants using the Hospital Anxiety and Depression Scale (HADS) . HADS asTo assess potential demographic differences between the participants we were able to trace and the remaining HUSK participants, we obtained gender, self-reported level of educational attainment and general health from HUSK. Level of educational attainment was divided into “compulsory only” and “post-compulsory”, while general health was divided into “poor” and “good”.Of the 3,341 HUSK-participants  was emplpost hoc power analysis indicated that we would be able to detect a small to medium effect size for mean group differences (Cohen’s d of 0.39) and binary associations (Cohen’s w of 0.18), given a power of 80% for the main HADS-A and HADS-D analyses [Using the software G*Power version 3.1.3 , a post analyses -51.The data in HUSK was collected in accordance with ethical standards required by the regional ethical board of Committees for Medical and Health Research Ethics in Norway (REC). The permission to collect and store the data from HUSK was given by the Norwegian Data Inspectorate. All participation in HUSK was voluntary, and all potential participants received written information about the project before they met for examination. The participants gave their written statements of informed consent, including the specific consents to use information from HUSK in health research and to link this information with other relevant data sources. The participants also gave their written statement that they were informed that no specific time-limit was set for the storage of data. This specific study was reviewed and approved by REC. The current study adheres to the standards of the declaration of Helsinki.No differences between the HUSK-participants with birth journal information and participants without were found regarding gender p=0.814), self-reported health (p=0.706), case-level anxiety (p=0.531) or case-level depression (p=0.621). However, participants we were able to trace had a significantly higher educational attainment (p=0.025) than the untraced. The proportion of participants with case-level anxiety and case-level depression in the traced sample was 14.3% and 9.4%, respectively. No differences were found on exposures obtained at birth between those with valid HADS subscales (n=406) and those without (n=74), all p-values ranging between 0.087-0.990. Out of the 406 HUSK-participants included in the present study, 54.2% (CI95% 49.3-59.0) were female, and the mean age was 72.3 (SD: 0.9) years. The sample-characteristics obtained at birth are summarized in Table 4, self-rIn the main analyses, none of the anthropometric measures at birth, such as weight and length, differed significantly between cases and controls in either comparison Table , and outMany previous studies have found an association between early life factors and later mental health problems, but most of these have been limited to follow-up into childhood, early adulthood or middle-age. In this study investigating risk factors present at birth in relation to anxiety and depression in old age, no associations were found for the anthropometric measures of principal interest. However, there was evidence in secondary analyses for associations with factors that might indicate worse maternal health and/or socioeconomic status.This study had several strengths. Having access to birth records from the 1920s and the possibility to link this information to a population-based health survey in the late 1990s enabled examination of an interval between exposure/outcome status in the range of 72–74 years. The exposure source contained detailed, accurate and rich anthropometric measurements , as well as information about maternal health and circumstances, the birth process and the early post-natal period. This information is unlikely to be biased in any particular direction. The birth records were carried out as a key element in the education of midwives under the supervision of the head physician. The HUSK study included a validated and often used screening inventory for symptoms of anxiety and depression. Furthermore, both men and women were represented in our sample, enabling identification of any confounding by gender.Limitations include the relatively small sample size and proportion of the HUSK-participants that could be traced back to their birth records. There are several reasons for this: the birth records were only available for a subgroup as not everyone who participated in HUSK was born in the Bergen area, and some born at home or at other hospitals. Based on a conservative estimate, at least one-third of the HUSK sample would not be within the catchment area of the regional hospital at the time of birth. The small sample size reduces our ability to detect potential small but meaningful effects. A recent meta-analysis investigating the association between low birth weight and depression later on found only small effects  – and giThe outcome measure, HADS, is a screening instrument for anxiety and depression, primarily designed to measure these syndromes in a general hospital population. In the age group in this study, a measurement which specifically focuses on cognitive rather than somatic symptoms of anxiety and depression may have benefits in avoiding over-ascertainment due to physical health problems, which are relatively common in this age group. The HADS has been found to have good case-finding properties in a GP setting  althoughOut of the three previously published papers on the relationship between factors present at birth and anxiety and depression in old age ,14,25, oOur results are, however, not in line with the finding from the Swedish study where both low birth weight and shorter gestational age at birth were independent risk factors for life-time depression among women , althougAs the life expectancy in many societies has increased, many individuals will live longer, and the pool of older adults with mental disorders will increase. Despite this development, less attention has been directed towards identifying risk factors for late life mental disorders, especially anxiety, than in younger age groups ,62. A beThe authors declare that they have no competing interests.JCS, AM and RS were responsible for the conception this study, and the study design was developed by JCS, AM and RS. Analyses were carried out by JCS under supervision of RS and SØ, and manuscript preparation was led by JCS in cooperation with RS, SØ and MK. JCS, SØ, MK, AM and RS were all involved in the interpretation of data, drafting the article and approval of the final manuscript. JCS is the guarantor for the study.The pre-publication history for this paper can be accessed here:http://www.biomedcentral.com/1471-244X/13/136/prepub


A 17-year-old woman had undergone exploratory laparotomy because of a huge cystic pelviabdominal mass equivalent of 36 weeks' gestation. A closed system drainage maneuver was applied via using a laparoscopic trocar to drain a revealed large left paraovarian cyst. This maneuver was found to be a simple and effective method to safely aspirate giant paraovarian cysts; thus allowing their total excision. Paraovarian cysts constitute 10–20% of all adnexal masses2. Some paraovarian cysts may reach a large size with possible complications like torsion and rupture3. These cysts are usually benign and rarely malignant5. In this report, we present how we surgically managed a case with an abnormally huge paraovarian cyst.Paraovarian cysts occur in the broad ligament between the ovary and the tube, predominantly arising from mesothelium covering the peritoneum  but also occasionally arise from the paramesonephric tissue (paramesonephric cysts or Mullerian cysts) and rarely from mesonephric remnants (mesonephric cysts or Wolffian cysts)A 17 years old virgin presented with diffuse abdominal pain. History revealed a gradual increase of an abdominal swelling over the preceding 6 months. Physical examination showed a non tender, tense cystic pelvi-abdominal mass of 36 weeks gestational size. Computerised tomography revealed a 25 × 26 cm left ovarian simple cyst with clear contents and no septae. Serum CA125 level was normal. Other tumor markers were not performed due to financial constraint. Through a subumbilical midline incision, a huge smooth cystic mass overlying the whole abdominal cavity was found. The cyst was isolated from its surroundings with gauze packs. A loose purse string suture was placed in the lowest accessible part of the cyst. A 5 mm laparoscopic trocar with a side track off its main sleeve was connected to a high pressure suction irrigation device via a rubber tube. The trocar was then inserted through the center of the suture which was subsequently stretched to fit around the sleeve. This created a closed system to drain the cyst. The trocar was removed leaving its sleeve in place and suction drained eight liters of clear watery fluid. The collapsed cyst was found to be left paraovarian, which was exteriorized and the trocar sleeve was removed. The purse string suture was tightened to close the trocar opening. The left broad ligament was opened and the cyst wall was completely removed from the broad ligament . The redPostoperative histology reported simple benign serous cyst of mesothelial origin. The peritoneal fluid showed proteinaceous material entangling few lymphocytes and mesothelial cells with no evidence of malignancy.8. Only one report for three adolescents with large paraovarian cysts (with a range of 20–26 cm) had addressed decompression techniques before cyst exteriorization and excision using a suction cannula9.Huge paraovarian cysts are uncommonly reported in the literature. We reviewed the English literature and were able to find three reports about the management of comparably huge cysts. In these reports, surgeons utilized abdominal incisions extending over the umbilicus, much larger than the one we used, in order to allow for cyst extraction and excision11. Darwish et al. reported a series of smaller paraovarian cysts which had been excised laproscopically; the largest was not more than 13 cm12. They reported either cyst aspiration and forceps coagulation of small cysts or cyst wall trocar puncture followed by suction and extraction for large cysts. Laparoscopy would have been technically difficult in our case due to the huge size of the cyst reaching close to xiphesternum. Direct abdominal entry with a Veress needle or trocar might have traumatized the cyst leading to spillage of its content. It is the authors’ view that laparoscopic cyst decompression before its removal is associated with greater risk of cyst spillage than the technique we describe. We therefore, through laparotomy and a small surgical incision, employed a closed drainage system to safely aspirate the cyst followed by excision.Two reports dealt with large paraovarian cysts laparoscopically. The first was a simple paraovarian cyst associated with pregnancy which measured 20 cm while the second with acute lower abdominal pain measured 12 cmOpen surgery remains the gold standard route to deal with giant paraovarian cysts. Aspiration of the cyst using a closed system followed by excision is a safe and effective treatment.Written informed consent for publication of the clinical details and clinical images was obtained from the patient. I have read this submission. I believe that I have an appropriate level of expertise to confirm that it is of an acceptable scientific standard. This case is interesting and shows the ability to manage big ovarian cysts laparoscopically. Important issues during the procedure, like the closure of the cyst incision site with sutures to prevent spillage, were correctly addressed.I have read this submission. I believe that I have an appropriate level of expertise to confirm that it is of an acceptable scientific standard. An interesting case report that may help others when they come to deal with similar cases. A little more detail in the other methods alluded to in the laparoscopic cases might be helpful. The grammar and language needs editing.I have read this submission. I believe that I have an appropriate level of expertise to confirm that it is of an acceptable scientific standard.


A number of studies have reported on the effects of iron supplementation in low birth weight infants; however, no systematic review of the available evidence has been conducted to date. Hence, we performed a systematic review of the literature to examine the effects of iron supplementation on hematologic iron status, growth, neurodevelopment, and adverse effects in low birth weight/premature infants.We searched the Cochrane Library, Medline, and PubMed for articles reporting on the effects of iron supplementation in low weight infants. The following search terms were used: “preterm born infant(s)/children”; “preterm infants”; “prematurely born children” “weight less than 1500 g at birth”; “born prematurely”; “low birth weight infant(s)”; “infants born preterm”; “prematurity”; “small-for-gestational age”; “very small gestational age infants”; “iron supplementation”; “iron intake”; “iron supplements”; “ferric and/or ferrous compounds”; and “ferrous sulphate/fumarate/sulfate”.A total of 15 studies were identified and included in the systematic review. Supplemental iron was given orally or as an iron-fortified formula in 14/15 studies. The duration of treatment ranged from 1 week to 18 months. Iron supplementation significantly increased hematologic measures of iron status  relative to placebo or over time in most studies. All controlled studies that examined iron-deficiency anemia (IDA)/ID reported a decreased prevalence of IDA/ID with iron supplementation. Dose dependent decreases in the prevalence of IDA/ID were reported in several studies. Of the 5 studies reporting on growth, none found any significant effect on growth-related parameters . Only 2 studies reported on neurodevelopment; no marked effects were reported. There were no consistently reported adverse effects, including oxidative stress, inhibited nutrient absorption, morbidity, or the requirement for blood transfusion.The available data suggest that iron supplementation increases the levels of hematologic indicators of iron status and reduces the prevalence of IDA/ID in low birth weight/premature infants. There is insufficient evidence to make a definitive statement regarding the effects of iron supplementation on growth, neurodevelopment, or the occurrence of adverse effects in low birth weight/premature infants. Iron is an essential micronutrient that plays a critical role in many cellular functions and processes, including growth and development. As such, having an adequate supply of iron, along with other micronutrients, is thought to be particularly important for infants . Low birThe potential consequences of IDA during infancy include impaired development -11 and aThe Cochrane Library, Medline, and PubMed databases were searched from inception to June 2011. We limited the searches to include only articles written in English using the following terms: “preterm born infant(s) / children”; “preterm infants”; “prematurely born children” “weight less than 1500 g at birth”; “born prematurely”; “low birth weight infant(s)”; “infants born preterm”; “prematurity”; “small-for-gestational age”; “very small gestational age infants”; “iron supplementation”; “iron intake”; “iron supplements”; “ferric and/or ferrous compounds”; and “ferrous sulphate / fumarate / sulfate”. Boolean operators  were also used in succession to narrow and widen the search. To locate unpublished materials and avoid systemic bias, we manually searched the references lists of original and review articles for symposia proceedings, poster presentations, and abstract from major pediatric association meetings.Studies were eligible for inclusion if they involved infants who were of low birth weight (< 2500 g) or premature  and received iron supplementation through the enteral (formula or iron drops) or parenteral routes. Studies involving supplementation of other micronutrients were also eligible for inclusion if the only difference between the treatment and the control groups was iron supplementation.Studies were excluded if there was no definite length of treatment available, or if supplementation was combined erythropoietin treatment.The search and inclusion and exclusion criteria were developed by an investigative team, including experts in the field of pediatric development and nutrient research. Our team included a biostatistician who was instrumental in defining the criteria.The first step in study selection was the exclusion of duplicates . The title and abstract of the trials retrieved in the search were scanned and studies that were obviously irrelevant were excluded. The full text of each remaining study was reviewed to establish eligibility and all relevant information and data were extracted.Data were extracted by 3 independent reviewers. Each reviewer used a standardized data collection form to increase uniformity and reduce bias. In the case of discrepancy, the reviewers made a consensus decision. The following information / data were extracted from each eligible study: first author; year of publication; journal; eligibility criteria; definition of premature or low-birth weight; number of cases and control; population demographics; hematological data  before iron supplementation; iron supplement dose; duration of iron supplementation; hematological data after iron supplementation; growth status after iron supplementation; and adverse effects of iron supplementation.The quality of each study identified for inclusion was assessed using the Delphi list for quality assessment of randomized clinical trials .A total of 2065 articles were identified by searching the 3 databases and a further 3 articles were identified by bibliographic searches Figure . Of thesThe studies included in this systematic review were published between 1960 and 2010 and included low birth weight infants aged from birth to 80 days , had similar between group characteristics at baseline , specified eligibility criteria , provided point estimates and measures of variability for the primary outcome measures , and included an intention-to-treat analysis . Only 6/15 (40%) studies provided any definitive information about blinding   among the 3 studies in which mean values were available and dose was adjusted for body weight ,34,35.All but 1 study reported on the effects of iron supplementation on hematologic measures of iron status Table . The majIn a non-placebo controlled study, Arnon et al. found that premature infants fed enteral iron (5 mg/kg/day) from 2 weeks of age to 8 weeks of age had significantly higher hemoglobin, reticulocyte, iron, and ferritin concentrations compared with premature infants fed enteral iron (5 mg/kg/day) from 4 weeks of age to 8 weeks of age . In anotA small number of studies included in the systematic review found that iron supplementation had no significant effect on hematologic measures of iron status relative to control. These include studies by: Friel et al., in which low birth weight infants were fed either a normal (0.6-3.0 mg/kg/day) or high (0.6-5.9 mg/kg/day) iron formula from birth for 12 months ; Miller A study by Griffin et al. compared the effects of formulations containing either 0.9 mg/dL iron or 0.5 mg/dL iron in premature infants and found that there were no dose-dependent differences in hematological indicators of iron status . In anotMost studies reported on the prevalence of iron deficiency (ID) and/or IDA Table . All conOnly 1 study found no obvious benefit of iron supplementation on the prevalence of ID and/or IDA. Brozovic et al. reported that oral iron (36.3 mg/day) from 5 weeks to 9 months of age did not prevent ID in premature low birth weight infants .Five studies included in the systematic review examined the effect of iron supplementation on growth, whereas only 2 studies examined the effect of iron supplementation on neurodevelopment Table . None ofSeveral studies included in the systematic review examined potential adverse effects of iron supplementation, including oxidative stress, inhibition of nutrient absorption, neonatal morbidity, the requirement for blood transfusion, and other adverse effects Table . None ofThis is the first systematic review to focus on the effects of iron supplementation in low birth weight / premature infants. Only a relatively small number (N = 15) of studies were identified for review. Several consistent findings were apparent with iron supplementation, including increased concentrations of hematologic indicators of iron status, decreased prevalence of ID / IDA, and a lack of an effect on growth parameters. Few studies that met the criteria for inclusion in our review reported on the effects of iron supplementation on neurodevelopment or the occurrence of adverse effects.Our observation that iron supplementation generally increased concentrations of hematologic indicators of iron status  in low birth weight / premature infants is consistent with the findings of other systematic reviews / meta-analyses which examined the effects of iron supplementation on hematologic indicators of iron status in children  and younAs low birth weight / premature infants are particularly vulnerable, and given the fact that humans have no physiologic mechanism for excreting iron, it is important to consider the possibility of iron overload with iron supplementation and identify any potential adverse effects of iron supplementation. Adverse effects of iron supplementation have been suggested, including oxidative stress  and an iThis systematic review has a number of limitations that must be acknowledged. Perhaps the most important limitation is was the lack homogeneity between studies in terms of treatment dose, length of treatment, timing of treatment, age of the infants, length of follow-up, and variables assessed. These differences clearly make between study comparisons difficult and almost certainly explain some of the variability in findings. Another limitation is that the length of follow-up was relatively short for the assessment of growth and neurodevelopment. It is possible that any beneficial effects of iron supplementation on development may become apparent many years after supplementation has ceased. Indeed, in the only study with follow-up > 18 months, Steinmacher et al. found that more infants who received late vs early iron supplementation had abnormal neurologic examination findings at a median of 5.3 years of age . AlthougIn conclusion, our review leads us to suggest that iron supplementation can improve indicators of hematologic iron status and reduce the occurrence of ID / IDA in low birth weight / premature infants. The benefits of iron supplementation on growth appear to be limited, at least in the short term (within 18 months of treatment), whereas there is insufficient evidence on the effects of iron supplementation on neurodevelopment or the occurrence of adverse events in this population. Quite clearly larger scale, randomized controlled trials are needed to determine whether iron supplementation in low birth weight / premature infants affects neurodevelopment (short and long term) and long term growth, and to comprehensively monitor potential adverse effects. Such studies should also aim to determine if specific cohorts of low birth weight / premature infants are more likely to benefit from iron supplementation, and the optimal dose, timing, and duration of iron supplementation.We have no competing interests to declare.HL screened studies for inclusion, abstracted data, analyzed data, and drafted the manuscript. JY screened studies for inclusion, abstracted data, analyzed data, and drafted the manuscript. PH screened studies for inclusion, abstracted data, analyzed data, and helped to draft the manuscript. ZL verified outcomes data, assessed study quality, analyzed data, and helped to draft the manuscript. WQ, FW, and SZ critically revised the manuscript for important intellectual content. All authors read and approved the final published manuscript.The pre-publication history for this paper can be accessed here:http://www.biomedcentral.com/1471-2431/12/99/prepub