In China, and in Shandong province, the proportionate contribution of birth defects to infant mortality has increased, and congenital heart disease (CHD) is now the most common cause of birth defects. The cause of approximately 90% of cases of congenital heart disease is multifactorial. Little is known about modifiable environmental risk factors or regional differences. We investigated putative environmental risk factors for congenital heart disease in the Shandong province of China in order to improve prevention of CHD.We conducted a hospital-based 1:2 matched case–control study of 164 patients with congenital heart diseases and 328 controls, all of whom were retrospectively interviewed. Univariate and multivariate analyses were conducted to identify environmental risk factors for CHD.The environmental risk factors associated with CHD were mother’s education level , neonatal asphyxia or hypoxia , number of previous pregnancies , maternal upper respiratory tract infection , maternal infection , maternal B-mode ultrasound examination , and maternal mental stress  during early pregnancy. No significant interactions were observed among these factors.Augmenting maternal mental healthcare, obtaining regular health counseling and testing during pregnancy, preventing upper respiratory tract infections, limiting medication during early pregnancy, offering health promotion and health education to women of childbearing age , and improving obstetric procedures and techniques may lower the occurrence of congenital heart disease. All cases were younger than 7 years and had a diagnosis of, or been treated for, CHD  between January 2004 and January 2005. Diagnoses were confirmed by appointed senior pediatric cardiologists, based on case records.The exclusion criteria for cases included: 1) presence of abnormalities in other organs, 2) death of birth mother, 3) divorce of birth mother, or 4) mental disorder diagnosed in birth mother, 5) inability to locate birth mother for interview, and 6) unwillingness of birth mother to be interviewed.Two hospital-based controls were recruited to match each CHD case. The controls were recruited from inpatients, outpatients, or patients undergoing health checkups at the same medical institutions during the same period. Inpatients were preferred because their diagnoses were clear and easily obtainable. If the number of inpatients was deemed insufficient, outpatients, and then other patients, were enrolled. The matching criteria for controls were: 1) same sex, 2) age difference of less than 1 year, and 3) same geographic classification . A control with a diagnosis of CHD or other birth defect was excluded. Controls were also excluded for the abovementioned criteria 2)–6). When a new case was confirmed, we downloaded all information on eligible patients from the hospital information system, using the matching criteria. The 2 eligible and available controls whose time of presentation at hospital was closest to that of the case were selected.Cases and controls were all born in Shandong province, and their birth mothers were local residents. The birth parents of participants were interviewed for this study.In each medical institution, one senior pediatric cardiologist was appointed to identify CHD cases and patients with other birth defects, and to confirm participant eligibility. One interviewer, who was masked to the participant’s group assignment, conducted face-to-face interviews of the participant’s birth parents using a standardized questionnaire. The pediatric cardiologists and interviewers were trained uniformly before the formal interview and, to further refine the format of the questionnaire and the skills of the investigators, a preliminary trial of the interview and questionnaire was conducted with the participation of a few patients’ parents from other medical institutions. All the participants’ birth parents were retrospectively interviewed in a similar manner during the period of the study. Informed consent was obtained from each participant.The content of the questionnaire included:1)Demographic characteristics: child’s name, sex, birth date, address, and nationality, and parents’ education levels.2)Conditions of participant's birth: gestational age, birth weight, fetal order, birth asphyxia or hypoxia.3)Characteristics of birth parents: age at pregnancy, consanguineous parents, family history of inherited disease, occupational exposure history, disease history, and lifestyle .4)Conditions of pregnancy: gynecologic examination results, gestational weeks until aware of pregnancy, abnormal pregnancy reactions , reproductive history, and environmental exposures .All data entry was completed independently by two external staves, and a database was established using Microsoft Excel 2003 after logical checking.x2, ln(x), ln(1 − x) or x ln(x), were all applied to each discrete ranked variable and each continuous quantitative variable to identify possible nonlinear relationships between x and logit p. Dummy variables were also created for some factors. Grouping analysis was performed on correlative variables that were statistically significant on univariate analysis. Then, based on professional judgment, we determined the candidate variables for multivariate analysis. Next, a multicollinearity diagnosis was conducted for these candidate variables, using principal component analysis. The variables were adjusted if multicollinearity was present. Finally, multivariate conditional logistic stepwise regression analysis of suspected interactive variables was performed to screen for possible risk factors for the occurrence of local CHD, and the adjusted odds ratio (OR) and 95% confidence interval (CI) were obtained. All P values were calculated using a 2-tailed statistical test, and P < 0.10 was considered statistically significant in univariate analysis. All analysis was completed using SAS statistical software, version 9.1. For the 1:2 matching conditional logistic regression analysis, the PHREG procedure was used.Variables with data structure problems were removed by constructing frequency graphs and cross-table analysis. Univariate conditional logistic regression analysis was conducted after some research factors had been quantitatively assigned. Other transformed functions, such as Early pregnancy—The period from 1 month before to 3 months after insemination . The time of exposure was early pregnancy, unless otherwise specified.Grouping analysis—In order to avoid the influence of strongly correlative variables in the establishment of the multivariate regression model, we performed multivariate conditional logistic regression analysis only with 2 or more strongly correlative variables entered simultaneously in a single step. Then, the more significant variable was selected for the subsequent multivariate logistic regression.Disease history—At least one of the following diseases in early pregnancy: cardiopathy, diabetes, hypertension, epilepsy, anemia, phenylketonuria, mental illness, nephritis, hyperthyroidism, goiter, lupus erythematosus, or hepatitis.Occupational exposure—Employment as computer operator; radio, television, or communications technician; anesthetist; disinfection staff; nuclear medicine diagnostic doctor; nuclear physics researcher; distributor of agricultural products ; greenhouse, cotton, or fruit tree management; welding or smelting worker; printer; painter; dye worker; pesticide processing staff; rubber or plastics processing employee; cable manufacturing worker; or instrument manufacture or repair worker.A total of 171 cases were recruited from inpatients. We excluded 2 (1.17%) cases of stillbirth because we lost contact with the parents, 2 (1.17%) patients whose parents were distraught and unable to participate, and 3 (1.75%) patients whose parents were unwilling to be interviewed. Therefore, a total of 164 (95.91%) cases remained for analysis. A total of 401 hospital-based controls were selected, 328 (81.80%) of whom were included in the analysis. Among this group, 278 (84.76%) were inpatients and 50 (15.24%) were outpatients. The excluded controls comprised 40 (54.79%) children who were born outside their home province or whose birth mother was not a local resident, 24 (32.88%) who were unwilling to participate in this study, and 9 (12.33%) whose birth mother had died or could not be located.Among the 164 analyzed cases, 95 (57.93%) were boys and 69 (42.07%) were girls. The age range was 0.17 to 7 years, and the average age was 5.1 years. Among the cases, 58 (35.37%) had a ventricular septal defect, 28 (17.07%) had patent ductus arteriosus, 21 (12.80%) had tetralogy of Fallot, 15 (9.15%) had an atrial septal defect, 11 (6.71%) had pulmonary stenosis, and 31 (18.90%) had another type of CHD.We deleted all abnormal variables that had been identified in data structure analysis. Twenty-two factors were statistically significant after univariate conditional logistic regression analysis of all 41 research factors . Function transform was conducted on gestational age, father’s smoking status, father’s alcohol consumption, father’s age and mother’s age at this pregnancy, father’s and mother’s level of education, fetal order, gestational weeks until aware of pregnancy, number of previous pregnancies, and number of spontaneous abortions, but no nonlinear function was statistically significant. Dummy variables were also created for gestational age and parents’ ages at this pregnancy, and were reassigned by logically combining the category of younger age with that of older age for a similar OR. Grouping analysis of correlative variables was conducted for father’s and mother’s level of education, father’s and mother’s age at this pregnancy, history of spontaneous abortion, number of spontaneous abortions, fetal order, and number of previous pregnancies, maternal upper respiratory tract infection (URI), maternal fever, gynecologic examination, maternal infection, and use of medication by mother. As a result of this analysis, father’s level of education, father’s age at this pregnancy, history of spontaneous abortion, fetal order, maternal fever, and gynecologic examination were removed. Sixteen candidate factors were ultimately examined in multivariate analysis. The assignment and proportion of 41 research factors among cases and controls are presented in Table Multicollinearity diagnosis showed that there was good independence within the 16 candidate variables (Kaiser-Meyer-Olkin measure = 0.55). Seven putative environmental risk factors were significantly associated with local CHD after multivariate conditional logistic stepwise regression analysis . Partial correlation analysis was performed—and combined with professional knowledge—to ascertain whether there was interaction among the 7 factors, and to identify the first-order interactive variables, such as mother’s education level × number of previous pregnancies, maternal infection × maternal URI, maternal infection × maternal B-mode ultrasound examination, maternal infection × maternal mental stress. However, we did not identify any statistically significant variables that could be explained in light of the authors’ professional knowledge.Z value  to compare the relative importance of independent variables to dependent variables in the model: the larger the absolute value of Z, the greater the role of the variable. The results of multivariate analysis showed that the possible risk factors—ranked according to their influence on the occurrence of CHD, from strong to mild—were maternal mental stress, number of previous pregnancies, maternal infection, mother’s level of education, maternal URI, maternal B-mode ultrasound examination, and neonatal asphyxia or hypoxia. Detailed results are shown in Table Because the results of the PHREG procedure of the SAS software did not provide a standardized partial regression coefficient, we used the A hospital-based 1:2 matched case–control study was conducted to screen possible risk factors for CHD occurring in the Shandong Peninsula. Eligible cases and controls were selected according to strict criteria, and the area of coverage was specifically restricted to the Shandong peninsula. Ultimately, good results were obtained with this sample.It is very important to use appropriate modeling strategies in studies of etiologic association. To cite one example, when linear regression analysis is performed, nonlinear relationships must be considered. It is necessary to investigate various functional relations between factors and diseases by means of variable transformation, and to consider the possibility of interactions so as to guard against the chance that potential risk factors or modes of action might be neglected. Although we observed no statistically significant transformed variable form in this study, we did gain a number of valuable insights.Z = 3.20, P = 0.0014) in the occurrence of CHD, and that there was a dose–response relationship between them. This association was also observed in the case–control studies of Adams et al21 and Carmichael et al,22 but those studies relied on 3 questions to identify mental stress: 1) “Did anyone close to you die?” 2) “Did you or anyone close to you lose a job?”, and 3) “Were you or was anyone close to you divorced or separated?” A positive response to one of the questions was defined as positive mental stress. However, individuals’ mental responses to the same life event can differ greatly. Therefore, in the present study, mothers were asked not only about whether they experienced various stressful events, such as the above, during early pregnancy; they were also asked to indicate their subjective responses to these stressors. Two tiers of questions were designed to categorize maternal mental stress. The first tier asked if any of the following occurred during early pregnancy: 1) “Did anyone in your family suddenly die or fall severely ill?” 2) “Has there been family conflict?” 3) “Have your relations with colleagues or friends been stressful? 3) “Have you felt a great deal of pressure at work?” 4) “Did you have an accident?”, and 5) “Was a large amount of money stolen from your family?” If the response to one of these questions was affirmative, then a second tier question was asked: Was your mental response severe, mild, or absent? Although the role of maternal stress needs to be validated by additional studies, and the biologic mechanisms by which maternal stress causes CHD require elucidation, we strongly suggest that mental healthcare for pregnant women be augmented, especially during early pregnancy.We observed that maternal mental stress during early pregnancy was the most important factor . Ferenca et al25 found that a history of miscarriage was associated with an increased risk for tetralogy of Fallot. Therefore, we should strengthen obstetrical care for women who have had spontaneous abortions by implementing regular health counseling and testing to decrease the incidence of pediatric CHD.The number of previous pregnancies and number of spontaneous abortions were statistically significant in univariate analysis, but only number of previous pregnancies was significant in multivariate analysis . Multiparity has been limited in China since the 1980s—when the family planning policy was implemented—which suggests that the association we observed is due to spontaneous abortions. Chinn et al26 TORCH microorganisms can be easily transmitted to the fetus throughout the pregnancy via the imperfect placental barrier, especially in cases of primary infection during early pregnancy. In 1941, Gregg was the first to describe the relation between maternal rubella virus infection early in gestation and congenital rubella syndrome in offspring.27 Since then it has become widely known that maternal microorganism infection during pregnancy can result in the birth of offspring with CHD28–31; hence, much attention has been given to the prevention of TORCH infections in pregnancy. In our study, maternal infection  and maternal URI  were associated with CHD. The infecting microorganisms that interviewees self-reported included rubella virus, toxoplasma gondii, cytomegalovirus, hepatitis virus, and influenza virus. We did not analyze the influence of each microorganism on CHD because of the limited sample size. URI in the first trimester of pregnancy may be associated with an increased risk for birth defects in offspring. However, these findings should be interpreted cautiously.32 Most pregnant women cannot distinguish between a URI and influenza, so it is impossible to eliminate the possibility that influenza may have been misclassified as URI. In addition, Koro'lkova et al33 found that Coxsackie B serotypes were associated with CHD. People often take medication for such infections; however, they often cannot recall the drug types and names. Therefore, as compared to collecting information on medication use, it is likely to be easier to ascertain that a participant has a history of infection or URI. Although medications taken during early pregnancy were not analyzed in the multivariate regression model, effects due to drug use cannot be ruled out.TORCH infections—Toxoplasma gondii, Other microorganisms (like syphilis), Rubella virus, Cytomegalovirus, and Herpes viruses—can cause severe birth defects during gestation.21,34; others have found such an association.35 We noted that the occurrence of CHD was inversely associated with the mother’s education level , and that there was a dose–response relationship between them. We suspect that mothers with a high level of education were better able to care for themselves, to obtain information on reproduction and pregnancy, and to secure access to health service, thereby indirectly reducing the occurrence of CHD. These findings also highlight the need to improve the healthcare and educational opportunities for women of childbearing age, particularly for those with less formal education.Some studies showed no association between the mother’s education level and CHD24,25,36; however, we did observe an association with B-mode ultrasound examination. It is uncertain whether the maternal B-mode ultrasound examination caused the increasing occurrence of CHD, or if CHD and/or other diseases resulted in the ultrasound examination. We observed that the association was weak for mothers with abnormal findings before the ultrasound examination. We suspect that the association resulted from bias and that the B-mode ultrasound examination was not a cause of CHD, although further study is necessary to resolve this question.There was no evidence of an association between CHD and maternal exposure to ionizing radiation or video display terminals37–40 Similar results were obtained in South America41 and Peru.42 The physiological, pathological, pathogenic, and clinical features of heart and pulmonary circulation in related diseases in high-altitude areas were described several decades ago,43 but many unanswered questions still exist with respect to causality. Miao et al44 ascribed the increase in CHD to postnatal factors, which means that CHD is due to prolonged postnatal hypoxia. We examined whether neonatal asphyxia or hypoxia occurred at the time of birth . It is very difficult, but nevertheless important, to determine whether CHD caused neonatal asphyxia or hypoxia, or if neonatal asphyxia or hypoxia resulted in the postnatal occurrence of CHD. We believe the latter is more likely because the Shandong Peninsula is not in a plateau region. If a relation is confirmed, it would indicate that short-term neonatal asphyxia or hypoxia is an important environmental risk factor for CHD occurring after birth.Many epidemiologic studies in China have indicated that CHD is more likely to occur at high altitude than that at sea level. The lower atmospheric oxygen tension present at high altitude was associated with a higher prevalence of CHD—mainly patent ductus arteriosus and atrial septal defects.There were limitations in our study. First, a hospital-based case–control study has inherent weaknesses. Hospital-based cases do not represent the total distribution of CHD occurring in the local population. Usually, cases presenting for treatment in hospitals are individuals with more serious illnesses, more evident symptoms, or higher socioeconomic status. This generally results in some selectivity of hospitalized patients and, because there are various types of CHD, Berkson bias is unavoidable. In addition, it is likely that some potential cases died at a young age and went undetected, and that CHD went undiagnosed in some patients after birth because of the characteristics of the disorder and limitations in diagnosis and treatment. Furthermore, it is difficult to ensure appropriate selection of hospital-based controls. In our study, controls were not randomly selected from all eligible patients in the same medical institutions as the cases; rather, the 2 eligible and available controls whose time of presentation at hospital was closest to that of the case were selected. Although we conducted a matched case–control design, the comparability of cases and controls cannot be guaranteed; however, efforts were made to reduce selection bias. Namely, in the selection of controls, inpatients (84.76%) were preferred; the remaining controls were outpatients (15.24%). We attempted not to select patients who had come for a health checkup or other reasons. If a control were to have undetected CHD, then the apparent OR would be an underestimation of the true risk.Secondly, we collected information by means of self-reporting, which is easier to implement and requires less manpower, material, and financial resources; however, it can result in recall bias. The time interval between the exposures of interest and the interview, the age, and cultural and educational background of the respondents can all affect the validity of the responses. Fortunately, the matching design, to a certain extent, offsets this exposure misclassification. Recall bias is difficult to control for when the recollection effects between cases and controls differ. Ordinarily, the parents of children with a congenital abnormality are more sensitive to abnormal or adverse pregnancy outcomes. Thus, they may exaggerate or overestimate exposures to harmful factors during pregnancy, even subjectively establishing a false association. For example, when asked, “Did anyone in your family suddenly die or fall severely ill?” cases may consider more distant relatives, or a more distant past, than controls, and may magnify their mental responses to stressful events. The cases may also magnify exposure to radioactive medical examination, microorganism infection or URI, vaccination or drug use, occupational history, and some lifestyle factors  during and before pregnancy, even if these did not take place before the occurrence of CHD. This would ultimately lead to an overestimation of risk. Masking was used in this investigation, and all interviewers were uniformly trained before the formal interview. Therefore, we believe that investigation bias was minimal in the present study.Thirdly, the causes of CHD are multifactorial, and the types of CHD are varied and complex. It was therefore impossible, in the present study, to include all the suspected risk factors for CHD. Although some types of CHD have much in common, specific types of CHD result in particular consequences. Moreover, a very large, diverse set of questions on putative risk factors could affect the statistical power of the analysis. To cite one example, in the original data collection for the study, age at pregnancy was broadly classified . However, there were relatively few parents aged <20 or ≥35 years. The absence of detail for the 20–35-year-old age group might explain why there was no significant difference in age between cases and controls. In addition, the limited number of age groups may have resulted in a failure to control for confounding by mother’s age at this pregnancy.Because of these limitations, the findings need to be interpreted cautiously and etiologic association must not be inferred. Nevertheless, this study offers information to assist in developing guidelines for local CHD prevention. The results strongly suggest that: 1) government, society, and families should pay more attention to the mental health of pregnant women, especially during early pregnancy, and should take all practical measures to create a relaxed living and working environment by reducing or eliminating all types of mental stress; 2) women should be offered regular and standardized health counseling and testing during pregnancy—such as TORCH active infection screening during early pregnancy, TORCH series IgM antibody testing, and DNA testing through umbilical cord blood—and should consider vaccination or pregnancy termination, if necessary; 3) women should guard against URI, refrain from taking unnecessary medication in pregnancy, and comply with doctors’ guidance and prescriptions; 4) the government should develop health education materials and communication strategies targeted at women of childbearing age, especially those with less formal education, to enable them to better care for themselves and seek health services; and 5) improve procedures and techniques to guard against neonatal asphyxia or hypoxia.


Using an allele score that combined all four SNPs as the IV, the estimated causal effect was OR 1.16 , whilst it was 0.94  and 0.93  when using an upstream  and a downstream allele score , respectively. 25-OHD levels were inversely associated with CRC risk, in agreement with recent meta-analyses. The fact that this finding was not replicated when the MR approach was employed might be due to weak instruments, giving low power to demonstrate an effect (<0.35). The prevalence and degree of vitamin D deficiency amongst individuals living in northerly latitudes is of considerable importance because of its relationship to disease. To elucidate the effect of vitamin D on CRC cancer risk, additional large studies of vitamin D and CRC risk are required and/or the application of alternative methods that are less sensitive to weak instrument restrictions.Vitamin D deficiency has been associated with several common diseases, including cancer and is being investigated as a possible risk factor for these conditions. We reported the striking prevalence of vitamin D deficiency in Scotland. Previous epidemiological studies have reported an association between low dietary vitamin D and colorectal cancer (CRC). Using a case-control study design, we tested the association between plasma 25-hydroxy-vitamin D (25-OHD) and CRC . To determine whether plasma 25-OHD levels are causally linked to CRC risk, we applied the control function instrumental variable (IV) method of the Mendelian randomization (MR) approach using four single nucleotide polymorphisms  previously shown to be associated with plasma 25-OHD. Low plasma 25-OHD levels were associated with CRC risk in the crude model (odds ratio (OR): 0.76, 95% Confidence Interval (CI): 0.71, 0.81, p: 1.4×10 We aimed to recruit all incident cases (1999–2006) of adenocarcinoma of colorectum presenting to surgical units in Scotland (18–79 years old). Exclusions were patient death before ascertainment, patient too ill to participate, recurrent cases, or patient unable to give informed consent due to learning difficulties or other medical conditions. We recruited about 40% of all incident cases in Scotland over the study period. During the same period controls were drawn randomly from a population-based register  and invited to participate. Participation rates among those approached were approximately 58% for cases and an estimated 57% for controls. More than 99% of the study participants were white Caucasian (see http://www.foodfrequency.org), which consisted of 150 foods and the individuals were asked to describe the amount and frequency of each food on the list they have eaten a year prior to diagnosis or recruitment. Further information about the questionnaires were presented in detail previously The subjects completed one questionnaire with lifestyle and cancer information and they were asked to report their status one year prior diagnosis or recruitment, including information about their general medical history, physical activity, smoking status, intake of any regular intake of aspirin and NSAIDs, height, weight and waist circumference were recorded. Additionally a semi-quantitative food frequency questionnaire  was completed by participants (http://www.sehd.scot.nhs.uk/), The criteria for high family history risk of colorectal cancer are: 1) at least three family members affected by colorectal cancer or at least two with colorectal cancer and one with endometrial cancer in at least two generations; one affected relative must be <50 years old at diagnosis and one of the relatives must be a first degree relative of the other two; or 2) presence of the HNPCC syndrome; or 3) untested first degree relatives of known gene carriers. The criteria for moderate risk are: 1) one first degree relative affected by colorectal cancer when aged <45 years old; or 2) two affected first degree relatives with one aged <55 years old; or 3) three affected relatives with colorectal or endometrial cancer, who are first degree relatives of each other and one a first degree relative of the consultant. Individuals that do not fulfil all the above criteria are classified as low family history risk (Scottish Executive cancer guidelines). For this analysis family history was coded as low vs. medium/high family history of CRC.Family history risk was determined according to the Scottish Executive cancer guidelines (The liquid chromatography-tandem mass spectrometry (LC-MS/MS) method was used to measure 25-hydroxyvitamin D3 and D2. This paper presents the 25-OHD ; however, most of our samples contained no D2 (<3 ng/ml). The lower limit of detection with the LC-MS/MS method was 4 ng/ml for D3 DNA samples were accurately quantified by Pico-GreenTM and quality controlled prior to dispatch. Genotyping was undertaken using TaqMan in the Wellcome Trust Clinical Research Facility (WTCRF) in Edinburgh. 2,000 subjects for the rs2282679 were genotyped as part of an array-based candidate gene approach, using the Illumina Infinium I Custom array platform and performed by Illumina (San Diego). Case and control DNA samples were stored, genotyped and analysed in the same way. In addition to avoid potential systematic batch-to-batch variation or bias, samples were anonymised as to affection status and were randomly distributed within plates. Data were subject to Illumina or WTCRF quality control procedures. Assumptions of Hardy-Weinberg Equilibrium (HWE) were tested using a chi-squared test.2, continuous), regular NSAID intake (yes vs. no), family history (low vs. medium/high) of cancer and physical activity . We also tested the association after sex, stage of cancer at diagnosis (AJCC), presence of symptoms and time between diagnosis and recruitment stratification. In addition the association between CRC and rs2282679, rs12785878, rs10741657 and rs6013897 was tested. Dataset for this analysis was larger, and it comprised all SOCCS study participants for whom genotyping of selected SNPs was successful . We also tested the interaction between genotype and vitamin D plasma levels on CRC by comparing a model with and without an interaction term between the two variables, using a likelihood ratio test. Assumptions of Hardy-Weinberg Equilibrium were tested using a chi-squared test.The statistical package used was Stata version 11.0 . Participants were divided into quintiles based on the combined distributions of cases and controls. Logistic regression models were used to estimate the strength of association between CRC risk and vitamin D plasma levels. The associations were tested in three logistic regression models . Model I was corrected for age and sex and Model II was corrected for age, sex, Carstairs Deprivation Index, energy (MJoules/day), smoking , body mass index  and a binary outcome Y (CRC). The first stage of the control function is a linear regression of the intermediate phenotype (X) on the instrument(s) (Z), which generates predicted values for the intermediate phenotype. The second stage is a logistic regression of the outcome (Y) on the predicted values of the intermediate phenotype including the estimated residuals from the first-stage linear regression in the second-stage logistic regression Methods S1).To estimate the causal odds ratio we applied the control function IV estimator for a 3-level categorical instrument Z coded 0, 1, 2 (SNP) a continuous intermediate phenotype X (plasma 25-OHD−14), after adjusting for age and sex  and after adjusting for age, sex, Carstairs Deprivation Index, energy, smoking, BMI, regular NSAID intake, family history of cancer and physical activity  (−13) than women  (Table S2). The 25-OHD CRC association was similar for early  versus late AJCC stage . Furthermore, the 25-OHD CRC association was weaker for those CRC patients that had no symptoms at the time of the diagnosis , when compared to those with mild  or severe symptoms . Finally, the 25-OHD CRC association was similar for those CRC patients that were recruited soon after diagnosis , when compared to those who were recruited later .Colorectal cancer risk was associated with lower levels of plasma 25-OHD in the crude model (Odds ratio (OR): 0.76, 95% Confidence Interval (CI): 0.71, 0.81, p: 1.4×106×10−12) Table 1.There was no evidence for departure from HWE for all four SNPs: rs2282679 p-value = 0.25, rs12785878 p-value = 0.78, rs10741657 p-value = 0.07 and rs6013897 p-value = 0.52. The A allele of rs2282679 and the T allele of rs12785878 were associated with higher levels of plasma 25-OHD Table 2.Overall there was no evidence of an association between any of the four SNPs and CRC risk Table 3.Table S6) and, as expected Before applying the MR approach we assessed the IV assumptions. The first (that genotype is associated with the phenotype) was fulfilled since we selected four SNPs that were found to be linked to plasma 25-OHD levels in a pooled meta-analysis of Genome Wide Association Studies .Using the rs2282679 as the IV, the estimated causal effect of plasma 25-0HD on CRC risk was 0.94 , and the F-statistic for the rs2282679 from the first stage of the IV analysis was 15.80 in the age and sex adjusted analysis Table 4.Furthermore, we combined these four SNPs to form three allele scores: 1) one allele score that combined all four SNPs, 2) an upstream allele score that combined the SNPs rs12785878 and rs10741657 and 3) a downstream allele score that combined the SNPs rs2282679 and rs6013897. We then used this allele scores as the IV. The causal effect for the overall allele score was 1.16 , for the upstream allele score was 0.94  and for the downstream allele score was 0.93  Table 4.In this study, low levels of plasma 25-OHD were associated with a higher risk of CRC in the whole sample and after stratification for sex, tumour stage and severity of symptoms at presentation. These results are in accordance with two recent meta-analyses of serum or plasma prospective studies GC gene, which encodes a vitamin D binding protein that binds and transports vitamin D (DHCR7 gene that encodes the enzyme 7-dehydrocholesterol (7-DHC) reductase, which converts 7-DHC to cholesterol. 7-DHC is a precursor of vitamin D3. Mutations in the DHCR7 may lead to a decreased activity of the 7-DHC reductase and therefore to high levels of 7-DHC and vitamin D3  CYP24A1 gene, which encodes an enzyme that initiates the degradation of 1,25(OH)2D CYP2R1and CYP24A1 is limited and not replicated in other candidate studies The A allele of rs2282679 and the T allele of rs12785878 were associated with higher levels of plasma 25-OHD. These results are in accordance with a GWAS investigating genetic determinants of vitamin D deficiency itamin D Figure 1None of the four SNPs were associated with CRC risk, although we found an interaction between 25-OHD levels and rs10741657. The results of the MR analysis did not support a causal relationship between plasma 25-OHD and CRC risk. Although not significant, the inverse relationship was noted when rs2282679 or rs10741657 were used as instrument, but not when rs12785878 or rs6013897. The results remained inconsistent when the three allele scores of the four SNPs was used. The fact that the inverse association that was observed when we applied the conventional epidemiological methods was not replicated when the MR approach was used might be due to several reasons. It is possible that unmeasured or latent variables confounded the associations and there is no true effect of vitamin D on CRC. An alternative explanation is that there might be reverse causality between vitamin D and CRC, given that the plasma of the cases was collected after diagnosis: it cannot be excluded that low plasma 25-OHD is the consequence of disease or a result of patients being bedbound and lacking the exposure to sun. However, when we looked at cases with very mild or no symptoms or cases at the very early stages of the disease we still observed an inverse association between 25-OHD levels and CRC. In addition, given the biological potential of vitamin D having a causal link with cancer, factors that affect the performance of the IV estimators might also explain these findings.Major limitations of conventional instrumental variable approaches result from the strict assumptions that need to be satisfied for method to be reliable. It is true that genotype is associated with phenotype, however, SNPs that have been used as instruments are only weakly associated to phenotype and explain only a small portion of trait variance. While we tested for common confounders, it is possible that hidden confounding from unmeasured variables affects the analysis. While we see no association between genotype and the outcome, weaker pleiotropic links cannot be excluded with certainty.We are currently working on new instrumental variable methods for assessing causality between 25-OHD concentrations and CRC, based on the platform for the Bayesian analysis of complex statistical models using Markov chain Monte Carlo methods. This method improves on the classical Mendelian Randomisation approach as it allows for pleiotropic links between components of the model, enables easy inclusion of other covariates and does not depend as much on the strength of the instruments.The wide application of the genome wide association studies (GWAS), has allowed for the MR studies to become more feasible now, as common SNPs linked to various intermediate phenotypes have been identified Table S11 for a review of the 11 MR studies published in 2011). Using simulations presented in the paper of Pierce et al According to a recent study on the power and sample size requirements of MR studies based on the strength of the instruments, found that MR studies will require large (n>1000) and often very large (n>10000) sample sizes to draw causal conclusions that are statistically significant This study shows that higher plasma 25-OHD levels are associated with a lower CRC risk, a finding that is consistent with recent meta-analyses of prospective studies. However, this finding was not replicated when the MR approach was employed. This finding might be due to a lack of a true effect of vitamin D on CRC or due to reverse causation. It may also be due to weak instruments and limited statistical power. The lack of power is a common characteristic of many MR studies and therefore a careful selection of instruments plus an adequate sample size are deemed necessary for this method to be able to make causal conclusions. Given the extent of vitamin D deficiency among individuals living in high latitudes, a large consortium of similar vitamin D and CRC studies and/or the application of alternative methods that are less sensitive to weak instrument bias Table S1Information about the SNPs that were used as Instrumental variables in the MR analysis.(DOC)Click here for additional data file.Table S2Logistic regression analysis for the association between plasma 25-0HD on colorectal cancer risk after sex stratification.(DOC)Click here for additional data file.Table S3Logistic regression analysis for the association between plasma 25-0HD on colorectal cancer risk after stage stratification.(DOC)Click here for additional data file.Table S4Logistic regression analysis for the association between plasma 25-0HD on colorectal cancer risk after stratification for presence of symptoms.(DOC)Click here for additional data file.Table S5Logistic regression analysis for the association between plasma 25-0HD on colorectal cancer risk after stratification based on the time between diagnosis and recruittment (TDR).(DOC)Click here for additional data file.Table S6Distribution of possible confounding factors and the instruments.(DOC)Click here for additional data file.Table S7Wald/ratio instrumental variable estimator of the causal odds ratio for the effect of plasma 25(0H)D on colorectal cancer risk.(DOC)Click here for additional data file.Table S8Two stage instrumental variable estimator of the causal odds ratio for the effect of plasma 25(0H)D on colorectal cancer risk.(DOC)Click here for additional data file.Table S9Multiplicative structural mean models instrumental variable estimator of the causal odds ratio for the effect of plasma 25(0H)D on colorectal cancer risk.(DOC)Click here for additional data file.Table S10Logistic structural mean models instrumental variable estimator of the causal odds ratio for the effect of plasma 25(0H)D on colorectal cancer risk.(DOC)Click here for additional data file.Table S11Review of the characteristics of the MR studies published in 2011.(DOC)Click here for additional data file.Methods S1Information about the following Instrumental Variable estimators: Wald (ratio) estimator, Two stage least squares estimator, Multiplicative structural mean models, Logistic structural mean models.(DOC)Click here for additional data file.


Congenital anomalies have been found more often in children with cancer than in those without. Rib abnormalities (RAs) have been associated with childhood cancer; however, studies have differed in the type of RAs and cancers implicated.Rib abnormalities were assessed predominantly by X-ray in a hospital-based case–control study.vs controls with RAs after controlling for age and sex, specifically for acute myelogenous leukaemia, renal tumours, and hepatoblastoma.There was a significant difference in the number of cases The results of this study support previous reports that there is an association of rib anomalies with childhood cancer. Multiple studies have demonstrated an association between morphological abnormalities and paediatric cancer  patients treated at the University of Minnesota Medical Center—Fairview in Minneapolis, MN for malignancy during 2003–2009. Cases must have been diagnosed between the ages of 0–19 years and had been imaged during the study period. Children with a known syndrome  identified through our database were excluded; we expect that only very minimal number of syndromic cases were missed. Controls were randomly selected paediatric patients who received a chest X-ray at Fairview Ridges Hospital in Burnsville, MN during June and October of 2003–2008. Controls were chosen from this community hospital as they more likely represent the general Twin Cities paediatric population. Indications for chest X-rays in controls included asthma or shortness of breath, bronchitis, chest pain, possible pneumonia, trauma, and others . The study was approved by the University of Minnesota Institutional review board.κ statistic) of the abstraction tool. The initial abstraction tool showed substantial agreement for the availability of images (Kappa (κ)=1.00), rib number (κ=0.75), and bifid ribs (κ=0.79) (κ=0.57) and cervical ribs (κ=0.52). Improvements to the abstraction tool included clarification of the definition of which images were considered not evaluable due to the inability to clearly visualise the C7 and L1 vertebra. After the original review of images, two radiologists analysed all positive images. Of the 82 images scored positive by the resident, the radiologists found 77 positive images indicating a 94% agreement. A complete reanalysis of the radiologists’ data found no substantial differences compared with the resident (data not shown).Images were reviewed for numerical and structural RAs according to previously described scoring methods ((κ=0.79) . Moderatpost hoc evaluation of a random sample of 100 images by two radiologists to determine interrater reliability of availability of images (κ=1.0), evaluability of images (κ=0.80), and the presence of RA (κ=0.85). The high level of agreement between the radiologists and radiology resident provided confidence to allow the resident's evaluations to stand in the analysis. Blinding reviewers to case status was not entirely possible; however, they were not made aware of the study's hypothesis until completion of data collection.Using the improved abstraction instrument one radiology resident reviewed each radiograph, followed by χ2-test was used to assess categorical data differences between cases and controls. Dichotomous variables were created for normal or abnormal ribs , rib number , cervical and bifid ribs. Only one rib synostoses/fusion or segmentation defects were detected and so these were not analysed. All cases as well as individual cancer types with greater than five RAs were analysed. Unconditional logistic regression was used to calculate the ORs and 95% CI for RAs adjusting for age and sex.Pearson's Sensitivity analyses were completed to examine the possibility of bias introduced from the selection of cases and controls; these included analyses with each indication for X-ray in controls dropped in turn, exclusion of all individuals who resided outside the state of Minnesota, restriction by image type, and separate analyses of paediatric BMT and haematology/oncology patients. All statistical analyses were performed using SAS Version 9.2 software .n=409, BMT, n=216) and 1499 eligible controls (P<0.0001). Controls had a higher percentage of X-rays (99.6% vs 88%) and cases had a higher percentage of available CTs (12.0% vs 0.2%)  . Study pvs 0.2%) .P-value=0.008) (Rib number assessed as an integer differed in cases and controls (Fisher's exact e=0.008) . When cae=0.008) . A similPresence of any RA was also borderline significant in the crude analysis , but significant after adjustment  . Removinn>15) are noted in crude=14.14, 95% CI: 2.34, 88.83, ORadjusted=14.43, 95% CI: 2.34, 88.83). All other cancer types did not show a significant association with RAs . Excluding all individuals living outside the state of Minnesota or X-ray only images greatly reduced the number of analysable cases making the associations essentially null. Interestingly, when RAs and rib number were separated into two ethnic categories (Caucasian and non-Caucasian) a statistically significant result was noted for non-Caucasians  but not in Caucasians alone .et al and We detected a moderate but fairly consistent association of RAs and childhood cancer, which remained despite several sensitivity analyses that we performed to compensate for limitations. The findings further appeared to be strongest in AML, renal tumours, and hepatoblastoma. Our results offer partial confirmation of three previous studies on the topic. The US study by The hospital-based case–control study design had several limitations. The study population was created from a convenience sample which to some extent limited our analyses. Case and control selection has the potential to introduce bias. Cases in our study were obtained from a tertiary care centre. Cases were likely unaware of RAs and therefore unlikely to be differentially ascertained based on this basis. The underlying cohort that gave rise to the cases in our study would be difficult to define. In an attempt to best replicate the cohort, controls were obtained from a hospital-based clinic to better represent the paediatric population of Minnesota, but we cannot rule out bias due to mismatch between sources of cases and controls. Controls were included in our study for a variety of conditions to dilute any effect of one condition increasing the likelihood of obtaining a chest X-ray due to having a RA.Our results indicate a modest but fairly robust association between RAs and paediatric cancer generally in line with other findings. Particularly, RAs were associated with increased odds of the individual cancer types AML, renal tumours, and hepatoblastoma. Paediatric cancer aetiology remains an elusive area of research with great need for better understanding. Prospective studies examining the genetics of RAs and childhood cancer may provide insight into the pathways leading to the development of paediatric cancer. The existence of common genetic and/or developmental origins in congenital anomalies and childhood cancer is a rich area for future investigation.


Sasang typology based on the Temperament and Character Inventory (TCI) in a Korean adult clinical sample. A total of 97 adults completed the Korean version of the TCI. The participants were classified as one of three traditional Korean Sasang types  by three specialists in Sasang typology. The seven dimensions of TCI were compared between the different Sasang types using analysis of variance (ANOVA) and profile analysis. There were no significant differences in age, gender and education across the Sasang types. The TCI profile for each of the Sasang types was significantly different . There were significant differences in the temperament dimensions of Novelty Seeking  and Harm Avoidance  among the Sasang types. The Novelty Seeking score of the So-Yang type (31.90 ± 9.87) was higher than that of the So-Eum type  while the So-Eum type (44.64 ± 8.47) scored higher on the Harm Avoidance score compared to the So-Yang type . There were no significant differences in the temperament dimension of Reward Dependence and Persistence, and the three character dimensions of Self-Directedness, Cooperativeness and Self-Transcendence. Results demonstrated distinct temperament traits associated with traditional Korean Sasang types using an objective biopsychological personality inventory. With further study, the Sasang typology may lead to enhanced clinical safety and efficacy as part of personalized medicine with traditional medicine.The purpose of this study was to examine the biopsychological personality profiles of traditional Korean  Sasang typology, as a traditional Korean medical typology, epitomizes personalized medicine based on both physical and psychological characteristics and features, and shares much similarity with the Western academic tradition [Sasang typology not only encompasses such a similar constitutional classification system, but also shares a similar conceptual basis with Eysenck's description of introversion-extroversion and neuroticism [Sasang typology also appears to be related to Hippocrates' concept of the four humors [Current changes in medicine have led researchers to focus on preventive, predictive and personalized medicine. Personalized medicine represents a form of individualized medicine wherein medical treatment is tailored to the individual to maximize efficacy and safety. A diverse array of research is being conducted utilizing genetic characteristics following the Human Genome Project . Sasang radition –9. For iradition  and Shelradition  identifiroticism , 3, 12. r humors , 14.Sasang typology, originally theorized by Lee Je-ma [Sasang typology, one's physical constitution is classified according to the traits of an individual's mind and body, with the implication that one's sensitivity and response to certain drugs can be different depending on one's Sasang type [Sasang types: Tae-Eum, So-Eum, So-Yang and Tae-Yang. The So-Yang type, for instance, is a sharp and clean-looking person who is extroverted, hot-tempered and interested in the outside world. The So-Eum type is an inactive, prudent, narrow-minded, negative, organized, nervous and resolute person.ee Je-ma  is widelang type . There aSasang types has revealed a variety of psychological profiles [Sasang typology, neuroticism and extroversion were determined to be important personality factors in discriminating between So-Yang and So-Eum types [Sasang types [Research focusing on the psychological and personality characteristics of different profiles . For exaprofiles , 3, whilum types  and Costum types , 17. Theng types , 14.Sasang typology [Sasang typology from a biopsychological standpoint.Activity versus inactivity as personified by the So-Yang and So-Eum types share similarities with Gray's personality theory. In other words, Gray's personality theory is based on the principle that individual differences in personality reflect the variation in sensitivity and responsiveness to punishment and frustrative non-reward, and reward and relieving non-punishment, the behavioral inhibition system (BIS) and the behavioral activation system (BAS), respectively , 19. Chatypology . All of The Temperament and Character Inventory (TCI) originally developed by Cloninger, is an assessment tool based on such a biopsychological personality model that may reflect the BAS/BIS concept –21. ThisIn contrast, character factors appear to mature in adulthood and affect personal and social effectiveness through insight learning about self-concepts. Character dimensions that are based on theories of social, cognitive and personality development are Self-Directedness (SD), Cooperativeness (C) and Self-Transcendence (ST), each referring to individual differences in self-concepts, goals and values. In contrast to temperament, aspects of character are thought to be influenced by social learning along with genetic factors and to mature in stages throughout the lifespan , 24, 25.Sasang typology in a clinical sample of community-dwelling adult men and women. Our research sought to corroborate results of an earlier study [Sasang types were confirmed by three clinical specialists are included. Earlier research distinguished between Sasang types by using a self-report questionnaire, thereby making direct comparison with reactivity to medication difficult [Sasang-based medical regimen, we hope that a guideline for use of herbal medication will be provided for future reference.Here, we examined the temperament and character profiles measured by the TCI based on er study  that fouifficult . By usinSasang types with the goal of providing a scientific and empirical basis of Sasang medicine. Our approach passed the IRB of the Korea Institute of Oriental Medicine, and participants completed a written consent form.This research is part of the Lee Je-Ma Project, a national research study investigating the characteristics of Sasang type for 50 days or more, (iii) did not manifest significant medication adverse events as indicated in the medical records, (iv) demonstrated clear improvement in their chief complaints and pre-existing symptoms and/or exhibited a unique improvement pattern and (v) for whom there existed clear documentation of medication treatment response in the medical chart  who were younger than 20 years of age or older than 69 years of age, (ii) who did not provide a mailing address and/or contact information or (iii) individuals with religious affiliations were excluded from the study. A total of 298 individuals were mailed the TCI, and 97 individuals returned the questionnaire in 2008. The prevalence of the Tae-Yang type is historically found to be extremely low (0.03–0.1%) [n = 41), So-Eum (n = 25) and So-Yang (n = 31) Sasang types were statistically analysed. Participants were selected in 2008 from a pool of 11 730 outpatients who visited a hospital for Korean Oriental Medicine between June of 1996 and May of 2004 in several major cities of Korea such as Kwangju, Jeonju and Seoul. Among these participants, 1156 individuals who met all of the following inclusion criteria composed the initial sample pool: (i) made a minimum of five outpatient visits, (ii) underwent pharmacological management prescribed for the particular al chart . Clinica03–0.1%)  and onlynot at all to 4 = very true). The Korean version of the questionnaire was standardized and validated in 2007 and demonstrated validity and reliability. Each of the dimensions of the TCI is assessed as the sum of scores on three to five subscales measuring 29 more specific traits that define the temperament and character dimensions. For example, Harm Avoidance includes anticipatory worry and pessimism versus uninhibited optimism (HA1), fear of uncertainty (HA2), shyness with stranger (HA3) and fatigability versus vigor (HA4). Overall internal consistency as measured by Cronbach's alpha was 0.871. Cronbach's alpha for the NS, HA, RD, P, SD, CO and ST scales were 0.829, 0.857, 0.814, 0.821, 0.865, 0.758, and 0.899.The Korean version of the Temperament and Character Inventory-Revised-Short (TCI-RS)  is a 140Sasang types  were tested using Analysis of Variance (ANOVA) for continuous variable (age) and Fisher's exact tests for categorical variables . Profile analysis such as test of parallelism and flatness was performed to test the difference of the TCI profile for each Sasang type. Analyses of Variance (ANOVAs) were conducted to test between-group differences in TCI scores across the three Sasang types. The data are represented as means and standard deviations. All analyses were conducted using SPSS 16.0.1 for Windows .Demographic differences between Sasang types.Results are divided into two sections. The first describes the background characteristics of the sample, and the second describes the TCI temperament and character profiles across the three The mean age, gender composition and educational attainment level are described in Sasang types, F = 1.94, P = .149, χ2 = 0.871, P = .647 and χ2 = 0.764, P = .682, respectively.The mean age of the entire sample was 47.6 ± 10.5 years. There were no significant differences in age, gender composition and level of education between the three Sasang types. The TCI temperament score profile of the So-Yang, Tae-Eum and So-Eum types were significantly different. The profile of TCI temperament dimension, such as NS, HA, RD and P was not flat . As for the parallelism of TCI temperament profile with the interaction of Sasang type were significantly different . Sasang types showed significant differences in the Novelty Seeking, F = 3.43, P = .036, and in the Harm Avoidance, F = 5.43, P = .006, scales of the TCI. Dunnett's post-hoc tests revealed that the So-Yang type (31.90 ± 9.87) scored higher on the NS scales compared to the So-Eum type  and lower on the HA scale (35.16 ± 11.50), compared to the So-Eum type . There were no other significant differences between Sasang types in the other 5 TCI dimensions. F = 4.06, P = .02 and F = 7.59, P = .001. More specifically, the So-Eum type scored higher on the HA1 (10.96 ± 3.69) and HA2 (12.40 ± 2.36) subscales when compared to the So-Yang type (7.61 ± 4.26 and 9.61 ± 3.14). Such differences make intuitive sense, based on the traits attributed to each Sasang type. In addition, the difference between Sasang types on the NS4 (Disorderliness) subscale approached statistical significance, F = 2.98, P = .056, with So-Yang type (6.48 ± 3.39) scoring higher compared to the Tae-Eum type (4.63 ± 2.95).To further explore these dimensions, subscales of the NS and HA scales were analysed . A signiSasang typology of traditional Korean medicine was examined. According to our hypothesis, distinct temperament and character profiles would emerge for the different Sasang types as indicated on the TCI [In the current study, the relationship between objective personality theory as described by Cloninger in his biosocial model  of tempe the TCI .Sasang types, especially between the So-Eum and the So-Yang types. The So-Yang type, exhibiting contrasting features from the So-Eum type, scored higher on the Novelty Seeking scale and lower on the Harm Avoidance scale of the TCI. As based on such a TCI profile, they can be described as quick-tempered, excitable, impulsive and vigorous [Sasang types [The results demonstrated that the TCI temperament dimensions of Novelty Seeking and Harm Avoidance were particularly important in distinguishing between the three vigorous . The So-vigorous . Such reng types .Sasang typology, as based in mind-body medicine, can serve as a scientific basis for providing personalized and integrative medicine, and the importance of considering both physical traits and psychological characteristics in tailoring medical interventions.Looking more closely at the subscales of the NS and HA dimensions, the fact that the So-Eum type scored significantly higher on the HA1 (Anticipatory worry and pessimism versus Uninhibited optimism) and HA2 (Fear of Uncertainty) compared to the So-Yang type portrays them as pessimistic worriers who tend to anticipate harm and failure and experience difficulty tolerating uncertainty. Such temperament descriptions also coincide with Lee Je-ma's original theory that describes the So-Eum type as negative, nervous and mild. Such corroborated empirical findings support the argument that Sasang typology encompasses prescription guidelines for type-specific medical herbs for optimal efficacy and safety based on one's Sasang type that has accumulated through the 5000-year history of clinical experiences [Sasang typology are provided in Sasang type are not used for another Sasang type. For individuals who are low in NS and high in HA , ginseng may be quite effective. However, clinicians may consider adverse treatment effects of ginseng for individuals who are high in NS and low in HA . The eriences , 28. KeySasang typology. As in previous research, differences were found in the NS and HA dimensions, two temperament dimensions which are presumed to have a genetic and anatomical basis and can influence the clinical outcomes [Sasang types in the character dimensions, which are presumed to be able to change over time. This lends support, albeit indirectly, for the argument that the Sasang typology demonstrates longitudinal stability in terms of temperament and can be considered as biopsychological in nature. More specifically, NS and HA appear to be theoretically related to Gray's BAS and BIS [An exploratory question revolved around whether temperament factors, compared to character factors, will contribute more to predicting the stability of outcomes , 29–32.  and BIS , respectSeveral limitations of this study should be acknowledged. First, individuals who chose not to participate by not returning the survey packet may represent a different slice of the population than those represented in this particular sample, suggesting the possibility of representational bias. However, given that the prevalence of the Tae-Eum type is approximately 50% and that of the So-Yang and So-Eum types are approximately 25% each , 26, theSasang typology. Although only those participants who were rated by three experienced specialists in Sasang typology as a particular Sasang type at a high confidence level based on response to medication, future studies should utilize a diverse source of Sasang type classification to enhance reliability such as the combination scores from the research- and clinical-oriented methods.Second, we did not incorporate multi-method means of classifying post-hoc analyses, a significant difference was not found with the Tae-Eum type. However, a unique difference was observed between the Tae-Eum versus the So-Yang and So-Eum types when physical characteristics were examined [Third, although significant differences between the So-Yang and So-Eum types were found in the examined , 3. It iDongyisoosebowon [Yellow Emperor's Classic of Internal Medicine [Lastly, the nature of the So-Yang type is characterized by the feature of anger, a component of negative affect , and theosebowon  and YellMedicine . At firsMedicine , 6, 31. Sasang types and indicates a need for future studies that examine more closely at the neuroscience of the BAS/BIS system as well as the positive and negative affect related to Sasang types. Second, utilization of our results may lead to more enhanced clinical safety and efficacy as part of personalized medicine in medication use and may provide an important clinical guideline with individual's temperament in the use of medical herbs.In summary, two points should be emphasized. First, our analysis revealed stable biopsychological differences between the So-Yang and So-Eum This work was supported by the Korea Science and Engineering Foundation (KOSEF) grant funded by the Korea government (MEST) (No. M10643020004-08N4302-00400).


Our primary objective was to establish a cutoff value for the soluble fms-like tyrosine kinase 1(sFlt-1)/placental growth factor (PlGF) ratio measured using the Elecsys assay to predict late-onset preeclampsia in low-risk pregnancies. Our secondary objective was to evaluate the ability of combination models using Elecsys data, second trimester uterine artery (UtA) Doppler ultrasonography measurements, and the serum fetoplacental protein levels used for Down’s syndrome screening, to predict preeclampsia.This prospective cohort study included 262 pregnant women with a low risk of preeclampsia. Plasma levels of pregnancy-associated plasma protein-A (PAPP-A) and serum levels of alpha-fetoprotein, unconjugated estriol, human chorionic gonadotropin, and inhibin-A were measured, and sFlt-1/PlGF ratios were calculated. All women underwent UtA Doppler ultrasonography at 20 to 24 weeks of gestation.Eight of the 262 women (3.0%) developed late-onset preeclampsia. Receiver operating characteristic curve analysis showed that the third trimester sFlt-1/PlGF ratio yielded the best detection rate (DR) for preeclampsia at a fixed false-positive rate (FPR) of 10%, followed by the second trimester sFlt-1/PlGF ratio, sFlt-1 level, and PlGF level. Binary logistic regression analysis was used to determine the five best combination models for early detection of late-onset preeclampsia. The combination of the PAPP-A level and the second trimester sFlt-1/PlGF ratio yielded a DR of 87.5% at a fixed FPR of 5%, the combination of second and third trimester sFlt-1/PlGF ratios yielded a DR of 87.5% at a fixed FPR of 10%, the combination of body mass index and the second trimester sFlt-1 level yielded a DR of 87.5% at a fixed FPR of 10%, the combination of the PAPP-A and inhibin-A levels yielded a DR of 50% at a fixed FPR of 10%, and the combination of the PAPP-A level and the third trimester sFlt-1/PlGF ratio yielded a DR of 62.5% at a fixed FPR of 10%.The combination of the PAPP-A level and the second trimester sFlt-1/PlGF ratio, and the combination of the second trimester sFlt-1 level with body mass index, were better predictors of late-onset preeclampsia than any individual marker. Preeclampsia is characterized by hypertension and significant proteinuria during pregnancy. This multisystem disorder occurs in approximately 3% of pregnancies, and canRecent evidence indicates that there are numerous phenotypes of preeclampsia, indicating that a number of pathophysiologic mechanisms related to the mother and fetus may contribute to the timing of disease onset. PreeclaPreeclampsia is one of the leading causes of maternal mortality worldwide, and in developed countries it increases perinatal mortality five-fold. Chronicet al.[It has been suggested that placental soluble fms-like tyrosine kinase 1 (sFlt-1) is a causative factor in preeclampsia. sFlt-1 acts as a potent vascular endothelial growth factor (VEGF) and placental growth factor (PlGF) antagonist by binding to these molecules and thereby reducing the free circulating levels of VEGF and PlGF. Decreased levels of circulating VEGF and PlGF appear to result in reversal of physiological vasodilation, leading to hypertension. Severalet al. reportedet al.[In high-risk women, persistently increased uterine artery (UtA) resistance during the first half of pregnancy is associated with a high risk of early-onset preeclampsia. A combiet al. reportedThe integrated test for fetal Down’s syndrome uses a combination of placental biomarkers. Among these markers, the levels of pregnancy-associated plasma protein (PAPP-A) and inhibin-A are positively associated with subsequent preeclampsia-16. Howe2. All the cases of preeclampsia included in the study were diagnosed with severe preeclampsia after 35 weeks of gestation (late-onset preeclampsia), and the time of diagnosis was almost the same as the time of delivery.This prospective study analyzed the risk of preeclampsia according to the results of blood sample analyses in pregnant women at low risk of preeclampsia. The study included women who received regular antenatal care at the prenatal care unit of Cha Hospital in Seoul, Korea between April 2011 and December 2011. All patients were recruited before 10 weeks of gestation, based on measurement of the fetal crown-rump length. All subjects underwent the integrated test for fetal Down’s syndrome, UtA Doppler ultrasonography at 20 to 24 weeks of gestation, and calculation of the sFlt-1/PlGF ratio at 24 to 27 and 34 to 37 weeks of gestation. Women were excluded if they were aged ≥ 40 years or had a multifetal pregnancy, chronic hypertension, prior history of preeclampsia, pregestational diabetes mellitus, gestational diabetes mellitus, delivery before 35 weeks of gestation, early-onset preeclampsia (before 35 weeks of gestation), or body mass index (BMI) ≥ 25 kg/mPreeclampsia was defined according to the National High Blood Pressure Education Program Working Group on High Blood Pressure in Pregnancy criteria. Hypertension was defined as repeated systolic blood pressure measurements of ≥ 140 mmHg (Korotkoff phase 1) and diastolic blood pressure measurements of ≥ 90 mmHg (Korotkoff phase 5). Proteinuria was defined as ≥ 300 mg of protein in a 24-hour urine collection sample, or repeated ≥ 1+ proteinuria on dipstick urinalysis. PreeclaAll women provided written informed consent before the collection of blood samples. The collection and use of samples for the purposes of this study were approved by the Institutional Review Board of CHA Gangnam Medical Center, CHA University.+0 to 13+6 and 15+0 to 20+6 weeks of gestation for measurement of the plasma PAPP-A level and the serum levels of the quadruple test markers: alpha-fetoprotein (MSAFP), unconjugated estriol, human chorionic gonadotropin (hCG), and inhibin-A. Markers were measured using a UniCel DxI 800 analyzer  and the values were transformed to multiples of the median (MoM) after adjusting for gestational age and maternal BMI.All women underwent the integrated test for fetal Down’s syndrome. Maternal serum samples were obtained at 11+0 to 27+6 and 34+0 to 37+6 weeks of gestation. After clotting, the samples were centrifuged and plasma was stored at -80°C. The sFlt-1 and PlGF levels of each sample were measured simultaneously using the fully automated Roche Diagnostics Elecsys assay , and the sFlt-1/PlGF ratio was calculated.To measure the plasma levels of sFlt-1 and PlGF, venous blood was collected in silicon-coated glass tubes at 24UtA Doppler transabdominal ultrasonography with color flow mapping was performed at 20 to 24 weeks of gestation. The bilateral UtA Doppler impedance indices were recorded according to the Fetal Medicine Foundation guidelines, includiData are expressed as the median (range) and were analyzed using non-parametric methods.a posteriori risk of preeclampsia for each patient using the panel of available markers expressed in terms of MoM and parity.Weighted log10-linear regression was used to calculate the median values for the levels of sFlt-1, PlGF, PAPP-A, alpha-fetoprotein (MSAFP), β-hCG, unconjugated estriol, and inhibin-A, and the highest uterine artery pulsatility index, mean uterine artery pulsatility index, highest uterine artery resistance index, mean uterine artery resistance index, and nuchal translucency thickness, as a function of fetal crown-rump length and maternal weight for the 254 subjects without preeclampsia. The results for all subjects were then expressed as MoM values. Repeated analysis of variables was used to calculate the effects of gestational age on variables. Receiver operating characteristic (ROC) curve analysis was used to determine the detection rate (DR) of each marker for subsequent late-onset preeclampsia at a fixed false-positive rate (FPR). Logistic regression analysis was used to calculate the 1χ1 + β2χ2 + … βnχn where α is the constant of the model , β is the coefficient associated with the risk factor, χ is the risk factor, and y is the odds of preeclampsia. Therefore, odds = exp(y) and risk = odds/(1 + odds).The logistic regression equation used was ln(y) = α + βAnalyses were performed using the Statistical Package for the Social Sciences version 19.0  and Power Analysis and Sample Size version 11 .th percentile) were significantly more frequent in patients with preeclampsia than in patients without preeclampsia (p = 0.006). The MoM values of all the biochemical markers except for the MSAFP level, and of nuchal translucency thickness, were significantly different between patients with and without preeclampsia  and 5% . The third trimester sFlt-1/PlGF ratio yielded a DR of 87.5% at a fixed FPR of 10%  and a DR of 50% at a fixed FPR of 5% . The Elecsys instructions recommend using an sFlt-1/PlGF ratio of > 85  for diagnosing preeclampsia. The results of this study show that the sFlt-1/PlGF ratio is a useful predictor of late-onset preeclampsia. Ohkuchi et al.[et al.[The Elecsys system is an immunoassay system that measures plasma sFlt-1 and PlGF levels. Although it was developed for diagnostic testing of patients with preeclampsia, a carefully established cutoff value could potentially enable detection of subclinical preeclampsia. A recent study demonstrated patients with preeclampsia or the syndrome of hemolysis, elevated liver enzymes, and low platelet count with a high sFlt-1/PlGF ratio were at significantly increased risk of imminent delivery, and the authors proposed that the sFlt-1/PlGF ratio be used as a prognostic marker. In our hi et al. reportedl.[et al. reportedl.[et al..th percentile for gestational age[In this study, small-for-gestational-age infants were usually associated with preeclampsia. In patients without preeclampsia, the median sFlt-1/PlGF ratio at 34 to 37 weeks of gestation was low but had a very wide range . Four patients had an sFlt-1/PlGF ratio of > 85. Among these patients, the mean UtA pulsatility index was above the 95In this study, the combination of the second and third trimester sFlt-1/PlGF ratios and the combination of the PAPP-A level and the second trimester sFlt-1/PlGF ratio yielded the best DRs. The sFlt-1/PlGF ratio measured shortly before delivery at or beyond 34 weeks of gestation has little value as a screening test, because delivery is an effective treatment for late-onset preeclampsia. However, if the second trimester sFlt-1/PlGF ratio is equivocal and the patient does not have preeclampsia at 34 weeks of gestation, serial measurements may help clinicians to detect and manage emerging late-onset preeclampsia. The combination of the PAPP-A level and the second trimester sFlt-1/PlGF ratio is therefore the best marker for early detection of late-onset preeclampsia.et al.[et al.[Akolekar et al. developel.[et al. reportedet al.[A weak point of our study is the different risk estimation results obtained when different combinations of markers were used in the same subject. This is probably due to the low number of patients with preeclampsia, and the fact that preeclampsia results from various pathophysiologic mechanisms that may alter the markers in different ways. However, three of the eight cases were detected by all the models used, and all the cases were detected by at least two of the models. The strong points of the study include its prospective design and the evaluation of several markers for predicting preeclampsia. The combinations used in this study appear to have higher predictive accuracy than the combination of first-trimester maternal risk factors and mean arterial pressure used in the large prospective study by Poon et al., which ret al., and we The Elecsys sFlt-1/PlGF ratio allows identification of low-risk pregnancies at high risk of developing preeclampsia. A cutoff value of 6.05 in the second trimester and 28.15 in the third trimester had the best ability to predict preeclampsia at a fixed FPR of 10%. The PAPP-A level and BMI can be used in combination with the sFlt-1/PlGF ratio to increase the rate of detection of preeclampsia. Further studies are required to assess the usefulness of our combined screening test in low-risk populations.All authors declare that they have no competing interests.DHC and KJL conceived of the study. HJP, DHC, KJL and SHK participated in the study design. AF and MZ performed the statistical analyses. HJP, AF and MZ interpreted the data. HJP drafted and revised the manuscript. HJP, DHC, KJL, SHK, SSS, JYK and YKC made substantial contributions to the acquisition of data. DHC, KJL, YWJ and AF critically reviewed the manuscript. All authors read and approved the final manuscript.The pre-publication history for this paper can be accessed here:http://www.biomedcentral.com/1471-2393/14/35/prepub


C5L2, a G protein-coupled receptor (GPCR), has been demonstrated to be a ligand for acylation-stimulating protein (ASP). The aim of the present study is to evaluate the association of a novel variation (901A > G) of C5L2 gene with coronary artery disease (CAD).We identified a novel single nucleotide polymorphism (SNP), (901G > A), in exon 2 using a polymerase chain reaction direct-sequencing method. This nucleotide change causes the amino-acid order from Arginine to glutaminate at codon 300. We analyzed the relationship between this SNP and CAD in two independent case–control studies: one was in a Han population (492 CAD patients and 577 control subjects) and the other was in a Uygur population (319 CAD patients and 554 control subjects).The frequency of AG genotype in CAD subjects was less than that in the control subjects not only in Han  but also in Uygur population . After adjustment for known CAD risk factors such as hypertension, diabetes, smoking, age and gender, the difference remained significant.The 901G > A polymorphism of C5L2 may be a genetic maker of CAD in the Han and Uygur population in western China. Coronary artery disease (CAD) is a complex multifactorial disorder involved multiple environmental risks and genetic factors ,2 which In humans, Acylation Stimulating Protein (ASP) levels are increased in obesity, type 2 diabetes (T2DM), and cardiovascular disease. ASP is a human plasma protein that stimulates both triacylglycerol synthesis and glucose transport via its receptor C5L2. C5L2 is a potential ligand for both C5a (a powerful inflammatory factor) and ASP. It added one addition association between the adipose and the immune system. Other study have demonstrated that ASP binds to C5L2, initiating a cascade of events that includes phosphorylation, β-arrestin translocation, and receptor internalization. Activation of C5L2 initiates protein kinase C activation and translocation and glucose transporter translocation -16. ThisIn a previous study , we idenTable The genotype distribution of 901A > G did not show a significant difference from the Hardy–Weinberg equilibrium values in both ethnicities (Both P > 0.05 in CAD group and control group). The frequency of the heterozygote carriers of the 901 GA genotype of C5L2 was significantly lower in CAD patients than that in control subjects not only in Han  but also in Uygur  Table .In the present study, we identified a novel SNP (901G > A) and found that the GA genotype is associated with decreased risk for CAD in a Han and in a Uygur population of Xinjiang, the western China.There are increasing evidences of close interactions between immune systems and adipose biology, which is a concept now well recognized within metabolic research in the areas of obesity, insulin resistance, diabetes and cardiovascular disease, as highlighted by numerous review articles -20. C5L2P <0.05). Hence, we also examined if the relationship between the C5L2 genetic variant and CAD is modified by the concentration of HDL-C and diabetes. We found the relation between 901G > A variant and CAD was not modified by other factors including diabetes.In the previous study, Michel et al.  identifiThere were several limitations in the present study. Firstly, the present study was limited by the relatively small sample size. This may have led to weak statistical significance and wide CIs when estimating ORs. Secondly, we did not examine the expression of C5L2 between CAD and control group. Finally, we did not analyze the difference between each genotype in 901G > A polymorphism.In conclusion, CAD was associated with the GA genotype of 901G > A in the human C5L2 gene. This result may broaden the knowledge of genetic variants and disease-association studies. Undertaking genome-wide association studies in different populations certainly merits investigation.Two case–control studies (Han and Uygur) were studied independently. Subjects diagnosed with CAD at the First Affiliated Hospital of Xinjiang Medical University from January 2006 to December 2009 were recruited. In this hospital approximately 2500 patients undergo coronary angiography every year and we selected 492 Han patients and 319 Uygur patients for this study. CAD diagnosed by angiography, which was defined as the presence of at least one significant coronary artery stenosis of ≥50% luminal diameter on coronary angiography. To ensure matching for age and gender, we selected 554 Han and 577 Uygur healthy subjects from the Cardiovascular Risk Survey (CRS) study which was described previously -25. BrieHypertension was defined as having a systolic blood pressure above140 mmHg or/and diastolic blood pressure above 90 mmHg or any anti-hypertensive agent used.2) in units of kg/m2. All participants underwent a standardized physical examination performed by experienced research staff. Standing body height (cm), weight (kg) and waist circumference  were noted previously [Dyslipidemia was diagnosed according the current guidelines from the National Cholesterol Education Program (NCEP) Adult Treatment Panel (ATP) III, that any abnormal status of TG, HDL-C and LDL-C , Hypercholesterolaemia was defined as a documented total cholesterol value ≥200 mg/dl (≥5.2 mmol/L) , or curreviously -25. Infohttp://www.genomics.cn), sequencing primers were designed using Primer Premier 5.0 software. The sense primer was 5’ TGCTCACTG TGGCGGCCCCGA3’ and the antisense primer was 5’CCTTTTTAGGCACTAGAG ATA3’.Genomic DNA extraction from peripheral blood samples and complete sequencing of the C5L2 region that included a portion of the upstream region, 1 intron, and the exons have been described previously . SequencThe detailed of genotyping of novel SNP have been previously described. Briefly, DNA sequencing of complete C5L2 region using a polymerase chain reaction direct-sequencing method, we identified a heterozygous variant 901G > A) in 48 subjects with CAD ,Data are expressed as the mean ± standard deviation (SD). The significance of differences was evaluated using the t-test for continuous variables and the χSNP: Single nucleotide polymorphisms; CAD: Coronary artery disease; ASP: Acylation-stimulating protein; TG: Triglycerides; TC: Total cholesterol; HDL-C: High-density lipoprotein; LDL-C: Low-density lipoprotein.The authors declare that they have no competing interests.YYZ and XX carried out the molecular genetic studies and drafted the manuscript.YNY, ZYF and XML carried out the genotyping. XM and BDC participated in the design of the study and performed the statistical analysis. YTM, FL and YYZ conceived of the study and participated in its design and coordination and helped to draft the manuscript. All authors read and approved the final manuscript.


Correct control selection is crucial to the internal validity of case-control studies. Little information exists on differences between population and hospital controls in case-control studies on cancers in Chinese hospital setting.We conducted three parallel case-control studies on leukemia, breast and colorectal cancers in China between 2009 and 2010, using population and hospital controls to separately match 540 incident cases by age, gender and residency at a 1:1 ratio. Demographic and lifestyle factors were measured using a validated questionnaire in face-to-face interview. Odds ratios (ORs) and 95% confidence intervals (CIs) were obtained using conditional logistic regression analyses.The two control groups had closely similar exposure distributions of 15 out of 16 factors, with the only exception being that hospital controls were less likely to have a BMI ≥ 25 . For exposure of green tea drinking, the adjusted ORs (95% CIs) comparing green tealeaves intake ≥ 1000 grams annually with non-drinkers were 0.51  and 0.21  for three cancers combined, 0.06  and 0.07  for breast cancer, 0.52  and 0.45  for colorectal cancer, 0.65  and 0.57  for leukemia using hospital and population controls respectively.The study found that hospital controls were comparable with population controls for most demographic characteristics and lifestyle factors measured, but there was a slight difference between the two control groups. Hospital outpatients provide a satisfactory control group in hospital-based case-control study in the Chinese hospital setting. Correct control selection is crucial to the internal validity of case-control studies ,2. The fWhen we applied successfully to Australia's National Health and Medical Research Council to perform case-control studies in China on the effects of green tea on the incidence rates of colorectal cancer, breast cancer and adult leukemia, it became a condition of funding that we recruit both hospital and population controls for around one fifth of the case series to determine if there was any difference of practical importance.A handful of studies have compared different control groups in western countries where non-emergency access to hospital care generally depends on referral from medical practitioners in non-institutional settings -14. WhenIt was important to understand whether exposures measured in the study were in agreement when ascertained from population and hospital control groups, especially because our previous case-control studies of green tea and cancer in China had used hospital controls. This study aimed, therefore, to compare key exposure distributions between hospital controls and alternative population controls to determine if there was any difference of practical importance, and to examine if inferences drawn from green tea effect estimates for different cancer case groups using hospital controls would be different from those using population controls in the Chinese hospital setting.The study, as a validation component of three large case-control studies of malignancies, was conducted in Shenyang, the capital city of Liaoning Province, Northeast China. In August 2009 to July 2010, 540 incident cases with a primary diagnosis of leukemia, or breast cancer, or colorectal cancer were identified from histopathology and haematology records at the First Hospital of China Medical University, a public teaching hospital with 2,249 beds, around 32,000 inpatients annually and 3,000 outpatients daily. The eligible cases were permanent residents of urban Shenyang aged 18 to 85 years. During the study period, 540 population controls and 540 hospital controls were selected from Shenyang residents and from outpatients at the same hospital to separately match cases in a 1:1 ratio. Most of controls were interviewed within three months after cases were interviewed.The methods of recruiting population controls were similar to those used in case-control studies in Shanghai, China ,17. PopuHospital controls were drawn from the population of patients in the hospital . A systeSubjects were briefed regarding confidentiality and anonymity issues and the general aims of the study to investigate lifestyle factors. An appointment for an interview was made after obtaining the respondent's consent via an initial contact. A face-to-face interview was then conducted by the first author, using a structured questionnaire and usually took 30-40 minutes. The validated questionnaire, available from the authors upon request, was used to collect the information on: (i) demographic and lifestyle characteristics, e.g., area of residence, education, smoking, alcohol and tea consumption and physical activity; (ii) dietary intake assessed by a food frequency questionnaire (FFQ); and (iii) factors relevant to hormonal status and family history of cancer. The questionnaire was adapted from that used in our previous studies on cancers . This in2). Daily energy intake and alcohol consumption were assessed using the FFQ. The frequencies of 100 food items, including beer, wine, and liquor intake, were assigned into nine categories: never or hardly ever; once a month; 2-3 times a month; once a week; 2-3 times a week; 4-6 times a week; once a day; twice a day; and ≥ 3 times a day. Food and alcohol consumption was based on habitual diet and a 'reference' recall period was set as one year prior to diagnosis for cases or interview for controls. If there was any recent change in habits, only information on the habits before the change was used in data analysis. The frequency and quantity variables derived from the FFQ were converted into daily food consumption, adjusted for the edible portions of foods, cooking methods, seasonal factors, and market availability [All data were checked at the end of each interview for completeness and were coded and analysed using SPSS version 18.0. Participants' self-reported current height in meters and weight in kilograms were used to calculate body mass index (BMI) , 95% confidence intervals (95% CI) and p-values for trend estimated from conditional logistic regression adjusted for education, income, household size, BMI, smoking, alcohol, tea consumption, energy intake , and physical activity. The ORs were for the odds of being a hospital rather than population control. Each quantitative or ordinal quantitative measure was subjected to a linear trend test.All cancer case groups combined, breast cancer, colorectal cancer, and leukemia only subgroups were analysed separately using the two types of matched control groups with regard to green tea intake using conditional logistic regression, adjusted for education, BMI 5 years ago, smoking, passive smoking, alcohol consumption, energy intake , physical activity, and cancer in first degree relative. For breast cancer only subgroup, the regressions analyses also adjusted for menopausal status, oral contraceptive use, and number of children breastfed.Data were collected on a total of 1080 controls. Interviews were completed for 540 (89.7%) of the 602 eligible population controls who were approached to participate. The only reason for non-participation was refusal to provide a blood sample, which was an essential part of the study. Of 563 eligible hospital controls who were approached to participate, interviews were completed also for 540 (95.9%). For the 540 recruited cancer cases, the response fraction was 98.5%.Comparisons of distributions of demographic characteristics and lifestyle factors between hospital and population controls are shown in Table Table Table This validation study, as a component of three large case-control studies of malignancies, used separate hospital outpatient and population control groups to assess differences in the distributions of demographic characteristics and lifestyle factors between the two control groups. Furthermore, the study evaluated if different conclusions were reached when comparing cases with matched hospital controls or population controls in the effect of green tea intake. The study found that the distributions of study exposures in hospital outpatient controls were similar to those in population controls. In addition, we obtained similar results in assessing the effect of green tea drinking on three cancers together and separated, using hospital outpatient controls and population controls respectively. Therefore, our results suggest that in the context of a case-control study conducted at a Chinese hospital using urban cases, regardless of whether controls were selected from hospital outpatient attendees without malignancy or drawn from population household registries covering populations in the catchment area of the participating hospital, the two control groups appeared to have similar exposure distributions. Our results identified one exception to this general conclusion. It is possible that population controls may tend to report higher levels of being overweight than hospital outpatient controls.The findings of this investigation were consistent with a smaller pilot study conducted in 1999-2000 by our research team -10, as wA key exposure in our work was green tea drinking measured in three parallel case-control studies. For three cancers together, breast cancer, colorectal cancer, and leukemia, the inversed associations were similar in their direction and size regardless of which control series was employed to represent the underlying exposure to higher green tea consumption. The results, using either type of control series, were consistent with our previous finding that increasing the quantity of green tea consumption reduces the risk of breast cancer in Chinese women , as wellWhilst hospital outpatient and population controls selected in this study may function in a similar manner for a hospital case-control design in China, this does not entirely resolve the underlying theoretical debate as to which of the two types of control group is the more defensible. For BMI, for example, where our study did find evidence of some practical and statistical differences, one is left with the question of which control exposure distribution is more representative of that in the population at risk of becoming a case. The result may have simply been due to chance, although the possibility that population controls were more likely to be overweight cannot be ignored. On the other hand, the lower response fraction of population controls  may have provided the circumstances where normal weight individuals in the general population were less inclined to participate in a research study on health and lifestyle.In China, public hospitals provide treatment services for acute, severe, and critical outpatients and inpatients, and they fulfill education, research, prevention, and rehabilitation objectives by providing special medical services. All public hospitals have preventive health care branches, which are responsible for reporting infectious diseases, health checks, health counseling, community prevention services, health education, disease screening, family planning and birthing guidance, and care of staff . PatientAs there is almost never one ideal control group, some researchers believe that population registers provide the most valid way of sampling controls in a hospital case-control study ,11-14, bWith respect to the demographic characteristics and lifestyle factors included in the present study, our results suggest that hospital outpatient controls performed little different from population controls for most exposures. For the key exposure, the effect estimates for different cancer case groups using hospital outpatient controls were similar to those using population controls. Therefore, even though some points of concern exist, hospital outpatients provide a satisfactory control group in hospital-based case-control study in the Chinese hospital setting.MET-hour: metabolic equivalent task hour; BMI: Body mass index; OR: odds ratio; 95% CI: 95 percent confidence interval.The authors declare that they have no competing interests.LL collected the data, conducted data analysis, interpretation, and drafted the manuscript. MZ designed the study, directed all aspects of its implementation, including quality assurance and control, assisted data analysis, and reviewed drafts of the article. DH designed the study, supervised all aspects of its implementation, and reviewed drafts of the article. All authors have read and approved the final manuscript.The pre-publication history for this paper can be accessed here:http://www.biomedcentral.com/1471-2288/11/167/prepub