The relationship between surfactant-associated protein D polymorphisms and chronic obstructive pulmonary disease risk remains controversial. This article is the first to systematically evaluate this relationship. A comprehensive worldwide search was conducted for relevant literature on surfactant-associated protein D gene mutations and chronic obstructive pulmonary disease risk prediction. Study quality was evaluated using the Newcastle-Ottawa scale. After four genetic models  were identified, odds ratios (ORs) and the corresponding 95% confidence intervals (CIs) were applied in this meta-analysis. The meta-analysis included 659 individuals in the case group and 597 in the control group. In the Asian population, none of the four genetic models revealed any significant association between rs2243639 genotype and the risk of chronic obstructive pulmonary disease. In Caucasians, however, the recessive model exhibited significant risk associated with rs2243639. Furthermore, there was a significant association between rs721917 genotype and the risk of chronic obstructive pulmonary disease in the Asian population. In contrast, none of the four gene models revealed any significant risk associated with this gene in the Caucasian population. This meta-analysis suggests that rs2243639 is not related to the risk of chronic obstructive pulmonary disease in the Asian population but is related to this risk in the Caucasian population. Regarding rs721917, the T allele may increase the risk of chronic obstructive pulmonary disease in the Asian population. Chronic obstructive pulmonary disease (COPD) is a preventable, treatable disease characterized by persistent airflow limitation accompanied by gradual deterioration of lung function and a series of abnormalities in mental and physical functions The pathogenesis of COPD is still not fully understood. It is generally believed to be related to inflammation, protease-antitrypsin imbalance, and oxidative stress stimulation. It is widely believed that COPD is caused by both environmental and genetic factors. In recent years, with the development of genome-wide association study (GWAS) technology, increasing numbers of COPD-related susceptibility genes have been discovered, such as tumor necrosis factor-α (TNF- α), transforming growth factor-β1 (TGF-β1), A disintegrin and metalloproteinase 33 (ADAM33), superoxide dismutase (SOD), alveolar surface-associated protein D (SP-D) and other related susceptibility genes Alveolar surfactant-associated protein (SP) is an active substance synthesized and secreted by alveolar type II epithelial cells. It is composed of phospholipids and a small amount of protein, and it usually covers the alveolar surface to maintain alveolar surface tension and promote the smooth progress of pulmonary ventilation. It also has immunomodulatory and anti-inflammatory effects Increasing studies have been performed to assess polymorphisms of the SP-D gene, but some controversies remain. The data on SP-D single nucleotide polymorphisms (SNPs) has primarily focused on rs2243639 and rs721917. Therefore, this meta-analysis was performed to explore the relationship between the abovementioned SNPs and the risk of developing COPD.A comprehensive search was conducted for relevant literature published by scholars worldwide on SP-D gene mutations and COPD risk prediction. The databases searched were the Wanfang Data Knowledge Service Platform and the VIP Chinese Science and Technology Periodical Database (VIP), the China National Knowledge Infrastructure (CNKI), the China Dissertation Database, PubMed, Embase, the Cochrane Library, and Web of Science. The retrieval time was set from January 1, 1997, to September 30, 2018. The search terms were “surfactant-related protein D gene” and “chronic obstructive pulmonary disease”. The results were limited to articles in English and Chinese. The literature screening process is shown in The inclusion criteria were as follows: 1) The article was related to polymorphisms of the SP-D gene and the risk of COPD, 2) the study was a case-control, cohort, or group design study, 3) the inclusion and exclusion criteria of the case and control groups in the study were clear, and the experimental goals included were in line with the aim of this meta-analysis, 4) there were complete experimental data and results, 5) The case group and the control group involved human subjects, and 6) the article was written in English or Chinese.The exclusion criteria were as follows: 1) duplicate report, 2) defects and poor-quality study design, 3) incomplete data and unclear outcome effect, 4) flawed statistics and the inability to extract relevant data, 5) animal experiments, and 6) non-Chinese- and English-language articles.The two researchers independently screened the literature to exclude the literature that did not meet the inclusion criteria. Differences were resolved through group discussion. Data were extracted independently according to the predesigned form, and the extracted data were cross-checked. The following information was extracted from each study: name of the first author, year of publication, race, definition and source of the control and case groups, smoking status in cases and controls, and the number of genotypes and individual base pairs.The quality of the included literature was evaluated by two independent researchers in strict accordance with the Newcastle-Ottawa Scale (NOS) vs B), 2. The additive model (AA vs BB), 3. The recessive model (AA vs AB+BB), and 4. The dominant model (AA+AB vs BB) p>0.05, 2I<50%), the M-H fixed effect model was used to calculate the odds ratio (OR) and its 95% confidence interval (CI). If the heterogeneity was significant , the OR and its 95% CI were randomly calculated using the M-H heterogeneity random effects model. At the same time, subgroup analyses were performed using different ethnic classifications. All included articles were analyzed for bias using the Egger method. If p<0.05, publication bias was considered. The risk of bias is shown in All data included in the literature were analyzed using Stata MP13.0 (64-bit). At the same time, to reduce the probability of type I errors In total, 420 articles were initially collected, and 380 articles that did not meet the inclusion criteria were then excluded. Thirty articles that had defects in experimental design, case-control criteria, and other aspects were excluded based on the information in the abstract. After reading the full texts of the remaining articles, 4 additional articles were excluded. In total, 6 articles 2=55.6%) and recessive model . When using the fixed effect model, there was low heterogeneity in the additive model  and the dominant model . In the subgroup analysis in the Asian population, the allelic model , additive model , recessive model , and dominant model  revealed no association. However, for Caucasians, the recessive model was significantly different    Table 52=55.6% a2=0%), additive model , recessive model , and dominant model  had low heterogeneity. In the subgroup analysis, in the Asian population, there was low heterogeneity in the allele model , additive model , recessive model , and dominant model . There were no significant differences in the risk of COPD in the Caucasian population in the four gene models  in the polymorphic locus of rs2243639 in the exon 5 region of the SP-D gene. For the Asian population, the rs2243639 polymorphism was found in both patients with COPD and healthy individuals. There was no significant difference in the risk of COPD between those with the polymorphism and those without. Surprisingly, subgroup analysis revealed that SPD polymorphisms, particularly the G allele, increased the risk of susceptibility to COPD in Caucasians. Nevertheless, only one genetic model was significantly different, the sample size of the Caucasian population was small, and only one group was included in the meta-analysis. Therefore, caution should be taken in the interpretation of the research results, and a larger sample size and well-designed investigation will be necessary to confirm the conclusion of this study.For rs721917, the rs721917 polymorphism and the risk of COPD were significantly associated in the Asian population but not the Caucasian population. In the SP-D exon 1 region, there are three rs721917 genotypes . The included studies and this meta-analysis showed that compared to the C allele, the T allele may increase the risk of COPD in the Asian population but not in the Caucasian population. Foreman et al. This meta-analysis had some deficiencies. First, the number of included studies was relatively small, and the included studies were all written in Chinese or English. Useful studies in other languages may have been missed. At the same time, papers from academic conferences and other documents were not included. Second, the analysis of publication bias revealed bias in the recessive model of the rs2243639 polymorphism, and the HWE test showed that some of the included samples did not adhere to the Hardy–Weinberg principle. Third, data from Caucasian populations were scarce. At the same time, the proportion of Chinese individuals among those from Asian populations was relatively high, which had an impact on the conclusions. Fourth, in some of the included studies, there were statistically significant differences in smoking status between the case group and the control group, which also affected the results.According to the results of the current meta-analysis, the rs2243639 polymorphism was associated with the risk of COPD in Caucasian populations but not in Asian populations. Among Asians, compared with the C allele for rs721917, the T allele may increase the risk of COPD. Due to the limitations of the quality and quantity of the articles included in the present meta-analysis, the conclusions obtained need to be confirmed by more uniform case–control or cohort studies.We express our thanks for the English editing services of American Journal Experts.


PPAR) gene Pro12Ala polymorphisms and risk of hypertension. However, the number of available studies was extremely limited. We updated this evidence and gave more significant results. We performed comprehensive computer-based searches in the PubMed, Web of Science, Embase, Google Scholar, the Cochrane library, Wanfang database, China National Knowledge Infrastructure, and China Biological Medicine Database. All studies that reported the association between the PPARγ2Pro12Ala polymorphisms and hypertension were identified. Twenty-one studies were finally included in the present study. In the domain model, the PPARγ1Pro12Ala polymorphism was not associated with hypertension (odds ratio (OR) = 0.85, 95% confidence interval (CI): 0.71–1.03, P=0.108). The significant relationship was found in the recessive model , in the additive model , and in the allele genetic model . Subgroup analysis indicated that the PPARγ1Pro12Ala polymorphism from the all gene models was also not related to the risk of hypertension in Caucasians. In Asians, however, the results  suggested a significant relationship between PPARγ1Pro12Ala and hypertension in the domain model , in the recessive model , in the additive model , and in the allele model . The PPARγ1Pro12Ala polymorphism could affect the risk of primary hypertension amongst Asians. The A allele gene was a protective genotype for primary hypertension. The PPARγ1Pro12Ala polymorphism was not associated with hypertension amongst Caucasians.Previous studies investigate the relationship between peroxisome proliferator-activated receptor γ-2 ( Cardiovascular disease is the leading cause of death for adults in developed or developing countries, including China . HypertePeroxisome proliferator-activated receptor-γ (PPARγ) belongs to member of the steroid hormone receptor superfamily. Human PPARγ gene is located in the chromosome of 3p25 with 479 amino acid resides . Recent This meta-analysis was in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) and Cochrane Handbook for Systematic Reviews.We performed comprehensive computer-based searches in the PubMed, Web of Science, Embase, Google Scholar, the Cochrane Library, Wanfang database, China National Knowledge Infrastructure, and China Biological Medicine Database from the inception to 28 December 2018. All studies that reported the association between the PPARγ2Pro12Ala polymorphisms and hypertension were identified. The following keywords were used for searching: peroxisome proliferator-activated receptor-γ, PPAR-γ, Pro12Ala, genotype, polymorphism, mutation, single nucleotide polymorphism  variant, hypertension. The search language was restricted to Chinese and English. We also reviewed the references lists of reviews and relevant studies for the potential studies as possible as we can.The included studies have to meet the following criteria: (i) study is from a case–control or cohort study design about relationship between PPAR-γ2Pro12Ala polymorphism and the risk of hypertension; (ii) the diagnostic of hypertension is clear: systolic blood pressure ≥ 140 mmHg or diastolic blood pressure ≥ 90 mmHg without antihypertension medications or antihypertension medications were used ; (iii) sTwo authors [M.Z. and Q.W.] independently extracted the data. Disagreement was resolved by consensus. If these two authors could not reach a consensus, the result was reviewed by a third author [L.F.]. The extracted data consisted of the follow items: the first author’s name, publication year, country, methods of genotype, sample size of cases and controls, the gene frequency  of case group and control group, Hardy–Weinberg equilibrium (HWE) test results, and scores of quality assessment.To determine the methodological quality of each study, we used the Newcastle–Ottawa Scale, which uses a ‘star’ rating system to judge the quality of observational studies . The NOSP<0.1) and the 2I test (greater than 50% as an evidence of significant inconsistency). Pooled effect sizes were determined using a fixed-effects model (the Mantel–Haenszel method) when heterogeneity was negligible (2I < 50%) or a random-effects model (the DerSimonian and Kacker method) when significant heterogeneity was present (2I ≥ 50%) [2 test in the controls. Subgroup analysis was also performed amongst different populations (Caucasian vs. Asian). We performed the sensitivity analysis by omitting one study each time. To study the relevance of such publication bias, funnel plots were constructed by plotting the trial results against their precision. Begg’s and Egger’s tests were also used to assess the publication bias [P-value less than 0.05 was considered statistically significant throughout the analyses.We assessed the association between PPAR gene Pro12Ala polymorphisms and risk of hypertension using the following gene model: dominant (AA/PA vs. PP), recessive (AA vs. PA/PP), additive (AA vs. PP), and allele gene model (A vs. P). The odds ratios (ORs) with 95% confidence intervals (CIs) were calculated to assess the relationship between gene models and risk of hypertension. Heterogeneity was assessed using the Chi-square test (significance level of 2 ≥ 50%) . HWE wasion bias . A P-valThis meta-analysis belonged to secondary analysis based on the studies published previously, the patients’ informed consent; and the ethical approval was not necessary.The flow of study selection was presented in The general characteristics of the studies included in the meta-analysis are shown in The score of each domain was presented in the Supplementary Material S1. The mean score of included studies was 7.04. The overall quality of studies was high. The main issues were that some studies selected a control population from a hospitalized one. Either cases and controls were not matched in the design and/or confounders were not adjusted for in the analysis. Besides, some studies did not report the non-response rate.P=0.000; 2I = 64.8%). We used the random-effect model to pool the data, which suggested that the PPARγ1Pro12Ala polymorphism was not associated with hypertension . To explore the population differences, we performed the subgroup analyses amongst different populations . We found that the PPARγ1Pro12Ala polymorphism was also not related to the risk of hypertension. In Asians, however, the results from random-effect model  indicated significant relationship between PPAR-γ1Pro12Ala and hypertension .To quantitatively assess the association between PPAR-γ1Pro12Ala and hypertension, we first pooled 21 studies in the domain model (AA/AP vs. PP). The results indicated there was significant heterogeneity .The sensitivity analysis result is presented in In the present study, our results based on larger sample sizes and more study number indicated that (i) PPAR-γ1Pro12Ala gene polymorphism was associated with the risk of hypertension. The AA genotype and A allele could decrease the risk of hypertension in the overall population compared with PP genotype and P allele, respectively. (ii) The population difference was source of heterogeneity within studies. Furthermore, (iii) the subgroup analysis suggested that the PPARγ1Pro12Ala gene polymorphism affects the risk of hypertension amongst Asians. However, no significant relationships were found amongst Caucasians. Our results provided more strong evidence support for the confirmation of relationship between PPARγ1Pro12Ala polymorphism and the risk of primary hypertension. Previous studies also assessed the relationship between common polymorphism (rs1801282) in the PPAR-γ2 gene and hypertension susceptibility ,33. HoweIn vitro, high-salt diet can make the SHR blood pressure significantly increased (185 + 6) mmHg vs. (128 ± 5) mmHg, and this process can be blocked by Rosiglitazone block (126 + 4 mmHg). Ang II synthetic process and glomerular mesangial cell proliferation was also inhibited, which indicated that the role in antihypertensive and protecting renal was associated with Ang II. Diep et al. [Our results found that the A allele appears to have a protective effect against hypertension. This result is similar to previous several studies. Lu et al.  found thp et al.  found thp et al. . During p et al. . The dirThe present study has several strengths. Compared with previous studies, our study consisted of a larger sample size (5503 cases and 7862 controls), which improved the statistical power and provided more accurate results. We also conducted subgroup analysis that were not reported in previous study. Besides, the present study followed the PRISMA and Cochrane Handbook for Systematic Reviews. Several study limitations should be addressed. First, the present pooled results were from unadjusted data, and some potential confounding factors may affect the results. We confirm that the population difference was one of the potential confounding factors. Second, we can see publication bias may exist though the Egger’s and Begg’s tests gave no significant results. Maybe it was related to search language because we only performed search in English and Chinese. Third, the study number and sample size in Caucasians was very limited. Studies with larger sample sizes are needed. Finally, future study should take the gene–environment effects into consideration.In conclusion, the PPAR-γ2 Pro12Ala polymorphism could affect the risk of primary hypertension amongst Asians. The A allele gene was a protective genotype in primary hypertension. The PPAR-γ1Pro12Ala polymorphism was not associated with hypertension amongst Caucasians. Study with more sample size is needed, especially for Caucasians. The future research should pay attention on the molecular mechanisms behind this.


Hypertension is dramatically increasing in Africa with evidence of increased severity and resistance to treatment. Although angiotensin converting enzyme gene polymorphism is associated with higher prevalence of hypertension, the evidence is inconclusive on its influence on the emerging pattern in Africa. This meta-analysis is conducted to pool the available evidence to inform future research and interventions.Articles published through May 2018 were systematically searched in PubMed, Scopus and EMBASE databases. Studies were assessed for inclusion by two independent researchers. Six models were used to assess the effect of angiotensin converting enzyme deletion-insertion gene polymorphism. Heterogeneity and publication bias were tested and sensitivity analysis was carried out. Odds ratio and 95% confidence intervals were measured for pooled effect. Both random effect and fixed effect models were used, whilst the frequency of DD, II and DI genotypes were computed and compared.Patients with D allele were 1.49 times more likely to develop essential hypertension compared with patients who carry the I allele . Similarly, patients who had homozygous co-dominance genotype DD  were at a 2.17 times higher risk of essential hypertension compared to the co-dominant genotype II , dominant model  , and recessive model . On subgroup analysis, participants from Sub-Saharan Africa were more genetically susceptible to hypertension compared to their North Africa counterparts. There was no publication bias found, but there was high to moderate heterogeneity.ACE I/D polymorphism is associated with essential hypertension in Africa in the allele contrast model, as well as the dominant, recessive and homozygous codominance model. On subgroup analysis, ACE I/D was associated with essential hypertension in patients from Sub-Saharan Africa but not in North Africa. A future large scale study, which includes different ethnic groups, is recommended. FurthGrowing hypertension prevalence and related complications are attributed to environmental and genetic factors – 9. The There are different genetic determinants involved in the pathogenesis of hypertension. The renin angiotensin aldosterone system (RAAS) is one of the most important pathways in the pathogenesis and management of hypertension. Angiotensin converting enzyme (ACE) is among the proteins involved in this pathway effecting salt retention, water balance and blood vessels; hence, it controls blood pressure. Drugs which inhibit this enzyme are effective in treatment of hypertension; however, these drugs are not first-line treatment in patients of African and African American origin . GeneticD allele is related to increased activity of ACE in serum [Angiotensin converting enzyme is encoded by the ACE gene, which is found in 17q23 and encoded by a 21 kb gene that consists of 28 exons and 25 introns. The insertion/deletion (I/D) polymorphism of ACE is characterized by the presence (insertion) or absence (deletion) of a 28 bp Alu repeat sequence in intron 16 producing three genotypes . Although the I/D polymorphism is located on a non-coding region  of the ACE gene, several investigators found that the in serum –21. Howein serum –21; wherin serum –25. TherThe study is conducted according to the HuGENet HuGE Review Handbook, Version 1.0  and the We searched PubMed, Embase and Scopus databases for articles published through May 2018 which investigated the association between ACE I/D gene polymorphism and the risk of essential hypertension. The search was limited to English language articles. The search terms used were as follows:  AND (“angiotensin-converting enzyme” OR ACEI) AND (insertion/deletion OR ACE I/D) AND “gene polymorphism” AND Africa . We alsoWe included studies which were case-control and used hypertension as an outcome of interest. Studies were excluded if they were case reports/editorials/reviews or multiple publications of the same dataset. Studies were excluded if they did not report frequency of all alleles and genotype, and relationship between other genes and essential hypertension and studies which investigated the role of ACE I/D in other diseases.Variables were extracted using checklist from all studies. The following study characteristics were recorded in our study: first author’s surname, year of publication, ethnicity of study population, number of cases and controls for ACE I/D genotype. Gene, polymorphism, and frequencies of D and I allele were computed for case and control groups from the corresponding genotype distribution. Two authors independently conducted the data extraction and synthesis, with any discord resolved through discussion.2 statistics. Q statistic (significance level at p<0.05) was also determined. I2 <25% minimal heterogeneity, 25–75% moderate heterogeneity and >75% extreme heterogeneity. The pooled ORs were computed using either fixed-effects model or random-effects model. Random effect model was used if the studies had heterogeneity and if there no fixed effect model was used.Odds ratio (OR) and 95% confidence interval (CI) was used to measure the strength of the association between ACE I/D gene polymorphism and essential hypertension across studies. Heterogeneity was measured by Ip<0.05). A sensitivity analysis was conducted by subsequent omission of individual studies and looked for the difference in change of OR and its associated significance. Potential publication bias was assessed by Egger’s test (significance level at p<0.05). All analyses were conducted using the Web tool META-Genyo, Version 12.0. [Different genetic models were used to compare the genotypes and alleles. Allele contrast model (D vs I), recessive model, dominant model, overdominance, as well as homozygous and heterozygous co-dominance models were used. Forest plot was conducted for all models to identify the individual and pooled effect of all studies included in this meta-analysis. Agreement of the genotype frequencies to Hardy–Weinberg equilibrium (HWE) was tested using chi square  and 4 from North Africa (three Egypt and one Tunisia), met the inclusion criteria. Sample size ranged from 61 to 1224. Mean age (±sd) of the studied populations were between 45 (±8.2) and 62.8 (±9.9) for cases and 31.9 (±10.27) to 54.4 (±9.5) for controls. Mean (±sd) blood pressure for the participants were different among the included studies. One study did not report blood pressure . The meaAll studies had higher frequencies of the DD genotype compare to DI and II genotypes in the hypertensive group; whereas, in the control group, the distribution varied depending on the study. There was no violation of HWE in any included studies .2 >50%. The sources for the heterogeneity might be in the difference in sample size and difference in the geographical areas where the studies were conducted  which relate to ethnicity. ACE deletion/insertion polymorphism was significantly associated with essential hypertension in the allele contrast model (P = 0.01) showing significant heterogeneity (P = 0.0001) and no publication bias (P = 0.32); the recessive model (P = 0.03) showing significant heterogeneity (P = 0.0001) and no publication bias (P = 0.46); and the dominant model (P = 0.032 and with non-significant heterogeneity (P = 0.12) or publication bias (P = 0.28); and the homozygote codominant model (P = 0.018) with significant heterogeneity (P = 0.008) and no publication bias (P = 0.30). In the remaining models, the ACE I/D polymorphism gene did not have significant association with essential hypertension , dominant model (DD+ID vs II), and homozygote co-dominant model (DD vs II). Since there was heterogeneity across the studies, the random effect model was used to estimate the odds ratio. Patients with D allele were 1.49 times higher to develop essential hypertension compared with those who carry the I allele . Similarly, patients with homozygous codominance genotype (DD) are at a 2.17 times higher risk of essential hypertension compared to those with the co-dominant genotype II , dominant model (DD+ID vs II)  and recessive model  .A subsequent sensitivity analysis by omission of studies was done to check for instability and change in significance of the effect estimate. After each study was excluded from the current meta-analysis, as can be seen from the graph, there was no significant shift or change in the level of significance and odds ratio. Studies by Mary et al. , DamehanClick here for additional data file.S1 Database(DOCX)Click here for additional data file.S1 Articles(DOCX)Click here for additional data file.


Allele *1 has a single copy of a 19‐bp sequence in the 5` untranslated region (5`UTR), but allele *2 contains tandem repeats of 19‐bp sequence.Lysosome‐associated protein transmembrane‐4 beta (LAPTM4B) has two alleles named as LAPTM4B*1 and LAPTM4B*2  Original case‐control studies that evaluated the LAPTM4B polymorphism and the risk of cancer; (b) studies provided sufficient information of the genotype frequencies of LAPTM4B polymorphism in both cases and controls. The exclusion criteria were: (a) conference abstract, case reports, reviews, duplication data; (b) insufficient genotype information provided.LAPTM4B polymorphism, the sample size, and the genotype and allele frequencies of cases and controls . For each study, Hardy‐Weinberg equilibrium (HWE) was determined by the chi‐squared test, in order to verify the representativeness of the study population.Meta‐analysis was carried out using Revman 5.3 software  and LAPTM4B polymorphism in relation to cancer risk was evaluated by pooled odds ratios (ORs) and their 95% confidence intervals (CIs). Pooled ORs and their 95% CIs for codominant, dominant, recessive, overdominant and the allelic comparison genetic inheritance models were calculated. The significance of the pooled OR was assessed by the Z test, and P < 0.05 was considered statistically significant. The choice of using fixed or random effects model was determined by the results of the between‐study heterogeneity test, which was measured using the Q test and I2 statistic. If the test result was I2 ≥ 50% or PQ < 0.1, indicating the presence of heterogeneity, the random effect model was selected; otherwise, the fixed‐effects model was chosen.The association between P < 0.05 was considered significant publication bias. To measure the potential influence of each study on the overall effect size, sensitivity analysis was performed.The funnel plot was used to estimate the publication bias. The degree of asymmetry was measured using Egger's test; 3LAPTM4B polymorphism and cancer susceptibility cancer in codominant , dominant , recessive , overdominant , and allele  inheritance model tested .P‐values for bias >0.05). We executed sensitivity analysis by neglecting a single study each time to reflect the influence of the individual data set to the pooled OR. The results indicated that the significance of pooled ORs for LAPTM4B polymorphism was not extremely influenced, suggesting the stability and reliability of the results in this meta‐analysis.The potential publication bias was evaluated using a Begg's funnel plot and Egger's test and the analysis suggested no publication bias for this meta‐analysis of the heterozygous codominant, dominant, recessive, overdominanat, and allele model (all 4In the current study, we performed a meta‐analysis to find out the exact role of LAPTM4B polymorphism on risk of cancer. The results revealed that LAPTM4B polymorphism significantly increased the risk of cancer in codominant, dominant, overdominant, and allele genetic inheritance models. Stratification by cancer types suggested that LAPTM4B polymorphism is associated with the risk of breast cancer, gynaecological cancer, gastrointestinal cancer, liver cancer, lung cancer, and lymphoma. LAPTM4B is a proto‐oncogene that is overexpressed in various types of cancers. It has been proposed that overexpression of LAPTM4B‐35 promote proliferation, invasion, and migration. Its up‐regulation might be caused by gene amplification as well as transcriptional up‐regulation. LAPTM4B alleles have the same sequence except for one 19‐bp fragment for LAPTM4B *1 and two tight tandem fragments for LAPTM4B *2 in the 5′UTR of exon 1.The authors declare no competing of interests.


GSTA1, GSTM1, GSTP1 and GSTT1 genotypes and explored their individual and combined effects in individuals with ASD. Individual effect of GST genotypes was shown for GSTM1 active genotype decreasing the risk of ASD , and for GSTA1 CC genotype, increasing susceptibility to ASD ; the significance was lost when genotype-genotype interactions were added into the logistic regression model. The combination of GSTM1 active and GSTT1 active genotype decreased the risk of ASD , as well as combination of GSTT1 active and GSTP1 llelle . Increased risk of ASD was observed if combination of GSTM1 active and GSTP1 llelle was present . The effect of TSDP was not significant for the risk of ASD, neither individually, nor in interaction with specific GST genotypes. Specific combination of GST genotypes might be associated with susceptibility to ASD, while it appears that maternal smoking during pregnancy does not increase the risk of ASD.Autism spectrum disorders (ASD) are a group of complex psychiatric disorders, with a proposed gene-environment interaction in their etiology. One mechanism that could explain both the genetic and environmental component is oxidative stress. The aim of our study was to investigate the potential role of common polymorphisms in genes for glutathione transferase A1, M1, T1 and P1 in susceptibility to ASD. We also aimed to explore the possible oxidative stress - specific gene-environment interaction, regarding GST polymorphisms, maternal smoking tobacco during pregnancy (TSDP) and the risk of ASD. This case-control study included 113 children with ASD and 114 age and sex-matched controls. The diagnosis was made based on ICD-10 criteria and verified by Autism Diagnostic Interview – Revised (ADI-R). We investigated  Epidemiological analyses showed that the prevalence of ASD has increased for 23% in the past 10 years2. The rise in prevalence could be accounted for by the recent changes in registering and diagnosis of ASD3, but also by the mechanism of gene-environment interaction4. The phenotypic manifestations of ASD are largely heterogeneous, which might be explained by complex interaction of genetic susceptibility with different risk factors, leading to an individual path of developing ASD in each person. The data of previous studies show that the period of susceptibility to environmental factors in ASD, might be the prenatal and perinatal period of development5. There have been many studies focused on the aforementioned issue, thus some of the main potential prenatal and perinatal risk factors have been well defined8.Autism spectrum disorders (ASD) represent a group of disorders which include symptoms such as impairment of social interactions, impairment of communication  and restricted interests and repetitive behavior11.It is hypothesized that superfamily of glutathione transferases (GSTs), enzymes that are not only responsible for catalyzing detoxification reactions, but also are important as part of antioxidant defense system and in cellular signaling, might contribute to the development of ASD12, and also to oxidative stress13.The explanation for the assumption lies in the fact that GSTs or, more precisely, genetic polymorphism observed in almost all classes of GST superfamily, might increase the individual susceptibility to environmental factors associated with ASDet al. (2007) who noted higher risk of ASD in children of women with GSTP1 Ile/Val genotype, further suggesting that risk factors during pregnancy might result in higher risk of ASD in later life10.Glutathione transferases, as part of gene-environment interaction in development of ASD, were mentioned a decade ago by Williams 14. Moreover, another study has shown a possible interaction between GSTP1 polymorphism (GSTP1 Ile/Ile genotype) and the effect of blood manganese concentration11, but also between GST polymorphisms and exposure to aluminum15. Available data on other GST genotypes are scarce, still GSTM1 null and GSTT1 null genotypes, alone or in combination with GSTP1 polymorphism, have been associated with risk of ASD18. Interestingly, GSTA1 genotype has not been evaluated in terms of ASD susceptibility as yet.In recent years, significantly increased levels of lead and mercury, as well as a decrease of GST activity were noted in patients diagnosed with ASD, when compared to typically developed controls21, also suggested the role of glutathione transferases in ASD development, in particular when taking into account the important antioxidant role of GSTs22.Multiple lines of evidence which suggested that oxidative stress could represent the basis for the observed association between genetic, immunological and environmental factors underlying autism23, factors known to be also associated with ASD25. TSDP has also been associated with epigenetic changes in the offspring, which persist well into adulthood26. Moreover, a study by Hultman et al. (2002) confirmed that TSDP might indeed be a risk factor associated with ASD27. Furthermore, multiple studies confirmed the association between “second hand” smoking and ASD28. The aforementioned findings were somewhat controversial as a large study by Maimburg&Vaeth (2006) didn’t show evidence that TSDP increases the risk for ASD29. What is more, a meta-analysis done in 201530 also showed no association between maternal TSDP and risk for ASD. This meta-analysis included 15 cohort and case-control studies, and involved only those that examined active TSDP. The authors argued, despite the fact that several plausible hypotheses might explain the association between maternal smoking and ASD, and it would be expected to be significant, the results were negative30. A recent large population study done in Sweden has shown association of TSDP and severe mental disorders (bipolar disorder and schizophrenia), but further analysis showed that this association weakens significantly after using the family based approach to estimate the risk. The authors point to a possible influence of a hidden familial confounding factor, such as passive gene-environment interaction31. One of the possible explanation for conflicting results in studies focused on association between TSDP and ASD could be clarified by the individual susceptibility to those factors. The susceptibility might have genetic variation as an underlying mechanism. Namely, genetic polymorphism with consequential lack or change in the activity of enzymes involved in detoxification of tobacco smoke, a rich source of free radicals and numerous carcinogens, might represent the determinant of this individual susceptibility. In this line, GSTA1, GSTM1 and GSTP1 participate in conjugation of tobacco smoke metabolites with glutathione, thus enhancing their excretion in urine, while due to strong peroxidase activity they are among key components in cellular defense against free radical damage33.One of the explored prenatal risk factors in recent studies is smoking tobacco during pregnancy. Tobacco smoking during pregnancy (TSDP) has been associated with numerous adverse events, such as preterm birth and low birth weightin utero is air pollution, known to contain various airborne toxicants and contaminants capable of inducing oxidative stress and mitochondrial damage in vitro35. Similarly to tobacco smoke, genetic variations influence individual capability for protection from air pollution.Another environmental factor which can be associated with neurotoxicity and adverse effects on the fetus 13 might help resolve the complex etiology of ASD, we aimed to investigate the association between common polymorphisms in genes encoding cytosolic glutathione transferase A1, M1, T1 and P1 and ASD. We also aimed to explore the possible oxidative stress - specific gene-environment interaction, regarding GST polymorphisms and TSDP and the risk of ASD.Considering the fact that identifying new specific gene-environment interactions, as well as, elucidating in which way antioxidants contribute to redox imbalance in autism36, confirmed by a child psychiatrist with experience in diagnosing ASD. The evaluation was done through clinical interview with a parent and examination of a child. Besides clinical interview and criteria, the diagnosis was verified by the Autism Diagnostic Interview – Revised (ADI-R)37, conducted by a trained child psychiatrist.The study was performed as a case-control study. The case group involved 113 ASD patients , included as consecutive referrals and treated as outpatients and inpatients at the Institute of Mental Health, Belgrade, Serbia. The inclusion criterion for the case group was the presence of any of the ASD. The diagnosis was verified by the ICD-10 criteriaThe control group consisted of 114 age and sex group-matched controls, recruited from the Urology and Orthopedic Department of University Children’s Hospital, Belgrade, Serbia. Control subjects suffered from unintentional injuries (fractures) and urogenital tract disorders , and were selected consecutively, at the same time at which cases were collected. The exclusion criterion for controls was personal or family history of neurological or psychiatric disorder, as well as any kind of developmental delays. The difference in age and sex distribution within the group level was not statistically significant.(ADI-R)37. ADI-R is a standardized semi structured parent/caregiver interview, created for the assessment of signs of ASD. It comprises 93 items, and evaluates child’s early development, development of language, functioning of language and communication, loss of speech and motor skills, social development and play, interests and behavior. The description for each item, given by the parent/caregiver is made for childhood (ever) and current behavior. Specific items describing social reciprocity, communication and restricted, repetitive and stereotyped behavior (RRSB) are used to reach the scores for these three domains . Higher scores account for greater impairment – worse symptoms. In this study, the interview was administered by certified child psychiatrists.The questionnaire was created specifically for the current study, and was administered to parents of cases and controls likewise. Besides the basic sociodemographic information, our questionnaire explores different types of prenatal exposures as well as perinatal complications in participants of the study. The questionnaire was administered during study period and comprized questions regarding presence and quantity of specific exposure.QIAamp DNA Blood Mini Kit , in accordance with the manufacturers protocol. Genotyping was performed blinded to the case-control status. Blinded quality control samples were applied for validation of genotyping procedures. Concordance for the blinded samples was 100%. All of the assays included positive and negative controls. All primers used are synthesized and bought from Metabion International AG 38.Total DNA was isolated from 200 µl of the whole peripheral blood using Abdel-Rahman et al.39 was done for assessing the presence of amplified PCR products of GSTM1: 215 bp, GSTT1: 481 bp, as well as housekeeping gene CYP1A1: 312 bp, which was applied as internal control. It is important to emphasize that the assay does not make a distinction between heterozygous or homozygous wild-type genotypes. Therefore, it notes only the presence  or the absence  of the specific genotype. PCR products were visualized on Chemidoc .Multiplex polymerase chain reaction (PCR) method of GSTA1*C69T(rs3957357) was performed using PCR-restriction fragment length polymorphism (RFLP) by method of Ping et al.40. A 400 bp fragment was amplified and subjected to overnight incubation at 37 °C with enzyme EarI . Digested products  were visualized on Chemidoc .The analysis of the SNP GSTP1 Ile105Val, TaqMan® SNP Genotyping Assays  was performed for amplifying and detecting respective SNP alleles in purified genomic DNA samples, complying to the manufactures’ instructions. DNA concentration and purity were analyzed spectrophotometrically using GeneQuantpro . The presence of GSTP1 Ile/Ile genotype was defined as GSTP1-wild type, whereas the presence of GSTP1 Ile/Val or GSTP1 Val/Val genotype as GSTP1 variant genotype.For assessment of SNP polymorphism 2 and t test were used to test possible differences between case and control group on several control variables. The χ2 test was also used for the assessment of possible genotype departure from Hardy-Weinberg equilibrium. Three binary logistic regression models were used to test the predictive effects on ASD, with the following sets of predictors: (1) individual genotypes, (2) individual genotypes and genotype-genotype interactions, and (3) individual genotypes, genotype-genotype interactions, maternal smoking status during pregnancy and smoking- genotype interactions. As effect size indicators we used odds ratio , percentage of correct classification and Nagelkerke r2. The probability level of ≤0.05 was considered statistically significant. For statistical analysis the SPSS 17.0 statistical software package  was used.Statistical analysis included, besides descriptive statistics, nonparametric and parametric tests depending on the variable type. χThis study has been approved by the ethics committee of the Institute of Mental Health, University Children’s Hospital and Faculty of Medicine, University of Belgrade, Serbia, and has been performed in accordance with the principles of good clinical practice. Prior to participation in this study, parents/caretakers signed the informed consent.Baseline characteristics of ASD cases and respective controls are shown in Table GSTM1 active genotype decreased the risk for ASD  compared to GSTM1 null genotype. It seems that polymorphisms in GSTT1 and GSTP1 genotypes did not contribute to ASD risk. Regarding GSTA1 genotype, carriers of GSTA1 CC genotype were at increased risk for ASD  compared to carriers of GSTA1 CT and GSTA1 TT genotypes. Percentage of correct classification was 62.5% with Nagelkerke r2 = 0.079  variants have not deviated from expected distribution. Binary logistic regression was used to test possible prediction of ASD based on individual genotypes. Obtained results showed that GSTM1 active and GSTT1 active decreased the risk of ASD , as well as the combination of GSTT1 active and GSTP1 llelle . On the other hand, increased risk of ASD was noticeable if combination of GSTM1 active and GSTP1 llelle was present . Other interactions of genotypes did not cross the level of statistical significance. Percentage of correct classification increased a bit in comparison to effects of individual genotypes (65.7% with Nagelkerke r2 = 0.202).After obtaining individual effects, we were also interested in combined effect of any two genotypes Table . We alsoGST genotype , as well as combination of GSTT1 active and GSTP1 llelle , while combination of GSTM1 active and GSTP1 llelle increased the risk of ASD . Other interactions of genotypes did not cross the level of statistical significance. The most important finding is that neither effect of smoking during pregnancy per se, neither it’s interaction with any of the genotypes crossed the level of statistical significance. Smoking during pregnancy did not show any effects on the risk of ASD in our study. Percentage of correct classification was similar as in previous analysis which included all effects except smoking during pregnancy (66.3% with Nagelkerke r2 = 0.270).We further assessed the effect of smoking during pregnancy in relation to pe Table . By binaGSTM1 null and GSTA1 CC genotypes were significantly more frequent in patients with ASD. To the best of our knowledge, these are the first results presented in the literature focused on clarifying the association of individual GSTA1 polymorphism and ASD. On the other hand, GSTM1 active genotype seems to be protective in terms of ASD development. Similarly, combined GSTM1 active and GSTT1 active genotype, as well as, combined GSTT1 active and GSTP1 IleIle genotype also decrease ASD risk. Another interesting finding is the observed effect of GSTM1 active and GSTP1 IleIle genotypes which were significantly associated with susceptibility to ASD.The present study investigated polymorphic expression in four classes of glutathione S-transferases  in individuals with ASD, as well as their possible gene-gene and gene-environment interaction underlying this disorder. The results of this study showed that the 4, however, so far only several studies evaluated the possible association between GST polymorphisms, as independent factor , and susceptibility to ASD17. Cytosolic GST family catalyzes the conjugation of electrophilic compounds, including products of oxidative stress, with GSH9. Polymorphisms within GST classes result in complete lack or altering of enzyme activity, hence altering both the capacity for detoxification of different endogenous and exogenous compound, including oxidants, and in that way contributing to development of various neurological and mental disorders, along with ASD44.Over the years, many studies have attempted to elucidate triggering genetic factors in the development of ASDGSTM1 and GSTT1 deletion polymorphisms, which, in carriers of GSTM1 null or GSTT1 null genotype, affect cell’s ability to metabolize toxins due to complete lack of active enzyme33. Several studies found increased ORs for ASD in carriers of GSTM1 null genotype alone or in combination with other genetic factors18. Our findings on increased GSTM1 null genotype frequency among cases in comparison to controls, together with protective role of GSTM1 active genotype in ASD development are in agreement with a study by Buyske et al.18, while the study by Rahbar et al.17, didn’t show this result. Although this significance was not shown when genotype and genotype interactions and TSDP were added into the model, GSTM1 active genotype showed significant interaction with GSTT1 active genotype, significantly decreasing the risk for ASD, as well as with GSTP1 IleIle genotype, with the opposite effect.The emphasis regarding GST polymorphisms in autism spectrum disorders has been put on GSTT1 null genotype, which might be considered as either risk-associated or protective in certain disorders,. Namely, it is well established that GSTT1 enzyme is involved in bioactivation, rather than detoxification of several bifunctional alkylating agents, present in environmental pollution and certain occupational hazards45. So far, the possible association between GSTT1 genotype and ASD was investigated only in one study in which no association between individual GSTT1 genotype and risk of ASD development was observed17 and our results are in agreement with this finding. However, we found that the combination of GSTT1 active genotype might act protectively in combination with specific GST genotypes. Our results show that the combinations of GSTT1 active and GSTM1 active genotype, as well GSTT1 active with GSTP1 IleIle genotypes, decrease the risk for ASD. Similar to our results, the combined GSTT1 null and GSTP1 IleIle or IleVal genotype was recognized as significant in terms of risk of ASD in Jamaican population17.The other GST deletion polymorphism, as mentioned, results in 45, is specific for its substrate promiscuity as a consequence of protein flexibility and dynamics in the enzymes active site46. It also possesses peroxidase activity towards organic hydroperoxides and might be involved in regulation of cellular redox homeostasis, and therefore it is interesting that to date, it has not been analyzed in ASD. Moreover, Iorio et al.47 provided evidence supporting the notion that GSTA1 may play an important role during pregnancy, since previous studies indicated that GSTA1 polymorphism is associated with different pregnancy-related conditions50. Polymorphism of GSTA1 is represented by three linked single nucleotide polymorphisms (SNPs), resulting in differential expression with lower transcriptional activation of the variant GSTA1*B (T) than the common GSTA1*A (C) allele33. Results of this study have shown that carriers of GSTA1 CC genotype, with the highest expression of GSTA1 enzyme, are in increased risk of developing ASD when compared to individuals with GSTA1 CT and TT genotype. The possible explanation for the observed associations might be in the fact that, similarly to GST theta class, alpha class also participates in bioactivation of several drugs and certain neurotoxic compounds51. This significance was lost in further analysis, both for individual and combined effect of GSTA1 genotype status.Alpha class of GSTs, which is expressed in most tissues, including brainGSTP1 IleVal genotype10, as well as, in carriers of GSTP1 wild type genotype depending on blood manganese concentration or exposure to aluminum15.Another important SNP in glutathione S-transferase superfamily is GSTP1 polymorphism, which has been suggested as contributing factor in ASD development years ago. As mentioned, the risk of ASD was observed in offspring of mothers with GSTP1 genotype with ASD, while it seems that in combination with other GST polymorphisms GSTP1 IleIle genotype contributes differentially to the effect on ASD. The lack of association of individual GSTP1 genotype with ASD has also been shown in the study by Rahbar et al.17. Still, the interaction of GSTP1 IleVal with GST1 null genotype was shown to be significant in the Jamaican sample17. Also, it was shown that GSTP IleIle genotype interacts with blood manganese levels – it was proven that this genotype increased the risk of ASD significantly, in children with high manganese blood levels11. Our results show that GSTP1 IleIle genotype was significant in interaction - with GSTT1 active decreasing the risk of ASD, and with GSTM1 active genotype increasing the risk. The role of GSTP1 genotypes has been shown in several complex disorders, showing complex interactions17. Further studies with emphasis of GSTP1 genotypes and other genetic and environmental factors could elucidate its role in complex disorders such as ASD.Results of our study failed to associate individual GST gene variants and exposure to cigarette smoke metabolites. This possible gene-environment interaction seems to be biologically plausible, since it has been shown that GSTP1 Val allele is more catalytically efficient towards benzo-diol-epoxides found in tobacco smoke52. Also, glutathione S-transferases are involved in detoxification of both free radicals and reactive polycyclic aromatic hydrocarbon metabolites, all present in cigarette smoke33. Namely, due to the fact that GST enzymes belonging to various classes have different, but sometimes overlapping, substrate specificities, their contribution in tobacco smoke metabolism and cellular antioxidant defense must be taken into account32. The surprising result was that neither the effect of smoking during pregnancy per se, nor it’s interaction with any of the genotypes showed any effects on the risk of ASD. A recent meta-analysis showed that maternal smoking during pregnancy is not associated with ASD risk in offspring30, which is in line with our finding. Although the possible interaction between TSDP and GST genetic polymorphisms might explain the inconsistency in results of studies on association of TSDP and risk of ASD30, our study has not confirmed the hypothesis. To our knowledge, this is the first study to examine this gene-environment interaction in ASD.We further tried to explore whether there is any gene-environment interaction between different Our study has strengths and limitations. The strength of our study is the fact that, to our knowledge, this is the first study that examined GSTA1 genotypes in risk for ASD. Also, this is one of the rare studies that examined not only individual, but also combined effects of specific GST genotypes on risk for this group of disorders.Certain limitations might also be considered in our study. The case–control design was used for estimating of associations between individual and combined GST genotypes and increased risk for ASD, and therefore the selection bias might influence the results. Furthermore, our control group was hospital-based and relatively small; therefore, the use of population controls might have been more appropriate. In this line, the possible effect of ethnicity could not be evaluated since the study subjects were Caucasian only. Therefore, further genotyping, using a larger sample size, is needed to better understand association between GST gene variants, relevant environmental exposures and increased risk for ASD. It is of note that in case of the GSTP1 variant we have observed deviation from Hardy-Weinberg equilibrium. Although this deviation could be due to relatively small sample size, our results for GSTP1 must be taken with caution and future studies will be needed to comprehensively assess the effect of this variant.Taken together, polymorphic expression of glutathione S-transferases might influence individual susceptibility to autism spectrum disorders, especially taking into account different oxidative stress-specific gene-environment interaction. If it could be possible to identify persons at higher risk of ASD based on specific oxidative stress genotype, possible preventive actions might be taken.Still, the presence of different GST gene variants needs to be analyzed in conjunction with other genetic and environmental risk factors. That way, the fact that a certain prenatal factor has not been firmly associated with the increased risk of ASD in the general population does not exclude the possibility that there is a sensitive subpopulation (genotype wise).


Coffee is a blend of compounds related to gastrointestinal physiology. Given its popularity and the epidemiology of colorectal cancer, the impact of this beverage on public health could be considerable. Our aim was to provide an updated synthesis of the relationship between coffee consumption and the risk of colorectal cancer. We conducted a systematic review and meta-analysis of 26 prospective studies. Regarding colorectal cancer, no significant relationship was detected. Stratifying for ethnicity, a protective effect emerged in US subjects. Concerning colon cancer, coffee proved to exert a protective effect in men and women combined and in men alone. Stratifying for ethnicity, a significant protective effect was noted in European men only and in Asian women only. Concerning rectal cancer, no association was found. Decaffeinated coffee exhibited a protective effect against colorectal cancer in men and women combined. Studies were appraised for their quality by means of the Newcastle-Ottawa Quality Assessment Scale for Cohort studies. Only one study proved to be of low quality. Ethnicity could explain the heterogeneity of the studies. However, little is known about the relationship between the genetic make-up and the risk of colorectal cancer associated with coffee. Further research is warranted. Coffee is a complex blend of bioactive compounds. These are related to gastrointestinal physiology in various ways and may exert contrasting effects. On the one hand, coffee contains anti-oxidants and anti-mutagens, which could, as such, reduce exposure of the epithelial cells of the bowel to carcinogenic chemicals and compounds, and prevent and counteract the effect of potential promoters of intestinal carcinogenesis. Indeed, coffee seems to enhance bowel motility and functioning, reducing fecal transit times and increasing stool output. Furthermore, coffee contains lipidic compounds, such as cafestol and kahweol, which, by finely tuning cholesterol metabolism, reduce the synthesis and release of bile acids . They acMoreover, the quantity of these bioactive compounds varies according to the type of coffee. For example, unfiltered coffees, such as French press coffee or Turkish/Greek coffee, contain significant amounts of these compounds, unlike filtered blends, such as dip-brewed coffee. Moreover, filtered coffee also contains fewer phenols and polyphenols ,9.Being cheap and easy to prepare, coffee is a widespread beverage, its worldwide consumption of two billion cups per day being second only to that of water . Given tThe Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) guidelines  were useInclusion criteria were: (1) articles with relevant quantitative details and information on the relationship between coffee consumption and the risk of developing colorectal cancer; (2) prospective studies. Exclusion criteria were: (1) items not directly pertinent to the query string; (2) articles not containing sufficient information on the relationship between coffee consumption and the risk of colorectal cancer; (3) articles not meeting the PICOS criteria ; all such articles were consequently discarded. No time filter or language filter was applied. For further details of the search strategy, see Two of the authors independently screened the literature. Any case of disagreement was solved by discussion until consensus was reached. After the full text review, the papers included were retained for data extraction.Data for the meta-analysis were extracted from the studies included by means of a standardized documentation form. The parameters extracted were: the surname of the first author, the year and country of publication, sample size, percentages of females and males, incidence of colorectal cancer , and the amount and type of coffee consumed. RR of developing colorectal cancer on the basis of coffee consumed  were calculated as effect size estimates, with their 95% confidence intervals (CIs). Additional analyses were performed after stratification by type of coffee, study region, publication period and gender. Study quality was appraised by two researchers, working independently, with respect to the appropriateness of the research questions tested and of the methods employed. For this purpose, the Newcastle-Ottawa Quality Assessment Scale for Cohort studies (NOS) was used; scores of ≥7 indicated high-quality and <7 indicated low-quality studies. Any disagreement was solved by consensus. 2 statistics and chi-square test, heterogeneity being deemed significant if the p value (χ2) was <0.1. In detail, it was determined that the values of 25%, 50% and 75% in the I2 test corresponded to low, moderate and high levels of heterogeneity, respectively. In the event of significant (moderate or high) heterogeneity among the studies, a random-effects model was used for the meta-analysis. The RR of the meta-analyses were deemed significant when the confidence intervals did not contain the value “1”; indeed, if the confidence interval contains the value “1”, we cannot exclude the absence of an association between exposure and disease. A narrower CI than that of the individual studies indicates less imprecision. Statistical heterogeneity was also assessed in our meta-analysis by means of IR  software. To identify sources of variation, further stratification was performed with respect to study quality. In addition, in the sensitivity analyses, the stability of the pooled estimate with respect to each study was investigated by excluding individual studies from the analysis. Possible publication bias was visually inspected by means of a funnel plot. If asymmetry was detected by visual assessment, exploratory analyses using trim and/or fill analysis were performed in order to investigate and adjust the effect-size estimate. In addition, the probability of publication bias was tested by means of Egger’s linear regression, a value of p < 0.05 being indicative of publication bias.Meta-analyses were carried out by means of the STATA SE14Concerning the systematic review, our initial query resulted in 390 hits ; after removal of duplicate items, the resulting list comprised of 270 non-redundant articles. Only 33 studies were retained in the qualitative synthesis, and 26 were finally considered in our systematic review and meta-analysis (186 articles were discarded as not being directly pertinent to the topic under investigation and 51 as not meeting the inclusion criteria). For further details, see The full list of studies included ,35,36,37The studies examined included 3,308,028 subjects. Eleven studies were performed in European countries, seven in Asian countries and seven in the USA. Nineteen studies were on colorectal cancer, 19 on colon cancer and 18 on rectal cancer.With regard to colorectal cancer, from the pooled RR, no significant relationship between coffee consumption and the risk of developing cancer was detected . Stratifying for ethnicity, a significant protective effect emerged among US subjects (men and women), with a RR of 0.83 (95% CI 0.72–0.95). While no statistical significance emerged for caffeinated coffee, decaffeinated coffee exhibited a protective effect on men and women combined (RR 0.88 (95% CI 0.78–0.97)).Concerning colon cancer , coffee Stratifying for ethnicity, a statistically significant protective effect was noted in European men only (RR 0.85 (95% CI 0.72–0.99)), and in Asian women only (RR 0.73 (95% CI 0.58–0.88)) A,B.Focusing on distal colon cancer , coffee Concerning rectal cancer , no signNo significant publication bias was detected. Finally, concerning the assessment of the risk of bias, no significant biases emerged. Only one study was deemed to be of low quality (Wu: NOS score = 5). Retaining or removing this study from the meta-analyses did not change the results.Performing the meta-analysis of prospective studies, we found a significantly high degree of heterogeneity. With specific regard to rectal cancer, no evidence of an association between coffee consumption and the development of the disease could be found. For colorectal cancer, we found evidence of a protective effect only in US men and women together. Stratification by type of coffee—caffeinated or decaffeinated—did not reveal any differences linked to the presence of caffeine, since the types of coffee appeared to be protective in some studies and non-significant in others. Moreover, the quantity of caffeine in coffee also depends on the type of mixture used , a paramRegarding colon cancer, evidence of a protective effect of coffee consumption was found, both considering men and women together and considering men alone. Stratifying for ethnicity, we found that the pooled RR was significant for European men and for Asian women. We can speculate that this might be due to the particular type of coffee consumed; for example, in Asia, coffee is rarely consumed boiled or decaffeinated . AnotherAs potential mechanisms that may explain the inverse association between coffee consumption and the development of colon cancer, a review by Higdon  hypothesA major limitation of the present meta-analysis lies in the fact that most studies did not specify whether the coffee blend was caffeinated or decaffeinated, filtered or unfiltered, thus hindering the possibility of precisely stratifying the pooled RR according to the type of coffee consumed.A major difficulty in interpreting epidemiological data is that studies often do not clearly indicate the quantity of coffee consumed ; estimates are therefore “rough”. Moreover, the considerable variability in the composition of the beverage makes it difficult to accurately determine the potential quantity of bioactive substances involved in the process.The development of colorectal carcinoma is a complex, multi-step process characterized by a series of both genetic and epigenetic changes, which involve different cellular cascades and pathways, including DNA repair, proliferation, apoptosis, intra- and extracellular signaling, and adhesion, among others . EthniciIn conclusion, the available studies are not sufficient to define a protective role of coffee against colorectal cancer.


Down’s syndrome (DS) affects one per 700 live births and congenital heart disease (CHD) occurs in 40–60% of these patients. Contributing factors to the association between DS and CHD are being unraveled. Gender could be one of them.We performed a meta-analysis of CHD prevalence in DS, separated by gender. Three search engines were used and 578 articles were reviewed. Twelve articles were included.Quantitative analysis showed a higher prevalence of CHD, particularly atrioventricular septal defects (AVSD), in female patients. No differences were found in others forms of CHD.CHD, particularly AVSD, are more common in the female gender of Down’s syndrome patients.The online version of this article (10.1186/s12881-017-0475-7) contains supplementary material, which is available to authorized users. Down’s Syndrome (DS) affects one in each 700 live births , 2. Its It is well known that DS is a risk factor for CHD. In these patients, the most frequent forms of CHD are atrioventricular septal defects (AVSD), ventricular septal defects (VSD) and atrial septal defects (ASD) , 7. The In this context, gender could influence the presence and type of CHD. Some studies point out a higher predominance of male gender in patients with DS , 21, butThe purpose of this study was to compare the prevalence of CHD and DS between genders through a meta-analysis and systematic review.Studies that described the prevalence of CHD in DS by gender were included. Studies where this information was not available were excluded.The search for articles was performed using the following data engines: Medline (accessed via Pubmed), Scopus and Scielo. Terms included were those used by Mesh for Medline and Scopus, and the descriptors of Health Sciences (Decs) for Scielo. Terms included: “prevalence”, “Down syndrome” and “congenital heart disease”. Additional file Two authors (Mattos and Mourato) evaluated the title and abstracts of the identified articles. The complete texts of the selected abstracts were obtained and posteriorly analyzed by the same authors. After this initial analysis, each selected article’s information were added to a database. The authors agreed that discordances about the inclusion of an article should be sorted by consensus. However, there were no disagreements. Duplicated studies were excluded.Gender prevalence was calculated by dividing the total number of DS patients with CHD by the total number of DS for each gender. The prevalence of AVSD, ASD, VSD, PDA (patent ductus arteriosus) and TOF  were calculated dividing the number of DS with each cardiac defect by the total number of patients with DS in the study. A combined data analysis was performed to identify the Odds Ratio between genders, being the female gender considered a risk factor. The confidence intervals and the size of the pondered effect were calculated and the meta-analysis graphs built using the MedCalc v 16.8 software.2, which describes the variability, not related to sample errors, in the studied population. An I2 beyond 75% is consistent with high heterogeneity. As such, the meta-analysis should be carried out using the fixed model if the heterogeneity analysis resulted in number constantly inferior to 75% and using a random effects model if it resulted in a number equal or superior to 75% . The Mantel-Haenszel method was used for calculating the weighted summary Odds ratio under the fixed effects model. Subsequently, heterogeneity statistics were incorporated to calculate the summary Odds ratio under the random effects model (in accordance to I2 statistics).Heterogeneity between studies was calculated using the IFrom the engine database sources, 595 abstracts were selected. Initial review identified 35 for full text analysis. From this latter group, only four fulfilled the eligibility criteria and were included in the meta-analysis –25. DireAfter the meta-analysis, it was observed that female gender is a risk factor for the presence of CHD in DS Fig. . The samThe frequency of CHD in this systematic analysis is in accordance with other studies involving DS , 31–35. Various theories exist to explain the origins of CHD in DS. Some authors suggest that the presence of certain variants in specific genes could be the underlying cause for CHD in this population , 36. OthIn this meta-analysis, we observed a higher frequency of CHD in the female gender . This finding suggests that this gender is more susceptible to CHD in DS. Another finding that supports this conclusion is that AVSD, alone, also showed a higher frequency in female gender ; and this form of CHD is more prevalent in DS than the general population ). Other This meta-analysis had some limitations. First, it included only articles from three databases . This can lead to no identification of minor or locally published studies, whose inclusion could alter some of the findings presented herein . Second, the populations included in this paper are rather different among themselves. For example, Morris et al. included data from 20 European Countries, and of both live births and abortions after the 20th week . It is kThis brief meta-analysis demonstrated higher prevalence of congenital heart disease, particularly AVSD, on female patients with Down syndrome.Additional file 1:Search strategy in Pubmed. Contains the terms and strategy to find the main articles of this meta-analysis in Pubmed. (DOC 51 kb)Additional file 2:Raw data. Contains the raw data obtained from the articles for congenital heart disease and Down syndrome prevalence by gender. (DOCX 11 kb)


Background: C-reactive protein (CRP) has been identified as a common inflammation-related cytokine. Although publications indicate that CRP is associated with the pathogenesis of neurological disorders and deemed to be a “risk factor” for Parkinson's disease (PD), the evidence exists still indefinitely. Here, we performed a systematic review with meta-analysis synthesizing all the eligible studies on serum, plasma, and cerebrospinal fluid (CSF) CRP levels and PD risk to investigate the potential relevance.Methods: A systematical search up to October 2018 was performed via PubMed, Embase, Science Direct, ISI Web of Science as well as three Chinese medical databases: China National Knowledge Infrastructure database (CNKI), VIP database and WanFang database. Risk was assessed by standardized mean difference (SMD) with 95% confidence interval (CI) to investigate the involvement of CRP levels in PD patients.Results: Twenty-three eligible case-control studies involving 4,598 individuals  were incorporated into this meta-analysis. Results have indicated significant increase of CRP levels in PD subjects when compared with control groups in serum , CSF  as well as whole blood .Conclusions: This meta-analysis revealed that PD is associated with an increase of CRP levels. CRP might be a risk factor for PD or PD leads to an inflammatory response. Parkinson's disease (PD) is one of the most complex neuro-degenerative disorders next to Alzheimer's disease. It is characterized by bradykinesia, tremor, rigidity, abnormal postural, and gait . PD has C-reactive protein (CRP), a kind of acute-phase protein and regulated by pro-inflammatory cytokines, is the most studied bio-marker of systemic inflammation . Some reThis meta-analysis was performed in line with the preferred reporting items for systematic reviews and meta-analyses (PRISMA) statement . A systeTwo investigators  independently identified and selected studies based on the Participants, Intervention, Comparison, Outcomes, and Study design (PICOS) framework . RegardiData was extracted from enrolled articles independently by two investigators . We collected the following data: (1) general information: first author, publication year, country of the population and study subjects; (2) patient characteristics: sample size, age, gender, clinical setting, adjusted variables for controls; (3) CRP assay type; (4) CRP level. Inconsistencies between the two authors were resolved by consulting a third reviewer (Wang J), and a level of 95% agreement was achieved. We contacted the investigators of the research for further information when required.Quality of each study was evaluated on the basis of the Newcastle-Ottawa Scale (NOS) . There wQ chi-square test and I2 metric. Substantial heterogeneity exists when I2 exceeding 50% and P-value < 0.5 for the Q test  was employed to perform this meta-analysis investigating the correlation of PD risk and CRP levels. Standardized mean difference (SMD) with 95% confidence interval (CI) for continuous outcomes was used to measure the differences of CRP levels between PD patients and healthy controls. The value of SMD < 0.2 implied a slight effect, indicating a low risk between CRP levels and PD, 0.5 indicated a moderate effect, and exceeding 0.8 suggested a significant effect . Heteroge Q test . A randoe Q test . Subgroue Q test . P-valueA flowchart describing the study selection process is displayed in The descriptive data of the 23 studies are outlined in P < 0.001) .Twenty studies –35, 37 m< 0.001) , a randoI2 = 96.5%). Sensitivity analysis was conducted to address the potential heterogeneity on account of the impact of enrolled studies on the overall effect size and its quality (P < 0.001) also provided statistical evidence of publication bias.Subgroup analyses were conducted according to CRP measurement manner. Results suggested that CRP levels were significantly increased in studies using hs-CRP as a measurement method , a random-effect model was employed (P = 0.01) found the exist of publication bias.Twelve studies –34, 37 iemployed , 45. BecP < 0.001, I2 = 95.2%, P < 0.001) were observed, a random-effect model was utilized. We did not perform further subgroup analysis considering the limited number of included studies.CRP levels in CSF were analyzed in 491 participants from four studies , 36, 38.P < 0.001) did detect the occurrence of publication bias because of the four studies . Some studies , 35 measIn present, the mechanisms of elevated CRP levels and neuroinflammation underlying the pathophysiology of PD are still not completely elucidated. As a neurodegenerative disorder, PD is associated with progressive dopaminergic neuronal degeneration in the substantia nigra. And its prominent neuropathological feature is the presence of Lewy bodies predominantly composed of fibrillar α-synuclein . At the As we know, this is the most comprehensive meta-analysis of all the published studies that focused on the CRP levels in peripheral blood and CSF between PD patients and matched controls. Though a previous review conducted by Qin  assessedThere are still some limitations that should be carefully interpreted. Firstly, though we performed subgroup analyses to reduce the source of heterogeneity, there were remaining substantial heterogeneity, implying that some confounding variables might exit. Secondly, some studies were not included in this meta-analysis as they assessed the median absolute values of CRP in PD patients and healthy controls and data from these studies were unable to extract for analyses –56. ThirIn summary, the current systematic review reveals the CRP levels of blood and CSF were significantly elevated in PD patients when compared with healthy controls, indicating that CRP might be a risk factor for PD or PD leads to an inflammatory response.XQ and YX designed the study, reviewed the literature, conducted the statistical analysis and drafted of the manuscript collectively. JWu, LG, and YH performed summary tables, edited pictures, and discussed on the manuscript. JWa contributed significantly to the study design and critically revised the final manuscript.The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.


ICAM1 (intercellular adhesion molecule 1) gene on the genetic risk of multiple sclerosis. STATA 12.0 software was utilized to carry out the heterogeneity assessment, association test, and Begg’s test as well as the Egger’s tests and sensitivity analyses. A total of 11 high-quality case–control studies were selected from the initially retrieved 2209 articles. The lack of high heterogeneity led to the use of a fixed-effect model in all genetic models. The results of the association test showed a reduced risk of multiple sclerosis in the allelic G vs A  and dominant AG+GG vs AA  but not in other genetic models . In addition, the negative results were observed in further subgroup analyses based on ethnicity or Hardy-Weinberg equilibrium in all genetic models. Data from Begg’s and Egger’s tests further excluded the presence of remarkable publication bias, while sensitivity analysis data supported stable outcomes. Thus, we conclude that ICAM1 rs5498 may not be related to the risk of multiple sclerosis in Caucasian or Asian populations, which still merits further research.In the present study, we included currently published evidence to comprehensively evaluate the influence of the rs5498 polymorphism within the  HLA DRB1*15  within the major histocompatibility complex (MHC) was associated with the susceptibility to multiple sclerosis [IL7R (interleukin 7 receptor) rs6897932, IL2RA  rs2104286 and CD58 (cluster of differentiation 58) rs2300747 polymorphism, may be linked to the risk and progression of multiple sclerosis based on the data of large genome-wide association studies [ICAM1 (intercellular adhesion molecule 1) gene on the susceptibility to multiple sclerosis.Multiple sclerosis is a type of chronic degenerative disease in the central nervous system (CNS) with the features of inflammatory demyelination-induced relapses and progressive neurological disability ,2. Multiclerosis . A numbeThe ICAM-1 protein, which is also referred to as CD54 (cluster of differentiation 54), participates in a group of biological processes regarding the immune responses . As a meICAM1 gene on chromosome 19 [ICAM1 polymorphisms in some clinical diseases. For example, the ICAM1 rs5498 polymorphism was reported to be linked to a decreased risk of myocardial infarction (MI) [ICAM1 rs1799969 polymorphism may be associated with the occurrence of Bechet’s disease (BD), rheumatoid arthritis (RA) [ICAM1 rs5498 with the risk of multiple sclerosis; however, different conclusions were obtained. We therefore performed an updated meta-analysis for a comprehensive reassessment based on the available data.Several polymorphic variants, such as rs5498 A/G (Lys469Glu), rs1799969 G/A (Gly241Arg) and rs5491 A/T (Lys56Met), were reported within the osome 19 . Severalion (MI) . The ICAtis (RA) , and cantis (RA)  and 2003We designed and performed our meta-analysis prior to September 2018, following the preferred reporting items for systematic reviews and meta-analyses (PRISMA). The PRISMA-based analysis process was depicted in ICAM1 gene; and (d) allelic or genotype frequency data within cases and controls. Exclusion criteria: (a) review articles, meeting, meta, case report; (b) cell, mice, rat experiment data; (c) ICAM-1 expression data; and (d) data of non-SNP, non-multiple sclerosis or other genes.Adhering to the inclusion and exclusion criteria, we carefully screened the articles and finally evaluated the eligible case–control studies. Inclusion criteria: (a) case and control studies; (b) multiple sclerosis; (c) rs5498 polymorphism within the P value of Hardy–Weinberg equilibrium were collected and summarized in the tables. The study quality was appraised using the system of NOS .Of the eligible case–control studies, the first author, publication time, ethnicity, polymorphism, genotype frequency of control and case, control source, genotyping method, sample size, and I2-test and Q-statistical test to check the statistical heterogeneity of the studies. High heterogeneity (I2 > 50% or P < 0.05) led to the utilization of the DerSimonian and Laird method under the random-effect model, whereas the absence of remarkable heterogeneity (I2 < 50% or P > 0.05) led to the use of the Mantel–Haenszel method under a fixed-effect model.Statistical analysis was conducted with STATA 12.0 . Briefly, we performed the P value from the association tests under the allelic, homozygote, heterozygote, dominant, recessive, and carrier models, respectively. We performed the subgroup analyses based on the factors of ethnicity or Hardy–Weinberg equilibrium. We also used Begg’s test and Egger’s test to evaluate the potential publication bias. Sensitivity analysis with the sequential omission of each study was adopted as well to test the data stability.Additionally, we computed the OR (odds ratio), 95% CI , and After the computerized retrieval of databases, a total of 2209 articles  were obtained. We then discarded 634 duplicates and 1561 articles depending on the exclusion criteria shown in . AnotherPheterogeneity > 0.05 and I2 < 50%) led us to use the fixed-effect model for all genetic models. After pooling the different studies together, we observed a reduced risk of multiple sclerosis in the allelic G vs A  and dominant AG+GG vs AA  but not in other genetic models , thereby suggesting that ICAM1 rs5498 is not a strong susceptibility locus for multiple sclerosis in the whole population.As shown in Passociation > 0.05). Similarly, no significant association between ICAM1 rs5498 and multiple sclerosis was observed in subgroup analyses of studies with Asian populations or studies with PHWE > 0.05 under any of the genetic models (Passociation > 0.05). Forest plots of subgroup meta-analysis by ethnicity are shown in ICAM1 rs5498 may not be associated with the risk of multiple sclerosis in Caucasian or Asian populations.We also conducted a series of subgroup analyses based on the factors of ethnicity or Hardy–Weinberg equilibrium. As shown in PBegg > 0.05, PEgger > 0.05). Publication bias plots were presented in As shown in ICAM1 rs5498 polymorphism in the occurrence of multiple sclerosis. For example, the ‘G/G’ genotype of the ICAM1 rs5498 polymorphism was reportedly associated with a reduced risk of multiple sclerosis patients in Poland [ICAM1 rs5498 polymorphism was not related to the multiple sclerosis risk in Dutch [ICAM1 rs5498 frequencies between multiple sclerosis cases and negative control in the Slovak population [ICAM1 rs5498 polymorphism in the susceptibility to multiple sclerosis.During the systematic database searches, we evaluated the inconclusive or controversial results on the genetic influence of the n Poland  rather tn Poland . Additioin Dutch  or Iraniin Dutch ,26 populin Dutch . There ipulation . Howeverpulation . These dICAM1 rs5498 polymorphism in the risk of multiple sclerosis [ICAM1 rs5498 may be associated with an enhanced susceptibility to multiple sclerosis [ICAM1 rs5498 and multiple sclerosis risk was detected in other inheritance models  of the overall meta-analysis and in neither of the inheritance models used in subgroup analyses. Hence, our data failed to support a strong connection between ICAM1 rs5498 polymorphism and the susceptibility to multiple sclerosis, which is in line with the conclusion of prior pooling analysis [In 2000, Killestein, J. enrolled three case–control studies ,21,24 toclerosis . In 2003clerosis ,21,22,24clerosis . In the analysis .Several highlights exist in our study. First, population-based negative controls were utilized in all the eligible studies. Second, the results of Begg’s and Egger’s tests excluded the presence of large publication bias. Third, there is no evidence of high heterogeneity between studies in all meta-analyses. Fourth, stable results were detected in our sensitivity analyses. In addition, it is worth mentioning that, during the extraction of the genotype frequency data in the report by Luomala et al. in 1999 , we utilICAM1 rs5498 and multiple sclerosis risk was detected in the meta-analysis when only case–control studies with PHWE > 0.05 were enrolled. Third, of the eligible case–control studies, only allelic frequency data were extracted in one study [ICAM1 rs5498 polymorphism in the susceptibility to multiple sclerosis. Very limited data resulted in the failure of the relative meta-analysis concerning the combination of ICAM1 rs5498 and other potential functional variants, such as rs1799969 G/A polymorphism. Fifth, we should consider more adjusted factors  in the future, when more usable evidence is available.Nonetheless, we still need to note some disadvantages, which may affect our statistical power. First, as in other meta-analyses, small sample size was a factor in some comparisons. For instance, from 2209 articles, only eleven case–control studies were selected for statistical analysis, and only three case–control studies ,26 were ne study . Fourth,ICAM1 rs5498 polymorphism is not linked to the risk of multiple sclerosis in Caucasian and Asian populations. Given the limitations of our study, this negative conclusion still needs to be confirmed by more available evidence.In conclusion, we incorporated the current data for an updated pooling analysis, which indicated that the