Introduction: Published data regarding the association between solute carrier family 30, member 8 (SLC30A8) rs13266634 polymorphism and type 2 diabetes mellitus (T2DM) and impaired glucose regulation (IGR) risks in Chinese population are in-consistent. The purpose of this meta-analysis was to evaluate the association between SLC30A8 rs13266634 and T2DM/IGR in a Chinese population.Material and Methods: Three English  and three Chinese databases  were used for searching articles from January 2005 to January 2018. Odds ratio (OR) and 95% confidence interval (95%CI) were calculated with the random-effect model. Trial sequential analysis was also utilized.Results: Twenty-eight case-control studies with 25,912 cases and 26,975 controls were included for SLC30A8 and T2DM. Pooled risk allele C frequency for rs13266634 was 60.6% (95%CI: 59.2–62.0%) in the T2DM group and 54.8% (95%CI: 53.2–56.4%) in the control group which had estimated OR of 1.23 (95%CI: 1.17–1.28). Individuals who carried major homozygous CC and heterozygous CT genotype were at 1.51 and 1.23 times higher risk of T2DM, respectively, than those carrying minor homozygous TT. The most appropriate genetic analysis model was the co-dominant model based on comparison of OR1, OR2 and OR3. Five articles that involved 4,627 cases and 6,166 controls were included for SLC30A8 and IGR. However, no association was found between SLC30A8 rs13266634 and IGR . TSA revealed that the pooled sample sizes of T2DM exceeded the estimated required information size but not the IGR.Conclusion: The present meta-analysis demonstrated that SLC30A8 rs13266634 was a potential risk factor for T2DM, and more studies should be performed to confirm the association between rs13266634 polymorphism and IGR. Type 2 diabetes mellitus (T2DM) is an expanding global health problem . There aBefore type 2 diabetes occurs, glucose control is altered, which is reflected by higher fasting glucose and/or higher post-prandial glucose. This phenomenon is called impaired glucose regulation (IGR) and IGR is regarded as pre-diabetic state that includes impaired fasting glucose (IFG) and/or impaired glucose tolerance (IGT) . High glSLC30A8) is located on chromosome 8q24.11. It encodes ZnT-8, which is highly expressed in pancreatic islets and beta cells. ZnT-8 transports zinc from the cytoplasm into insulin secretary vesicles. Some studies have shown that the polymorphisms of SLC30A8 are associated with β-cell function and insulin release in vivo  to tryptophan (W) at position 325 (Arg325Trp). The association of rs13266634 polymorphism in IGR and T2DM has been demonstrated in different ethnic groups via GWAS , Wan Fang and CBMD databases for articles published prior to January 2018. The searching languages contained both English and Chinese, and only published studies were considered. The search strategy was based on combination of “SLC30A8 rs13266634 polymorphism and T2DM/IGR;  the association between 2DM/IGR;  and cleaThe following data elements from each study were extracted: name of first author, year of publication, region of the study population, ethnicity of Chinese population, source of control, genotype method, diagnostic criteria, risk allele  frequency, number of cases and controls, mean (or median) body mass index (BMI), percentage of men in cases and controls, and mean (or median) age. Data were independently extracted by two investigators who reached a consensus on all of the items. If there was a lack of genotype information, we contacted the corresponding author to obtain required data.The quality of studies was also independently assessed by two reviewers (DF and ZFF) based on a risk of bias assessment for genetic association study which was modified on the basis of both traditional epidemiologic considerations and genetic issues that were developed by Thakkinstian et al. , 18. TheP-value <0.05, it was considered to be disequilibrium. Both per-allele and per-genotype approaches were performed to estimate the effect of the rs13266634 polymorphism on the risk of T2DM or IGR.We used Stata 11.0  for all statistical analyses. The HWE was examined in control groups by Fisher's Exact Test. If the study was found not to be in HWE with Per-allele analysis: The risk allele C frequency for rs13266634 was estimated for each study by reported data, and the overall prevalence and 95% confidence interval (95%CI) were estimated. Odds ratios (ORs), as well as 95%CI, were also estimated.Per-genotype analysis: The genotype effect was also calculated if the genotype data could be extracted from the study. Three odds ratios were estimated: CC vs. TT (OR1), CT vs. TT (OR2), and CC vs. CT (OR3). If the main effect of the genotype was statistically significant, further comparisons of OR1, OR2 and OR3 were explored. These pairwise differences were used to indicate the most appropriate genetic model as follows: (1). If OR1 = OR3≠1 and OR2 = 1, a recessive model was suggested. (2). If OR1 = OR2 ≠ 1 and OR3 = 1, then a dominant model was suggested. (3). If OR2 = 1/OR3 ≠ 1 and OR1 = 1, then a complete overdominant model is suggested. (4). If OR1 > OR2 > 1 and OR1 > OR3 > 1 (or OR1 < OR2 < 1 and OR1 < OR3 < 1), a co-dominant model was suggested.Z-test was used to determine the statistical significance of the pooled OR, and its P-value was used to determine if the overall SNP effect was significant (α = 0.05). The Q test based on a Chi-square analysis was used to assess the existence of heterogeneity. p = 0.01 was selected as the boundary value of the judgment to minimize type 2 errors   in a meta-regression if these data were available. A subgroup analysis was performed according to publication year, source of control, sample size, and quality scores.The estimation of the allele or genotype effect on T2DM was calculated by an OR and 95%CI. The 2 errors . The poo2 errors . The ran2 errors . In addigeneity) . A randoP < 0.05 was considered statistically significant in all analyses, except for the Egger test (p < 0.10) because of the low power of the test.A sensitive analysis with a single study being removed each time was performed to reflect the influence of the individual data set on the pooled OR. Publication bias was evaluated using Egger's linear regression asymmetry test and visual inspection of funnel plots, and the influence of potential publication bias on results was explored by using the Duval and Tweedie trim-and-fill procedure , 24. P <Meta-analyses might result in type-I errors owing to an increased risk of random error when fewer patients are involved, and due to continuous significance testing when a cumulative meta-analysis is updated with new studies , 26. TheA total of 381 articles were retrieved by literature search Figure –31; fourI2 = 88.8%, p < 0.001) and 54.8% (95%CI: 53.2–56.4%) in the control group . The odds ratio (C vs. T) was largely heterogenous  with a pooled odds ratio of 1.23 (95%CI: 1.17–1.28), and the overall SNP effect estimated by the random effect model was significant  in the T2DM group with high heterogeneity (p < 0.001) with large between-study heterogeneity (I2 = 53.9%) for CC vs. TT, 1.23  with small heterogeneity (I2 = 19.4%) for CT vs. TT, and 1.19  with small heterogeneity (I2 = 12.2%) for CC vs. CT, which suggests a co-dominant model (CC vs. CT vs. TT) for the putative susceptibility allele C with T2DM , for CC vs. TT , and for CC vs. CT , and the funnel plots for all comparisons were asymmetric. However, after imputing 6, 6, 4, and 1 missing studies for C vs. T, CC vs. TT, CC vs. TT, and CC vs. TT, respectively, by using the trim-and-fill method, the recalculated pooled ORs were not substantially different from the initial  in IGR group, and it was 54.0%  in the control group. The pooled OR of C vs. T was 1.13  with significant between-study heterogeneity  suggested that there was no publication bias.The pooled frequency of the major C allele was estimated to be 57.2% (95%CI: 55.8–58.7%) with moderate heterogeneity . It should be noted that this result was not consistent with the study in Europeans  in the ZnT8 molecule , and the estimation of genotype effects on T2DM may not be strong enough. Thus, a more precise association should be explored with sufficient data. These results should be interpreted with caution until further verification of sequencing approaches and larger meta-analysis are performed. Finally, significant publication bias was observed for all comparisons for T2DM. However, after imputing missing studies by using the trim-and-fill method, the recalculated pooled ORs were not substantially changed.SLC30A8 gene was associated with T2DM risk in the Chinese population. More studies are needed to confirm the association between rs13266634 polymorphism and IGR risk. The current evidence is insufficient to inform clinical decision making or policies until better understanding of the full functional implications is obtained. In addition, comprehensive analyses of gene-gene and gene-environment interactions should also be evaluated in the future.The present meta-analysis indicated that the rs13266634 C allele in the CJ, GY, and FZ designed the study. FD and BZ extracted the data. SZ, XH, XD, and KZ performed the analyses. FD and FZ wrote the draft. CJ, GY, FZ, XC, JW, DL, ZW, XZ, YL, and SD revised it.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.


IL10 polymorphisms − 1082 A > G (rs1800896), -819C > T (rs1800871), − 592 A > C (rs1800872) and the risk of either chronic periodontitis or aggressive periodontitis.Periodontitis is a major oral health problem and it is considered as one of the reasons for tooth loss in developing and developed nations. The objective of the current review was to investigate the association between IL10 polymorphisms  and the risk of periodontitis. For pooling of the estimates across studies included, the summary OR and its 95% CIs were calculated with random-effects model. The pooled estimates were done under four genetic models such as the allelic contrast model, the recessive model, the dominant model and the additive model. Trial sequential analysis (TSA) was done for estimation of the required information size for this meta-analysis study.This is a meta- analysis study, following the preferred reporting items for systematic reviews and meta- analyses (PRISMA). Relevant studies were searched in the health related electronic databases. Methodological quality of the included studies were assessed using the Newcastle-Ottawa Scale. For individual studies, odds ratio (OR) and its 95%confidence interval (CI) were calculated to assess the strength of association between IL10–1082 A > G polymorphism and the risk of chronic periodontitis in the non-Asian populations was observed only in the recessive model . The significant associations between − 592 A > C polymorphism and the risk of aggressive periodontitis in the non-Asian populations were observed in particular genetic models such as allele contrast  and recessive models . The TSA plot revealed that the required information size for evidence of effect was sufficient to draw a conclusion.Sixteen studies were identified for this review. The included studies were assessed to be of moderate to good methodological quality. A significant association between polymorphism of IL10–1082 A > G polymorphism was associated with chronic periodontitis CP risk in non-Asians. Thus, in order to further establish the associations between IL10  in Asian populations, future studies should include larger sample sizes with multi-ethnic groups.This meta-analysis suggested that the The online version of this article (10.1186/s12903-018-0637-9) contains supplementary material, which is available to authorized users. Periodontitis is defined as an inflammatory disease of supporting tissues of teeth caused by specific microorganisms or groups of specific microorganisms, resulting in progressive destruction of the periodontal ligament and alveolar bone with periodontal pocket formation, gingival recession or both . There aWorldwide, the prevalence of CP in the general adult population was reported to be 30–35%, with approximately 10–15% diagnosed with severe CP . AccordiIL)10 is an immunoregulatory cytokine and down-regulates the Th1 driven pro-inflammatory response [IL10 is associated with an enhanced immunopathological response to infection as well as an increased risk for the development of many autoimmune diseases [IL10 and the risk of developing periodontitis. These individual studies, however, showed conflicting results. Such inconsistency of the results may be attributed to small sample size, insufficient statistical power and ethnic diversity of the population. Taken together, the objective of the current review was to investigate the association between polymorphisms of IL10–1082 A > G (rs1800896), -819C > T (rs1800871), − 592 A > C(rs1800872) and the risk of either CP or AP.Although the presence of microorganisms is crucial for the clinical status, host response to bacteria triggers the secretion of pro-inflammatory mediators, leading to extra cellular matrix metabolism and bone resorption in periodontitis , 7. Interesponse . It is presponse . Studiesdiseases . Althougdiseases , 13. TheThe current study followed the preferred reporting items for systematic reviews and meta- analyses (PRISMA)  Additio.Relevant studies were searched in the health-related electronic databases of PubMed, EMBASE, web of science and google scholar, with the combination of the keywords with Boolean operators: “periodontitis” OR “chronic periodontitis” OR “aggressive periodontitis” AND “interleukin-10” OR “IL10” OR “-1082 A/G”. OR “-819 C > T” OR “-592 A > C”.The search was limited to the studies published in English and Chinese (abstract in English) from 1968 until March 2018. The references of retrieved articles and relevant reviews were checked for any additional studies.i)IL10–1082 A > G (rs1800896), 592 A > C (rs1800872) and/or − 819 C > T (rs1800871) were investigated.ii)it was case-control or nested case-control design.iii)periodontally healthy controls were included.iv)genotype distribution in both cases and controls were available.Human studies of any sample size that assessed periodontitis were included, if:CP and AP in the current analysis were as defined in the primary studies. Studies, which did not meet the inclusion criteria were excluded. Studies based on family or sibling-pairs were also excluded.Three investigators  individually checked the titles and abstracts, and then selected the relevant full-text articles, according to the inclusion criteria. The three investigators independently extracted data, using a piloted data extraction form. The following information were collected from each study: author, publication year, country, design , the number of cases and controls, the racial descent (Asian or non-Asian), clinical types of periodontitis, genotyping method and genotype/allele distribution in both cases and controls. Any discrepancy was resolved by discussion and consensus. If allele frequency was zero, then a value of 1 was added to all allele, following Laplace approximation .The two investigators  independently assessed the methodological quality of studies, using the Newcastle-Ottawa Scale (NOS) for quality assessment , with nep > 0.05 was regarded as consistent with HWE [IL10  and the risk of periodontitis (CP or AP) was estimated using odds ratio (OR) and its 95% confidence interval (CIs). Heterogeneity was statistically assessed using the I2 test. The I2 test values describes the percentage of total variation across studies that is attributable to the heterogeneity rather than chance. I2 values greater than 50% is considered as substantial heterogeneity [Hardy-Weinberg Equilibrium (HWE) in the controls was tested, using the exact test for goodness-of-fit and with HWE . The strogeneity . For pooogeneity , 21.Trial sequential analysis (TSA), an approach that adjust for random error risk, was done for estimation of the required information size . It is cmeta package (metabin command) in R 3.4.3 software (The R Foundation). TSA was done with TSA version 0.9 beta .Meta-analysis was done with RevMan 5.3  and Leave-one-out meta-analysis was with Figure The main characteristics of the studies identified for this review are presented in Additional file IL10–1082 A > G polymorphism and the risk of AP in a subgroup of the non-Asian population under the recessive model    and the recessive model  showed significant relationship between this SNP and the risk of AP  polymorphisms. An example illustration with IL10–1082 A > G under dominant model is shown in Additional file To assess the influence of individual data on the pooled ORs, leave-one-out meta-analysis was performed. The overall estimate of recessive model of udy Fig. . This inudy Fig. . This imIL10–1082 A > G in CP that followed HWE. We used an overall 5% risk of a type I error and 20% risk of a type II error (power of 80%). The cumulative z-curve crossed the traditional boundary and the trial sequential monitoring boundary and reached the required information size, suggesting there is no need for more evidence to establish additional study of − 1082 A > G in CP among the non-Asian population  and the risk of CP/AP, and the major observations are as follows;i.A significant association between − 1082 A > G polymorphism and the risk of CP in the non-Asian populations was observed only in the recessive model.ii.In subgroups with ethnicity, the significant associations between − 592 C > A polymorphism and the risk of AP in the non-Asian populations were observed in particular genetic models such as allele contrast and recessive models.iii.The TSA plot revealed that the required information size for evidence of effect was sufficient to draw a firm conclusion.The current study provides evidence on the association between - cytokine and TNF-a- cytokine [The numbers of inflammatory leucocytes that express the anti-inflammatory IL10- cytokine are much more widely distributed than those that express the pro-inflammatory IL6cytokine . The poocytokine . The laccytokine . Anothercytokine . In subsA significant association between − 592 A > C polymorphism and the risk of AP in allele contrast and recessive model indicated the prominent role of AA in the risk development. Although environmental factors are considered to be important in the establishment of periodontitis, individuals reared or living in similar environments may manifest significantly different disease patterns . The poo. Smoking habit represents an additional factor involved in periodontal disease progression that could mask the effects of IL10 SNPs on periodontitis outcome [IL10  and other genes (gen-gen interaction/synergism).The reason why different association was observed in different SNPs remained unclear. One possible explanation is the differences in the frequencies of the polymorphisms among diverse ethnicity, which may partly give rise to heterogeneity. Moreover, the complex nature of the disease, which is the result of an interplay between immunological, microbiological and environmental factors, may be the reason for that no difference . Smoking outcome . AdditioIt is postulated that polymorphisms in genes that codify mediators involved in the upstream positions of inflammatory-immune response pathways (such as IL-10 cytokine), which modulate a broad range of factors, may be relevant to periodontitis outcome , 57.Genotypic differences in cytokine genes are differently inherited to ethnically different populations . IndividOn the other side, polymorphisms in downstream genes , whose products present a narrow action in the pathways involved in periodontal tissue destruction, would play a minor role (or even do not play a significant role) in the development of periodontal diseases . For theIL10  and other genes (gen-gen interaction/synergism). Hence, findings in the current meta-analysis should be interpreted with caution.There are some limitations in the present study. Only two studies included in this meta-analysis (11.7%) were from the Asia population. A small sample size in the Asian population subgroup analyses may not be the representative of the population. Hence, a selection bias with geographical imbalance is a concern. Our analysis was done with the unadjusted raw data provided in the primary studies, in which patients might have some common factors . An earlier meta-analysis had highlighted that the inclusion of both smoking and non-smoking subjects in the primary studies can be an additional source of variability . StratifIL10 gene polymorphisms with periodontitis susceptibility may promote our understanding of its pathogenesis and explain individual differences in the risk.Interventions with the manipulation of anti-inflammatory cytokines have been suggested as adjuvants for treating periodontal disease. The efficacy of anti-cytokine biotherapies in patients with inflammatory diseases is a proof that blocking the effects of a cytokine can slow down the disease process . InvestiIL10–1082 A > G polymorphism was associated with CP risk in non- Asians. To further establish the associations between IL10 , future studies with larger sample sizes and multi-ethnic sample groups more with Asian population are required.Findings suggest that the Additional file 1:PRISMA Checklist. (DOC 60 kb)Additional file 2:Characteristics of the included studies. (DOC 78 kb)Additional file 3:The excluded studies. (DOC 34 kb)Additional file 4:The methodological quality of studies. (DOC 45 kb)Additional file 5:Summary of the pooled estimates for the three polymorphisms. (DOC 103 kb)Additional file 6:IL10–1082 A > G in the recessive model. (PDF 105 kb)Subgroup analysis of the studies on Additional file 7:IL10–1082 A > G in the recessive model. (PDF 84 kb)Funnel plot of studies on Additional file 8:IL10–1082 A > G in chronic periodontitis. (PDF 211 kb)Trial sequential analysis of studies on


There are limited data on the role of nutrient patterns in development of polycystic ovary syndrome (PCOS). The aim of the study is to document the relationship between nutrient patterns and PCOS.In this study, 281 incident PCOS women and 472 controls were interviewed through the endocrine clinics between February 2013 and March 2015 in Tehran, Iran. Usual dietary intakes were obtained using a validated semi-quantitative food frequency questionnaire. Factor analysis was conducted on the basis of 32 nutrients. Unconditional logistic regression was performed to ascertain odds ratios. The p<0.05 was considered for significance level.In principal component analysis two nutrient patterns emerged. Factor 1 had high loadings for riboflavin, niacin, pyridoxine, thiamin, magnesium, pantothenic acid, cobalamin, vitamin C, folate, vitamin D, total fiber, selenium, phosphorus, vitamin E, manganese, vitamin K, monounsaturated fatty acids, polyunsaturated fatty acids, potassium and vegetable protein. Factor 2 characterized by high loadings for carbohydrate, animal protein, fat, cholesterol, saturated fatty acid, sodium, biotin, copper, iron, fluoride, zinc, and calcium. After adjusting for potential confounders, the risk of PCOS was significantly higher in the highest tertile of factor 2 . Conversely, being in the highest tertile of factor 1 was associated with a lower risk of PCOS .Our results provide a possible new insight into the interactions between nutrient intakes and PCOS. Polycystic ovary syndrome (PCOS) is one of the most commonly encountered endocrinopathy in women of reproductive age, with metabolic and reproductive consequences, including anovulation, infertility and increased risk of type 2 diabetes mellitus, hypertension, impaired glucose tolerance (IGT), coronary artery disease, endometrial and perhaps breast cancer –3, with Existing epidemiological studies have illustrated a link between PCOS and lifestyle patterns –7. A posAlthough nutrition has consistently been found to be an important determinant of the PCOS risk, only few studies have evaluated the effect of isolated nutrients on PCOS characteristics , 12–15, In this case control study, the consecutive incident PCOS cases (n=288) and healthy controls (n=491), aged 20–35 years, were recruited between February 2012 and March 2014 from the endocrinology clinics of hospitals, Tehran, Iran.Newly diagnosed PCOS cases (identified within 3 month of diagnose) were diagnosed by at least two of the three symptoms according to the international Rotterdam Criteria 2003 . CriteriUsing pre-structured pre-tested questionnaires, informed and consenting patients in case and control groups were interviewed face-to-face by trained professional interviewers. Socio-demographic information on age, age at menarche, familial history of PCOS, smoking status, education, history of medication and supplement use and monthly family income was obtained from responses to the pretested baseline questionnaire. Consumption of alcohol and opium was not responded in the present study due to subjects’ cultural and religious believes.cm. Weight was then divided by the square root of height for calculation of body mass index (BMI). Waist circumference (WC) was measured at the umbilical site using an outstretched tape meter and without pressure to body surfaces, and was recorded to the nearest 0.1 cm. All measurements were carried out by one examiner to avoid random observer error.Weight was measured while participants were minimally clothed and standing on digital scales  without shoes and was recorded to the nearest 100 grams. Height was measured in a standing position without shoes while the shoulders were in a normal state using a non-stretch tape meter fixed to a wall and was recorded to the nearest 0.5 hr for an activity was calculated. Crude MET hr/day was then calculated adding the MET hr values for different activities in a day.Physical activity was measured through interviews using a previously validated questionnaire , 19. ThiTrained dietitians collected dietary data using a validated semi-quantitative food frequency questionnaire (FFQ) which assessed dietary intakes of cases one year before diagnosis and controls one year before. The validated FFQ consisted of 168 food items, including some of the most common Iranian meals . The detTotally, seven cases and eleven controls were excluded from the analysis since their log scales of total energy intake was either >3 or <3 SD from the mean, indicating under/over-reporting. After excluding the under- and over reporters of energy, 281 PCOS cases and 472 controls were included in the analyses. Participation rates were 97.5% and 96.3% among cases and controls, respectively.In the present study, “principal components method for factor analysis” of the SPSS  statistical analysis soft-ware version 20 was employed to derive potential nutrient patterns on the basis of 32 nutrients . The corUsing the correlation matrix, the orthogonal varimax rotation method was applied to achieve a simpler structure facilitating interpretation. The number of meaningful components to retain from the total number of extracted patterns depended mainly on the assessment of scree plots and components’ interpretability. Factor score of each nutrient pattern was considered for each patient by summing the consumption of nutrients with weights that were proportional to their factor loadings. Factor loadings are correlation coefficients between nutrient and nutrient patterns; a positive loading in a factor shows a direct correlation with the factor, whereas a negative loading shows that the nutrient is inversely correlated with the factor. Scores for two nutrient patterns identified in this study (factor 1 and 2) were then divided into three categories based on the tertile.kg/m2), physical activity (MET hr/day), familial history of PCOS (yes/no) and total energy intake .Chi-square test was employed to evaluate the differences in distribution of categorical variables, and independent t-test was performed to check the differences in distribution of continuous variables. Unconditional logistic regression was performed to ascertain odds ratios (ORs) with 95% confidence interval (CI). The minimal adjusted model included age (4-year categories) and the full adjusted model included age (4-year categories), BMI  and had more energy intake , higher BMI  and higher WC . Cases had higher family history of PCOS (p<0.001). Sociodemographic data of participants across tertiles of healthy nutrient pattern is shown in The distribution of general characteristics of study participants among cases (n=281) and controls (n=472) has been shown previously . Compare2), niacin (Vitamin B3), pyridoxine (vitamin B6), thiamin (vitamin B1), magnesium, pantothenic acid (vitamin B5), cobalamin (vitamin B12), vitamin C, folate (vitamin B9), vitamin D, total fiber, selenium, phosphorus, vitamin E, manganese, vitamin K, monounsaturated fatty acids, polyunsaturated fatty acids, potassium, and vegetable protein. Factor 2 displayed high loadings for sodium, cholesterol, saturated fatty acid, fat, biotin, carbohydrate, iron, fluoride, zinc, copper, calcium and animal protein.Factor-loading matrix for the two retained factors is shown in To our knowledge, the present study, based on a valid and detailed FFQ, is the first case-control study to examine the relationship between nutrient pattern and PCOS risk. Our findings suggest that the first pattern  had a significant negative relationship with PCOS risk among a sample of Iranian women. In contrast, the second pattern  was positively associated with the risk of PCOS.There are few studies evaluating the relationship between dietary factors and PCOS risk, and all of them assessed the isolated dietary components –24. DougMost previous studies in PCOS patients have focused on the influence of an individual nutrient, whereas when an association with overall intake of a nutrient is observed, researchers may identify significant cumulative effects that may be too small to detect with isolated nutrients . The nutThe present study had several strengths; the most important of all is being the first study to assess the association of nutrient patterns with PCOS in a developing country. Studies in developing countries can provide unique opportunities to test the association between diet and disease . In addiMoreover, the participation rate in this study was high, which was another positive point. Subjects whose disease was diagnosed three months before the interview at the most were registered in the present study as incident cases in order to reduce the possibility of recall bias. This is due to the fact that dietary data collected at the time of disease ascertainment might not truly reflect past intakes or intakes during the disease development and cases might have changed their diets due to the disease symptoms (protopathic bias). Controls were also carefully selected from patients only with conditions not related to diet or other major risk factors of PCOS. Using the factor analysis is another strength point of this study because the nutrient patterns derived from factor analysis capture the effects of the combination of many interacting and synergic nutrients and represent a significant biological vision to focus on; this might result in stronger or more consistent results which could be applied to various populations more easily so that factor analysis has emerged as a method for comprehensive estimation of disease risk as compared to traditional analyses of isolated nutrients .Before the implications of our findings are considered, it is necessary to consider potential limitations and biases. First, several arbitrary but important decisions are involved in factor analysis approach, including the labeling of the components, the number of factors to extract, the method of rotation and even their interpretation . Second,In conclusion the first nutrient pattern showed an inverse association and the second nutrient pattern showed a direct association with PCOS among Iranian women. However, case-control studies may prove an association but they do not demonstrate causation. As a result, these findings need to be confirmed in future prospective studies for etiological purposes to draw more conclusive results.


The etiological nature of preeclampsia is heterogeneous. The use of biomarkers indices in early pregnancy helps to have appropriate stratification of pregnancies into high- and low risk for the purpose of choosing timely interventions.The aim of this systematic review was to determine the pathogenic role of soluble soluble fms-like tyrosine kinase-1 (sFlt-1) and placental growth factor (PlGF) in the prediction of preeclampsia in women.We performed a systematic search of the international databases including PubMed, Scopus, and Web of Science until August 2017. The quality of included studies was assessed using the Newcastle-Ottawa Scale. The primary outcome in this review was preeclampsia. The statistical heterogeneity was assessed using the XTotally, 284 records were identified in the initial search and 15 records were finally included in the meta-analysis. The pooled odds ratios (ORs) for the association between the high level of sFlt-1 and low level of PlGF and subsequent development of preeclampsia among women were 5.20 (95% CI: 1.24–9.16) and 2.53 (95% CI: 1.33–3.75), respectively. The mean difference for sFlt-1 and PlGF in women with preeclampsia compared to controls was 1.15 (95% CI: 0.43–1.86) and –0.94 (95% CI: –1.37–0.52), respectively. According to the results from this meta-analysis, increased levels of sFlt-1 and reduced levels of PlGF predict the subsequent development of preeclampsia. Preeclampsia is a multiorgan disease process characterized by hypertension and proteinuria. The severe preeclampsia happens with epigastric pain, headache, impaired vision, impaired liver function, thrombocytopenia, kidney dysfunction, red blood cell breakdown and low blood platelet count . Preeclampsia is associated with maternal and fetal adverse outcomes, and occurs in 2–8% of pregnancies. It is responsible for up to 15% of preterm births (3). Some risk factors may play a main role in the etiology of preeclampsia. These risk factors include diabetes mellitus, obesity, overweight, maternal age, nulliparity, high blood pressure, hypothyroidism, renal disease and family history of preeclampsia (4). The etiology for the pathogenesis of preeclampsia is yet to be fully known (5). Some studies proposed that placenta releases soluble angiogenic factors, which play a crucial role in endothelial dysfunction and development of preeclampsia-related symptoms before clinical manifestation of preeclampsia. The soluble fms-like tyrosine kinase-1 (sFlt-1) is one of these factors. It binds vascular endothelial growth factor (VEGF) A and placental growth factor (PlGF). They are the angiogenic main factors that are responsible for placental vascular development and function of mother endothelial (6). Different studies have shown that the rate of the two factors is more precise for diagnosing and prediction of preeclampsia than any of the factors alone. There is little data on sFlt1 or PlGF in pregnant women with major preeclampsia risk factors, and the majority have a small sample size. Too small a sample usually prevents the findings from being extrapolated, and significance relations may not be seen, however, the diagnose of preeclampsia based on the cut-off values of these two factors is still unknown and the results are inconsistent .To the best of our knowledge, no meta-analysis has been carried out regarding the effect of angiogenic factors on the risk of preeclampsia. Therefore, this meta-analysis was conducted for assessing the association between the angiogenic factors and the risk of preeclampsia.We performed a comprehensive systematic manual and electronic search to assess the pathogenic role of soluble sFlt-1 and PlGF in the prediction of preeclampsia. The PRISMA statement (8) was used to report this study . The relevant studies were systematically searched in international databases including Pub Med, Scopus, and Web of Science from database inception until August 2017.The search strategy was performed by the medical subject headings (MeSH) in the title, keywords, and abstracts  and were combined with Boolean Operators: AND and OR. After removing the duplicate articles, relevancies were checked by title and abstract review. Finally, to ensure the relevance of screened articles, their full text was reviewed. The cross-referring publication was done in order to increase the sensitivity of the initial search. There was no restriction applied on language and publication year. Among 284 selected articles in the initial search, 88 duplicate articles were removed; 159 articles rejected after reviewing abstracts, and 22 final articles remained for full-text evaluation, after these process 15 full-papers were finally selected for meta-analysis.Original researches (Case-controls and cohorts) which include these terms of examining both angiogenic factors in women with preeclampsia with two groups design, reporting of outcome information, also articles that reported the serum levels of sFlt-1 (pg per millilitre) and Free PlGF (pg per millilitre) were considered as inclusion criteria. Articles lacking reporting of the gestational age of participants and duplicate articles as well as animal studies were excluded also case reports, case series, comments, editorials, and reports were considered as exclusion criteria.The outcome definitions were as described in the definition of PE from the International Society for the study of Hypertension in Pregnancy (9). Two investigators  independently reviewed the full-text of articles to assess their eligibility in the meta-analysis. Any disagreement between the two was resolved by discussion within the team of authors.After review of all searched articles , irrelevant studies were excluded from the study. For the studies that were eligible for meta-analysis, the following information was extracted: publication year, first author, study population, trimester of pregnancy, total sFlt-1 (pg per milliliter), Free PlGF (pg per milliliter), number of subjects in each group, standard deviation, odds ratio (OR), their associated 95% confidence intervals (CI), and study design.Newcastle-Ottawa Scale (NOS) was used for quality assessment of the studies (10). The abstracting instrument included 8 items and 11 scores possible. Eventually, articles were classified to high quality  and Odds Ratio (OR)). The association of preeclampsia and angiogenic factors was reported by pooled OR. In addition, we used the MD to compare the serum level of angiogenic factors between women with preeclampsia and control group. The statistical heterogeneity among the results of included studies was investigated by X2 and quantified using IFigure 1 shows the results of the literature review and selection process. A total of 284 potentially relevant articles were identified from the initial literature review . After removing the duplicates, 196 articles remained, and then the authors excluded 159 articles by screening the titles and abstracts. After full-text examination 22 articles were excluded due to improper study design or missing data. Finally, 15 studies met the eligibility criteria for meta-analysis.Full characteristics of included studies are shown in table I. From 15 included studies, 14 studies had case-control design and one was a cohort study. All studies are published in English.The risk of preeclampsia in women with high level of sFlt-1 was reported in three articles . The OR of the risk of subsequent development of preeclampsia in women with levels higher than the cutoff value of sFlt-1 was 5.20 (95% CI: 1.24–9.16), which means that sFlt-1 increases 5.2 times the risk of preeclampsia in cases groups. The results of IThe risk of preeclampsia in women with low level of PlGF was reported in four articles . The OR of the risk of subsequent development of preeclampsia in women with levels lower than the cut-off value of PlGF was 2.53 (95% CI: 1.33–3.75), which means that PlGF increases 2.53 times the risk of preeclampsia in cases groups. The results of IMean of sFlt-1 in 14 studies was reported. The MD was significantly increased in intervention group 1.15 (95% CI: 0.43–1.86), which concluded higher level of sFlt-1 in women with preeclampsia. The results of IThe mean of PlGF was reported in 15 studies. The MD was significantly decreased in preeclampsia group –0.94 (95% CI:–1.37–0.52), which concluded lower level of PlGF in women with preeclampsia. The results of IIn this meta-analysis, patients with preeclampsia were classified as preterm . Therefore, we tried considering the most of published articles in this subject .This meta-analysis was conducted for the assessment of pathogenic roles of sFlt-1 and PlGF to predict the risk of preeclampsia in women. According to our knowledge, this is the first meta-analysis that assessed the association between angiogenic factors and preeclampsia, by best available evidence. In this meta-analysis, for careful attention, NOS tool was used for quality assessment. The abnormalities of numerous angiogenic factors are in relation with preeclampsia, but sFlt1 and the PlGF were most studied.et al. showed that low concentrations of PlGF during early gestation have a much greater risk of early-onset preeclampsia (21). Levine et al. showed that angiogenic imbalance is significantly to be greater in women who had early onset preeclampsia and also in pregnant women who delivered a small-for-gestational-age infant, the best explanations are defective angiogenesis in these cases (12).According to our results, increased levels of sFlt-1 predict the risk of preeclampsia in women. Also, reduced levels of PlGF had a significant role in preeclampsia in women. Therefore, an angiogenic imbalance in pregnant woman significantly related to preeclampsia. These findings are consistent with the results of previous reports that reported increasing concentrations of sFlt-1 increased the risk of preeclampsia in women , which occurred about five weeks before the incident of preeclampsia. The decreasing level of free PlGF and free VEGF that take place at the time of increase level of sFlt-1 to some extent may be attributable in part to the binding by sFlt-1. According to our findings, the MD of sFlt-1 was significantly increased in women with preeclampsia compared to the control groups; this rate is about 15%. Also, the MD of PlGF was significantly decreased in preeclampsia. Previous articles have reported that the decrease in the PlGF level beginning early in the second trimester is the main predictor for preeclampsia . Haggerty According to our findings, patients with a higher positive change in sFlt-1 and also patients with a low change in PlGF had a higher risk for the development of preterm preeclampsia. On the other hand, first- to second-trimester changes in angiogenic biomarkers are predictive of preterm preeclampsia.Currently, there is no widely accepted screening test for the prediction of preeclampsia in pregnant women. However, according to our findings, angiogenic factors can be considered as a screening tool for preeclampsia. Help in decision-making as well as the better decision in resource allocation are some other applications of our results.There are some limitations in this meta-analysis. Firstly, due to the different inclusion and/or exclusion criteria, the heterogeneity between the studies was high; therefore, the analysis of the source of heterogeneity was limited due to different sources. Secondly, articles that were reported effects size (OR) were limited, therefore final pooled analysis was limited to four articles. Thirdly, the design of all studies was retrospective cohort and mainly case-control study, therefore results were more prone to selection bias, and information on exposure is subject to observation bias in case-control studies. Finally, data that were provided by the studies included in the meta-analysis were not sufficient to perform some subgroup analyses based on confounding variables like gestational age and other clinical subgroups.In summary, our results show that the sFlt-1 concentration is five times higher in a woman with preeclampsia compared to the control groups, accompanied by a decrement in the circulating free PlGF levels. Therefore, our findings supported the results of previous reports regarding the important biologic role of angiogenic factors in preeclampsia.The authors declare that they have no conflict of interest.


Background: Accumulating evidence suggests that functional dysregulations of miRNAs, especially miR-196a-2 and miR-149, in cancers could be attributed to polymorphisms in miRNA sequences. This study was aimed at clarifying the association of mir-196a-2 rs11614913 and mir-149 rs2292832 with cancer risk by performing an updated meta-analysis of genetic association studies.Methods: PubMed, Embase, Scopus, and ScienceDirect databases were searched until 9 April 2018 to identify eligible studies. Studies should meet the following criteria to be included in the meta-analysis: evaluation of genetic association between rs11614913 and/or rs2292832 and susceptibility to cancer; A case-control design; Written in English; Availability of sufficient data for estimating odds ratio (OR) and its 95% confidence interval (95%CI). Studies that met the following criteria were excluded: review articles, meta-analysis, abstracts or conference papers; duplicate publications; studies on animals or cell-lines; studies without a case-control design; studies that did not report genotype frequencies. Pooled ORs and 95% CIs were estimated using a total of 111 studies  for mir-196a rs11614913 and 44 studies  for mir-149 rs2292832. Stratified analysis according to quality scores, genotyping method, ethnicity, broad cancer category and cancer type was also performed.Results: Mir-196a-2 rs11614913 T allele was associated with decreased cancer risk in overall population. The association was only significant in Asians but not Caucasians. In subgroup analysis, significant associations were found in high quality studies, gynecological cancers, ovarian, breast, and hepatocellular cancer. Mir-149 rs2292832 was not associated with cancer risk in overall population and there were no differences between Asians and Caucasians. However, the T allele was associated with a decrease risk of gastrointestinal tract cancers under the heterozygote model and an increased risk of colorectal cancer under the recessive model.Conclusions: The present meta-analysis suggests that mir-196a-2 rs11614913 may contribute to the risk of cancer especially in Asians. Mir-149 rs2292832 may modulate the risk of gastrointestinal tract cancers especially colorectal cancer. This study had some limitations such as significant heterogeneity in most contrasts, limited number of studies enrolling Africans or Caucasians ancestry and lack of adjustment for covariates and environmental interactions. MIR196A2, HGNC:31568) and mir-149  are well-studied miRNAs that may function either as oncomiRs, by targeting tumor suppressor genes, or as tumor suppressors, by targeting oncogenes, in different conditions  report, about one in six deaths were caused by cancer in 2015. It is predicted that cancer-related death will increase up to 13.2 million by 2030 worldwide  OR (“microRNA 149” OR “miRNA-149” OR “mir-149” OR “mir149” OR “pre-mir-149" OR “pre-mir149” OR “rs2292832”) AND (“single nucleotide polymorphism” OR “SNP” OR “variant” OR “variation” OR “polymorphism” OR “mutation” OR “locus”) AND . Last search was performed on 9 April 2018. References of the relevant literature and review articles were also evaluated to identify all potentially eligible articles. This meta-analysis carried out in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) statement  evaluation of genetic association between rs11614913 and/or rs2292832 and susceptibility to cancer; (2) a case-control design; (3) Written in English; (4) Availability of sufficient data for estimating odds ratio (OR) and its 95% confidence interval (95%CI). Studies that met the following criteria were excluded: (1) review articles, meta-analysis, abstracts or conference papers; (2) duplicate publications; (3) studies on animals or cell-lines; (4) studies without a case-control design (5) studies that did not report genotype frequencies.Data was extracted from each eligible study and manually checked. Then, items were recorded for each eligible study: the first author, publication year, category of cancer, type of cancer, country, ethnicity, source of controls, genotyping method, number of subjects in the case and the control groups, genotype counts for each SNP in the case and the control groups. A broad cancer category was assigned for each study according to the following scheme: gastrointestinal tract cancers , head and neck squamous cell carcinoma , gynecologic cancer , hematological malignancies , urogenital cancers , or other cancers.The quality of each study was assessed using quality assessment criteria for genetic association studies used elsewhere , the random effect (RE) model . In cases of remarkable heterogeneity , the potential sources of heterogeneity across studies was explored using univariate meta-regression and stratified analysis. Moreover, subgroup analyses based on genotyping method, study quality, ethnicities, broad cancer categories, and cancer types were carried out. To assess consistency of results and influence of each study on the pooled OR, sensitivity analysis was done by omitting one study at a time and recalculating summary OR and 95% CI. Publication bias was evaluated by the Begg's rank correlation test of funnel plot asymmetry .The Meta package for R was used to perform meta-analysis  may be caused by a range of factors, among which genotyping error is more importantly relevant to the association study context. Currently there is no consensus on the way of handling association studies with the controls not in HWE, but it has been recommended that such studies should not be excluded from meta-analysis  or an association study design (n: 5). Finally, a total of 127 eligible articles remained . With regard to the ethnicity, 85 studies were performed in Asians, 20 were performed in Caucasians and the remaining six studies were included either Africans or individuals from different ancestries (mixed ancestry). In four studies the patients were subgrouped into multiple cancer types. Namely, Liu evaluated both ovarian and endometrial cancers  evaluated the association of miR-196a-2 rs11614913 and cancer risk . The arters Liu, , Parlayaers Liu, , Toraih ers Liu,  and hepaers Liu, . For then: 39) were performed in Asian populations and only few studies (n: 5) had focused on Caucasians. According to the broad cancer category, there were 22 GI studies, seven HNC studies and 15 studies on other cancer types. When studies were subgrouped by cancer type, there were four studies on BC, nine studies on HCC, eight studies on GC, five studies on CRC, three studies on LC and 15 studies on other types of cancer.Moreover, 43 articles comprising 44 studies  evaluated the association of mir-149 rs2292832 and cancer risk , among wRE [95% CI]: 0.88 [0.79–0.98], P: 0.027) and the recessive  models , the recessive  and the allele contrasts . In subgroup analysis by genotyping method, the only significant association was observed under the recessive model for studies which used a method other than PCR-RFLP . When sub-grouped by ethnicity, decreased risks of cancer under the homozygote , the recessive  and the allelic  models were found only in Asians but not in Caucasians or the African/mixed ancestry subgroups  and the allelic contrast  , the recessive model  and the allele contrast , and with ovarian cancer . Statistically significant associations between mir-196a2 rs11614913 and cancer risk were observed assuming the homozygote  models . Mir-196) models . Supplemubgroups . Subgrou: 0.021) . No sign: 0.021) . Supplem: 0.021)  under thn cancer  under thRE [95% CI]: 0.75 [0.61–0.93], P: 0.011) and recessive  models . Furthermore, adjustment for HWD confirmed that mir-196a-2 rs11614913 is not associated with colorectal or lung cancer assuming any genetic model  revealed stable results in the overall analysis under the homozygote, heterozygote, dominant, and recessive models . However) models . The assic model .FE [95% CI]: 0.88 [0.79–0.98], P: 0.025). When subgrouped by broad cancer category, a decreased risk of gastrointestinal tract cancers was found in the heterozygote model . Subgrouping by cancer type, however, revealed an increased risk of colorectal cancer for individuals carrying TT genotype compared to those who carry at least one C allele . No significant association was observed for other comparisons  and with colorectal cancer risk under the recessive model . No association with breast cancer risk was identified after adjusting for HWD  and dominant  models could be attributed to the country moderator. However, there was still significant unaccounted heterogeneity even after correcting for the effect of country moderator . Moreover, Galbraith plot analysis demonstrated three studies , a 12.8% reduction in the heterozygote model (from 70.6 to 57.8%), a 12.3% reduction in the dominant model (from 76.9 to 64.6%), an 9.1% reduction in the recessive model (from 68.8 to 59.7%) and a 11.3% reduction in the allelic model (from 79 to 67.7%). However, excluding these studies did not alter any genotypic contrast and results were comparable to the overall analyses (data not shown). Sensitivity analysis by omitting one study at a time revealed that no individual study significantly influenced the genotype contrasts . Sensitivity analysis by omitting one study at a time revealed no single influential study (Statistically significant heterogeneity was also observed in the overall analysis of miR-149 rs2292832 and cancer risk and, consequently, RE model was used to estimate pooled OR . Subgroual study .Rank correlation test of the mir-196a-2 rs11614913 Begger's funnel plot asymmetry revealed no statistically significant evidence of publication bias in any contrast . HoweverThe possible contribution of miRNAs, especially mir-196a-2 and mir-149, to the risk of cancer has stimulated great attention in recent years. Many studies evaluated the functional alterations of these micro-regulators in a wide range of cancers. Accumulating evidence suggests that, at least a part of functional dysregulations of miRNAs in cancers could be attributed to polymorphisms in miRNA sequences (Hu et al., Increasing number of association studies evaluating miRNA polymorphisms and cancer risk with contradictory results merits the need for comprehensive systematic reviews and meta-analyses. Several meta-analyses have evaluated the risk of cancer associated with mir-196a-2 rs11614913 or mir-149 rs2292832 (Chu et al., For mir-196a-2 rs11614913, the previous largest meta-analysis, conducted by Liu et al. , includeThe current meta-analysis also showed that mir-149 rs2292832 is not associated with risk of cancer in any genetic model and the results were statistically reliable, as summary effects were not influenced by excluding any single study, HWE-deviated or low quality studies. No differences in cancer risk was observed between ethnicities. Similar to miR-196a-2 polymorphism, the Asian subgroup comprised a large proportion of studies and relatively few studies with limited sample sizes were performed in Caucasians. Therefore, a definite conclusion cannot be drawn in Caucasians and more studies are needed further clarify the association of this SNP with cancer risk in Caucasians. The results of overall analysis were comparable to previous meta-analyses (Li L. et al., However, the present study has some limitations. First, significant heterogeneity was present in most analyses especially for mir-196a-2 polymorphism. We, therefore, used random effect model and performed meta-regression; but no significant source of heterogeneity was observed for most analyses, suggesting that other unknown study level moderators may contribute to the heterogeneity. Second: The molecular mechanisms underlying association of these miRNAs-SNP with risk of cancer are complex and might be strongly affected by different genetic background as well as other masked variables. This, in turn, may limit the efficacy of the overall analysis especially in the case of miR-196a-2 rs11614913. Stratified analyses based on a specific cancer category or a cancer type may help to reduce this heterogeneity and, therefore, are considered to be more reliable. Third, this study was based on unadjusted ORs of the original studies and no adjustment for covariates like age and gender or interaction with environmental factors were done and this fact may also potentially contribute to the between study heterogeneity. Fourth, some limitations such as language restriction or lack of access to the genotype counts of mir-196a-2 rs11614913 in four studies with insufficiently reported data may bring in publication bias. The trim and fill method has been shown to reduce the bias in estimates in the presence of publication bias and heterogeneity (Peters et al., In conclusion, this meta-analysis showed that mir-196a-2 rs11614913 T allele is associated with decreased cancer risk in overall population, high quality studies and studies on Asian populations. It is also associated with a decreased risk of gynecological cancers, ovarian, breast and hepatocellular cancer. Mir-149 rs2292832 was not associated with cancer risk in overall population, high quality studies, Asians or Caucasians. However, the T allele was associated with a decrease risk of gastrointestinal tract cancers under the heterozygote model and an increased risk of colorectal cancer under the recessive model.MB and AM conceived the original idea and supervised the project. JC, ZN-S-F, and ZS contributed to the literature search and data management. MB, JC, and ZN-S-F wrote the manuscript with support from all authors. MB contributed to the data analysis, interpretation of results, and data visualization with inputs from AM. EO and ZS assisted with data visualization. All authors provided critical feedback, discussed the results, and contributed to 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.


The purpose of the present systematic review and meta-analysis was to evaluate and synthesize the currently available data on the correlation between rs12885713 and OA susceptibility.The single nucleotide polymorphism (SNP) CALM1 polymorphism and OA. Risk of bias was assessed through the Newcastle-Ottawa Scale. Predetermined subgroups and sensitivity analyses were performed using the RevMan 5.3 software. Publication bias was evaluated by Egger and Begg tests.Six electronic databases including PubMed, EMBASE, ISI Web of Science, CNETRAL, CNKI, and Wanfang were systematically retrieved to identify relevant observational articles published before October 2017. Summary odds ratios (ORs) and corresponding 95% confidence intervals (95% CIs) were calculated to indicate the association between rs12885713 SNP was not significantly associated with OA vulnerability . When stratified by different genders, OA sites, and population descents respectively, still non-significant associations were found.Overall, 5 case–control studies involving 2183 OA patients 2654 healthy control subjects satisfied the meta-analysis. Recessive model was confirmed to be the best-matching genetic model (TT + TC versus CC). The pooled outcomes indicated that rs12885713 polymorphism of CALM1 did not appear to be associated with OA predisposition.Based on the findings of our present study, the  It is reported that approximately 10% men and 13% women aged 60 and over suffer symptomatic knee OA. The incidence and prevalence of OA increase steeply with age, especially with the prolongation of human being lifespan over recent years. OA is increasingly becoming a serious public-health problem. Current epidemiological situation of OA has a noteworthy impact on society.Osteoarthritis (OA), mainly characterized by gradual damage of articular cartilage, synovial membrane, subchondral bone, ligament, joint capsule, and even the peri-articular muscles and tendons, is the most common type of arthritis and a leading cause of disability in elderly adults worldwide. Among them, genetic factors might play a pivotal role and have received high attention. A latest large-scale twin study across the UK has revealed a significant contribution of genetic factors with an estimated heritability of 37% to 65%. Other reports from Finland and America also highlighted the importance of OA heritability.,10 Taken together, these studies indicated the heritability of OA can be no less than 50%, suggesting that half the mutation in vulnerability to OA among population attribute to genetic factors. During the past 2 decades, considerable candidate genes with innumerous gene polymorphisms have been reported as concealing risk alleles for OA vulnerability. The candidates have been selected predominantly according to the principle that the product they code for is regulators of both joint formation and maintenance. A great many of polymorphisms in various genes such as ESR1,,13VDR,,15ADAM12,,17MMP3, and Asporin have been demonstrated to be related with risk of OA.The precise etiopathogenesis underlying OA remains unclear. Risk factors for OA include age, gender, abnormal loading, obesity as well as genetics.2+ receptor protein, regulates a range of signaling processes like cell proliferation and differentiation, cytoskeleton architecture and function, and metabolic homeostasis in eukaryotic cells. It is well-known that mechanical compression of articular chondrocytes can cause changes in Aggrecan gene expression, and relevant changes mainly rely on CaM signaling.,21 CaM is coded by 3 distinct CaM genes (CALMs), namely CALM1, CALM2, and CALM3.CALM2 has been reported to be associated with hip OA in Japanese population. Several studies also demonstrated the relationship between CALM1 and OA vulnerability with conflicting result.Calmodulin (CaM), a widely distributed CaCALM1 polymorphism and risk of OA using a meta-analysis approach.Most genes contributing to OA confer simply a very modest increase or decrease in the risk, and most of the gene-disease association studies used sample-sizes of hundreds but not thousands of cases and controls, they consequently lack the power to detect such associations. Compared to individual study, a meta-analysis can be conducted to enhance the statistical power of the association by enlarging the sample size and acquire a more accurate estimation. Therefore, we performed this study to investigate the association between 2 This systematic-review and meta-analysis do not need ethical approval because it does not include data linked to individual patient information.This systematic review and meta-analysis were conducted following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines.2.1calmodulin or CALM1) and (OA or osteoarthrosis or osteoarthritides or “Osteoarthritis”[MeSH]). For Chinese academic databanks, we used “duo tai xing” together with “CALM1” to identify related Chinese articles. The bibliographic lists of relevant reviews and full-text articles were also manually searched to capture additional possible studies.The literature search of this study was conducted on 6 online electronic databases including PubMed, EMBASE, ISI Web of Science, CNETRAL, CNKI, and Wanfang, with all articles published previous to October 2017. A combination of Medical Subject Headings (MeSH) together with free terms and was used to retrieve all the potentially eligible publications. No language restrictions were imposed. The following search strategy was used in English databases:  and (2.2Studies meeting the following criteria were included for review:(1)rs12885713 polymorphism in CALM1 and OA susceptibility that have been published;studies that assessed the correlation between the (2)studies should be designed based on a case-control design;(3)the diagnosis of OA should be made according to well-established diagnostic criteria and confirmed by radiographic images, subjects in control groups should be without any history or sign of OA;(4)studies were required to provide sufficient data to calculate the odds ratio (OR) with its 95% confidence interval (95% CI).Correspondingly, studies satisfying the following criteria were excluded:(1)animal studies, review, expert opinion, conference abstract, case report, or case series;(2)data that overlapped with previous publications;(3)studies failed to provide sufficient data to evaluate OR and the associated 95% CI.2.3 Three broad perspectives including selection of cases and controls, comparability of the groups and ascertainment of outcome of interest were evaluated using the Star system. Discrepancies between reviewers were settled through discussion until a mutual consensus was reached.The methodological quality of eligible studies was assessed independently by 2 reviewers (J. Shi and S. Gao) using the Newcastle-Ottawa Scale (NOS) for observational studies.2.4Two investigators (J. Shi and S. Gao) conducted the reading and data extraction of all the included studies independently. A standardized data extraction list was utilized to collect information including first author, year of the publication, country, ethnicity of enrolled subjects, diagnosis of cases, genotypes distribution of cases and controls, Hardy–Weinberg Equilibrium (HWE) for control subjects in each study. In the event of any discrepancy through the process, 2 reviewers reinvestigated the article together and discussed with each other until coming to an agreement.2.5rs12885713 polymorphism in CALM1 and risk of OA was indicated as OR along with the associated 95% CI. In order to avoid an inflated Type I error rate, we did not perform any assumptions about the genetic model of inherence in advance. The most appropriate genetic model for CALM1 polymorphism in the risk of OA was determined by a model-free approach. Briefly, OR1, OR2, and OR3 were calculated for genotypes TT versus CC, TC versus CC, and TT versus TC to capture the magnitude of genetic effect. Then the most plausible genetic model of inherence was determined according to the relationships between the 3 pairwise comparisons as follow:Departure from HWE was evaluated by using Chi-square test to assess goodness of fit in control subjects of each included study. The strength of association between (1)Recessive model: if OR1 = OR3≠1 and OR2 = 1;(2)Dominant model: if OR1 = OR2≠1 and OR3 = 1;(3)Complete over-dominant model: if OR1 = 1, OR2 = 1/OR3≠1;(4)Codominant model: if OR1 > OR2 > 1 and OR1 > OR3 > 1, or OR1 < OR2 < 1 and OR1 < OR3 < 1.2 test. The random-effect model and fixed-effect model were used for data combination in the presence  or absence of heterogeneity  respectively. In case of statistically significant heterogeneity across studies, subgroup-analysis by ethnicity, diagnosis, and gender were performed to find the possible source of heterogeneity.,29 The leave-one-out sensitivity analysis was conducted by removing each study in turn and reassessing the resulting effect on the overall effect. Power analysis was performed using the Power and Sample Size Calculation (PS) program (http://biostat.mc.vanderbilt.edu/wiki/Main/PowerSampleSize) to evaluate whether our meta-analysis could offer adequate power to detect the association between CALM1 polymorphism and risk of OA at a level of significance of 0.05. Egger regression test and Begg rank correlation test were used to estimate the publication bias . Forest plots and funnel plots were generated using RevMan 5.3 software .After that the underlying genetic model was confirmed, the counts of genotypes were collapsed into 2 categories to obtain the merged results. The between-study heterogeneity was assessed using the Q-statistical test and I33.1 was removed for irrelevance and 5 studies–35 were deemed eligible and included for meta-analysis. The process of literature search was presented in Figure Six online databases were searched for potentially relevant studies and the initial literature search yielded a total of 42 records including 13 from PubMed, 6 from EMBASE, 19 from ISI Web of Science, 2 from Wanfang and 2 from CNKI. After the integration of these records, 15 duplicated records were removed and the remaining 27 were screened for titles and abstracts for eligibility. According to the predetermined inclusion and exclusion criteria, 21 irrelevant studies were excluded and the remaining 6 studies were subject to a full-text screen. Finally, 1 study 3.2 India, Greece, China,  and Japan, respectively, the sample-size ranged from 351 to 1672. Three of 5 included studies–33 focused on the association between rs12885713 and KOA while the remaining 2 studies,35 featured to assess the association in HOA. The clinical stage of OA was assessed by radiographic images according to the Kellgren–Lawrence classification system. The genotype frequencies of case and control groups were summarized in Table The main characteristics of included studies were presented in Table According to the NOS, our included studies achieved an average of 5.6 stars for methodological quality assessment Table .3.3P = .001) and OR3  were both statistically significant whereas the estimated OR2  was insignificant, suggesting that the recessive model was the most plausible genetic model for meta-analysis. When using the recessive model, the counts of genotypes of TT and TC groups were combined and compared with CC groups. Since there was no heterogeneity among included studies , the fixed-effect model was used for statistical analysis. The combined ORs showed that there was no statistically significant association between rs12885713 in CALM1 and risk of OA  , gender  and diagnosis (HOA and KOA) to evaluate the association between 3.4rs12885713 polymorphism and risk of OA remained insignificant after the removal of any included study (detailed data not shown). The funnel plot was symmetrical  and Begg test  also suggested no statistically significant publication bias. The result of power analysis suggested that our meta-analysis had a power of 1.00 to detect the association between CALM1 polymorphism and risk of OA at a level of significance of 0.05.The leave-one-out sensitivity analysis confirmed the robustness and reliability of our drawn conclusion. The association between 4rs12885713 polymorphism in CALM1 was not statistically associated with risk of OA, regardless of the OA diagnosis, gender or ethnicity.Despite the etiopathogenesis of OA is multifactorial and largely undetermined, both intrinsic factors and extrinsic factors are considered to be etiology. To some extent, epidemiological studies have encouraged us to quantify the contribution of those individually independent risk factors to OA. Owing to the predominant effect of genetic factors on OA, a better understanding of gene polymorphisms correlated to OA liability enable us to predict the disease and take preventive measures, as well as identify potential targets for specific pharmacologic treatment. Based on the findings of our present study, CALM1 has been reported to contribute greatly to hip OA both in vivo and ex vivo studies. CALM1 is located at human chromosome 14q32.11. This gene along with CALM2 and CALM3 is responsible for the encoding of CaM, a type of highly conserved and ubiquitous Ca2+ binding protein controlling Ca2+-dependent processes in higher vertebrates. Valhmu and coworkers found that CaM involved in the metabolic activity in the bovine articular chondrocytes under mechanical stimulation. Mototani et al observed that CaM implicated in chondrogenesis through regulating the expression of COL2A1 and AGC1 genes whose expression products are type II collagen and aggrecan, both of which are principal component of extracellular matrix in cartilage. In addition, they also demonstrated the CALM1 expression level in human OA cartilage tissue was significantly higher than that in cultured normal human articular chondrocytes. Mishra et al reported that the reduced mRNA and protein expression level of CALM1 in the peripheral blood lymphocytes from OA patients appeared to be parallel to the decreased formation of cartilage as well as its disruption. These findings altogether suggested that CALM1 participated and played an important role in the OA pathogenesis.As an intrinsic genetic factor, the rs12885713 polymorphism and other gene variants cannot be denied. Under most circumstance, a gene functions through an intricate web of mechanisms, this rule also applies to gene polymorphisms. Just as Mishra et al have observed the distribution frequencies of the TGC haplotype that carries 3 variant alleles of T-rs12885713 and G-rs3814843 and C-rs2300496 among OA patients were significantly higher compared to the normal controls. Besides, when combining different polymorphic loci from ESR-a, CALM1, and GDF5, the variant genotype frequencies in OA patients were as well higher than the controls. What is more, Mototani et al and Poulou et al observed the combinatorial interplay between 2 loci from CALM1 and ASPN.,35Albeit a negative relationship in our study, the association between  initially reported the association between rs12885713 polymorphism of CALM1 core promoter and hip OA risk, another 4 comparable studies were also conducted among different ethnicities and population. However, subsequent replication studies performed in Caucasian, Chinese, and Indian populations failed to replicate positive results. These inconsistent results further emphasized the diversity and complexity of genetic impact on OA. To increase the statistical power, we collected the currently available evidence and conducted a comprehensive synthesis of these data. In the summarized analysis of 2183 OA patients 2654 healthy control subjects, our main findings indicated the rs12885713 polymorphism did not appear to be associated with OA risk under the best-matching recessive model. Considering genetic factors have been reported to function differently between the 2 genders, at distinct sites of the body, and among diverse population, we conducted subgroup analysis according to the corresponding differences. Nevertheless, there was still non-significant association could be detected, indicating that the rs12885713 polymorphism is not a likely liability locus for OA when examined in isolation.The most robust evidence for a veritable association between a specific gene and a certain disease ought to derive from well-designed studies with large sample. Only such evidence is able to withstand the confirmation of later replication studies. By a large-scale association study accompanied with the subsequent functional investigations, Mototani et alCALM1 polymorphism and risk of OA remained insignificant under the most plausible genetic model, the results were strengthened by no statistical between-study heterogeneity (I2 = 0%) and validated by the leave-one-out sensitivity analysis. The initial study of association between CALM1 and risk of OA may have been a false-positive result due to chance or systemic bias existed in the corresponding study. According to the methodological quality assessed using NOS, Mototanis’ study achieved 5 stars, while the investigators failed to report the controlling for important factors, the representativeness of cases in the study was also insufficient. Additional association studies and further functional studies are warranted to confirm the real association between CALM1 polymorphism and risk of OA.For the most part, most genes contributing to a certain disease confer only a very modest increase or decrease in risk of disease. Thus, to detect these gene-disease associations with adequate statistical power requires large sample size. To avoid yielding an inflated Type I error by using multiple genetic models of inheritance, we adopted a model-free approach without assuming a genetic model in advance. The association between CALM1 polymorphism and risk of OA, especially when the overall effect is marginal. Second, only 5 studies were included in our meta-analysis, the number of included studies was relatively small. Third, 4 of the 5 included studies were hospital-based, thus it was difficult to avoid the overestimate of OR caused by high selection of participants. Fourth, 2 factors were considered to contribute to the null association of our present study. On the 1 hand, perhaps the comparatively limited sample size of our study was not powerful enough to obtain a significant association; on the other hand, of these included studies, participants did not share the same ethnic origin, age was variable, OA site was different as well. Such clinical heterogeneity might also conceal the actual association. If rs12885713 contributes predominantly to a specific subtype of OA such as KOA and HOA, then the pooled results from different studies will possibly affect the power of each study to detect the real association. Population heterogeneity across included studies could result in differences in study outcomes as well. In the subgroup-analysis by ethnicity, Asian included Chinese, Japanese and Indian. Although a previous meta-analysis of replicated genetic association studies reported that even when the SNP frequency differs across populations, the overall effect of mutations remains approximately constant, the negative findings of our current meta-analysis should be interpreted with caution. However, although some limitations existed in our present study, the overall methodological quality of included studies was moderate and the data from each individual study were consistent. A reasonable degree of confidence should be given to the null association between CALM1 polymorphism and risk of OA based upon the results of our meta-analysis. Additional association studies with larger sample size within other ethnicity backgrounds are strongly encouraged.Several limitations in this study should not be neglected when interpreting the results. First, all included studies used sample of hundreds but not thousands of cases and controls, they may lack the ability to detect the association between Hao Kang produced the idea to this study and he was responsible for making the final version of this paper. Jia Shi, Shu-tao Gao, and Zheng-tao Lv did the literature search, screened the potentially eligible studies and evaluated the data from each included study, they contributed equally to this work. Wei-bin Sheng critically revised this manuscript, including important intellectual contents and the grammatical mistakes existed in our original study. Hao Kang had full access to all of the data in the study and takes responsibility for the integrity of the data and the accuracy of the data analysis.Conceptualization: Hao Kang.Data curation: Jia Shi, Shu-tao Gao, Zheng-tao Lv, Hao Kang.Formal analysis: Jia Shi, Shu-tao Gao, Zheng-tao Lv.Funding acquisition: Hao Kang.Investigation: Jia Shi, Shu-tao Gao, Zheng-tao Lv.Methodology: Jia Shi, Shu-tao Gao, Zheng-tao Lv.Project administration: Zheng-tao Lv.Resources: Jia Shi, Shu-tao Gao, Zheng-tao Lv.Software: Jia Shi, Shu-tao Gao, Zheng-tao Lv.Supervision: Zheng-tao Lv, Wei-bin Sheng, Hao Kang.Validation: Jia Shi, Zheng-tao Lv, Wei-bin Sheng, Hao Kang.Visualization: Jia Shi, Shu-tao Gao, Zheng-tao Lv.Writing – original draft: Jia Shi, Shu-tao Gao, Zheng-tao Lv, Wei-bin Sheng, Hao Kang.Writing – review & editing: Jia Shi, Shu-tao Gao, Zheng-tao Lv, Wei-bin Sheng, Hao Kang.Zheng-tao Lv: 0000-0002-8238-7194.


Aims: Rheumatoid arthritis (RA) is characterized by cartilage and bone damage leading to disability. Here, the association between microRNA (miRNA) polymorphisms and susceptibility to RA was evaluated by performing an updated meta-analysis and systematic review.Main methods: An electronic search of databases including PubMed and Embase was performed from inception to December 8, 2017 to retrieve studies investigating the association between miRNA polymorphisms and RA risk. Two reviewers independently screened literature according to the inclusion and exclusion criteria and extracted data. The meta-analysis was conducted using Stata 14.0 software.Key findings: Thirteen case-control studies with 2660 cases and 4098 controls were screened out after a systematic search. One study from the miR-146a rs2910164 G > C polymorphism group and two from the miR-499 rs3746444 T > C polymorphism group were excluded because of deviations from Hardy-Weinberg equilibrium. Pooled analysis demonstrated that miR-146a rs2910164 G > C polymorphism was not significantly associated with susceptibility to RA. However, a significant association was observed between miR-499 rs3746444 T > C polymorphism and RA risk . Subgroup analysis based on ethnicity showed no significant association between miR-499 T > C polymorphism and susceptibility to RA in the Asian population (P > 0.05). However, in Caucasian population, the C allele in the miR-499 T > C polymorphism was a contributor to RA susceptibility in some genetic models .Significance: The miR-146a rs2910164 G > C polymorphism was not associated with susceptibility to RA. In the Caucasian population, the C allele in the miR-499 T > C polymorphism contributed to RA susceptibility. Rheumatoid arthritis (RA), one of the most prevalent chronic inflammatory diseases, is characterized by damage to cartilage and bone leading to disability . It is aRheumatoid arthritis risk was recently shown to be associated with epigenetic regulation including DNA methylation, histone modification, and transcriptional/post-transcriptional regulation . MicroRNA growing body of evidence indicates that single nucleotide polymorphisms (SNPs) in miRNAs may affect RA susceptibility because certain SNPs located in miRNA encoding genes can alter miRNA expression, pri-miRNA and pre-miRNA processing, or miRNA–mRNA interactions .A comprehensive search of the PubMed and Embase databases was performed to retrieve studies investigating the association between miRNA polymorphisms and RA susceptibility published in English up to December 8, 2017. The search terms were as follows: “rheumatoid arthritis” “arthritis” “microRNA” “miRNAs” “polymorphism” and “polymorphisms.” Relevant journals and the references of the included studies were also reviewed.The inclusion criteria of our meta-analysis were as follows: (1) case-control studies; (2) investigation of miRNA polymorphisms and RA susceptibility; (3) detailed numbers of alleles and genotypes between cases and controls; (4) full text published in English; (5) control group consistent with Hardy-Weinberg Equilibrium (HWE); and (6) any specific miRNA with at least two case-control studies to evaluate the association between single nuclear polymorphism and RA susceptibility.The exclusion criteria were as follows: (1) reviews or case reports without controls; (2) no available data reported; and (3) duplicated reports.Two investigators (Zhou and Jiang) screened the literature and extracted data independently according to the inclusion and exclusion criteria. Discrepancies and differences were resolved by a third investigator (Zhu) until consensus was reached. The following data were retrieved: author list, year of publication, ethnicity, sample size, alleles, genotype of each gene polymorphism, and HWE.The odds ratios (ORs) with their corresponding 95% confidence intervals (CIs) were used to assess the strength of the association between polymorphisms in miRNAs and RA. For miR-146a rs2910164 G > C, the dominant (GC + CC vs. GG), recessive (CC vs. GC + GG), heterozygous (GC vs. GG), homozygous (CC vs. GG), and allelic (C vs. G) genetic models were used to calculate pooled ORs. These models were also used to evaluate the miR-499 rs3746444 T > C polymorphism, including the dominant (TC + CC vs. TT), recessive (CC vs. TC + TT), heterozygous (TC vs. TT), homozygous (CC vs. TT), and allelic (C vs. T) models.Q-test was used to assess the between-study heterogeneity and a P-value of 0.1 was considered to indicate significant heterogeneity among studies . Subgroup analysis based on ethnicity showed no significant association between the miR-146a C/G polymorphism and susceptibility to RA in the Asian and Caucasian populations (P > 0.05)  Table , 3A.h = 0.035; TC vs. TT: OR = 1.26, 95% CI = 1.05–1.50, Ph = 0.016; TC/CC vs. TT: OR = 1.26, 95% CI = 1.07–1.50, Ph = 0.011). However, no significant associations were found in CC vs. TT: OR = 1.46, 95% CI = 0.92–2.32, P = 0.558 and CC vs. TC/TT: OR = 1.26, 95% CI = 0.8–1.99, P = 0.79   (all P < 0.001, Table A significant association between the miR-499 rs3746444 T > C polymorphism and RA risk was observed in all populations, as shown in Table A leave-one-out analysis was performed to investigate the influence of each individual study on the pooled ORs Figures , 5B. TheGenetic and epigenetic factors play pivotal roles in cancer and autoimmune diseases. MiRNAs are important for the regulation of the cartilage-invading phenotype of RA synovial fibroblasts, leukocyte activation, and cytokine production, and their roles contribute to our understanding of the mechanisms underlying RA and provide novel therapeutic targets for the treatment of RA .MiR-146a, one of the most extensively investigated miRNAs, exerts significant effects on cancer and autoimmune diseases. MiR-146a is widely expressed and involved in the differentiation and activation of the innate and adaptive immune systems . It suppA single nucleotide polymorphism consisting of the G/C nucleotide substitution in miR-146a rs2910164 could result in the replacement of a G:U pair by a C:U mismatch . HoweverThe mechanism underlying the association between RA and miR-499 was investigated previously. One possible explanation is that mir-499 modulates the expression of regulatory factor X4, thus regulating the human leukocyte antigen DRB1, which is closely associated with RA . MoreoveThe present study had several limitations. Firstly, the variation in sample size and in genotyping methods was a limitation of the study. Secondly, all studies included in our meta-analyses were in accordance with HWE, and because of the limited number of included studies, no publication bias could be tested. Because of the limited quantity and quality of the included studies, the above conclusion needs to be further verified in additional high quality studies.In conclusion, the present meta-analysis showed no significant association between miR-146a and RA risk, which is consistent with previous studies. However, the present study demonstrated the contribution of the C allele in the miR-499 T > C polymorphism to RA susceptibility in the Caucasian population, and this association was not present in the Asian population.XZ conceived and designed the study and contributed to statistical analyses. MZ, BJ, and MX contributed to eligible study collection and data extraction. XZ and BJ prepared the tables and figures. XZ, MZ, and MX wrote and revised the 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.