title: Vitamin D Deficiency Increases the Risk of Gestational Diabetes Mellitus: A Meta-Analysis of Observational Studies.
abstract: The results investigating the relationship between vitamin D levels and gestational diabetes mellitus (GDM) are inconsistent. Thus, we focused on evaluating the association of vitamin D deficiency with GDM by conducting a meta-analysis of observed studies. A systematic literature search was conducted via PubMed, MEDLINE, and Cochrane library to identify eligible studies before August 2015. The meta-analysis of 20 studies including 9209 participants showed that women with vitamin D deficiency experienced a significantly increased risk for developing GDM (odds ratio (OR) = 1.53; 95% confidence intervals (CI), 1.33, 1.75) with a little heterogeneity (I² = 16.20%, p = 0.252). A noteworthy decrease of 4.93 nmol/L (95% CI, -6.73, -3.14) in serum 25(OH)D was demonstrated in the participants with GDM, and moderate heterogeneity was observed (I² = 61.40%, p = 0.001). Subgroup analysis with study design showed that there were obvious heterogeneities in nested case-control studies (I² > 52.5%, p < 0.07). Sensitivity analysis showed that exclusion of any single study did not materially alter the overall combined effect. In summary, the evidence from this meta-analysis indicates a consistent association between vitamin D deficiency and an increased risk of GDM. However, well-designed randomized controlled trials are needed to elicit the clear effect of vitamin D supplementation on prevention of GDM.
authors.affiliation: Department of Labor Hygiene and Environmental Health, School of Public Health of Soochow University, 199 Renai Road, Suzhou 215123, China. zhangmengxi_suda@hotmail.com.
authors.forename: Meng-Xi
authors.initials: MX
authors.lastname: Zhang
authors.affiliation: Department of Labor Hygiene and Environmental Health, School of Public Health of Soochow University, 199 Renai Road, Suzhou 215123, China. panguotao_suda@hotmail.com.
authors.forename: Guo-Tao
authors.initials: GT
authors.lastname: Pan
authors.affiliation: Department of Labor Hygiene and Environmental Health, School of Public Health of Soochow University, 199 Renai Road, Suzhou 215123, China. justxiangwang@hotmail.com.
authors.forename: Jian-Fen
authors.initials: JF
authors.lastname: Guo
authors.affiliation: Department of Nutrition and Food Hygiene, School of Public Health, Soochow University, 199 Renai Road, Suzhou 215123, China. bingyanli@suda.edu.cn.
authors.forename: Bing-Yan
authors.initials: BY
authors.lastname: Li
authors.affiliation: Department of Nutrition and Food Hygiene, School of Public Health, Soochow University, 199 Renai Road, Suzhou 215123, China. qinliqiang@suda.edu.cn.
authors.forename: Li-Qiang
authors.initials: LQ
authors.lastname: Qin
authors.affiliation: Department of Labor Hygiene and Environmental Health, School of Public Health of Soochow University, 199 Renai Road, Suzhou 215123, China. zhangzengli@suda.edu.cn.
authors.forename: Zeng-Li
authors.initials: ZL
authors.lastname: Zhang
mesh_terms: D000328:Adult; D016022:Case-Control Studies; D016640:Diabetes, Gestational / Q000097:blood / Q000209:etiology* / Q000517:prevention & control; D019587:Dietary Supplements; D005260:Female; D006801:Humans; D016239:MEDLINE; D016017:Odds Ratio; D011247:Pregnancy; D012307:Risk Factors; D014807:Vitamin D / Q000031:analogs & derivatives / Q000097:blood; D014808:Vitamin D Deficiency / Q000150:complications*
chemical_list: D014807:Vitamin D; C104450:25-hydroxyvitamin D
keywords: gestational diabetes mellitus; meta-analysis; pregnancy; vitamin D deficiency