Blood Vitamin D Status and Metabolic Syndrome in the General Adult Population: A Dose-Response Meta-Analysis
The Journal of Clinical Endocrinology & Metabolism
Sang Yhun Ju, Hyun Suk Jeong, Do Hoon Kim
Received: September 23, 2013, Accepted: December 04, 2013, Published Online: January 01, 2014
Increasing evidence has suggested an association between blood vitamin D levels and metabolic syndrome.
Objective: Our objective was to determine the relationship between blood vitamin D status and metabolic syndrome in the general adult population, using a dose-response meta-analysis.
Data Source:We searched the PubMed, EMBASE, Web of Science, and Cochrane Library databases through July 2013 to identify relevant studies.
Study Selection:Observational studies, reporting risk ratios with a 95% confidence interval (CI) for metabolic syndrome in ≥3 categories of blood 25-hydroxyvitamin D 25(OH)D levels, were selected.
Data Extraction:Data extraction was performed independently by 2 authors, and the quality of the studies was evaluated using the Risk of Bias Assessment Tool for Nonrandomized Studies.
Data Synthesis:The pooled odds ratio of metabolic syndrome per 25 nmol/l increment in the serum/plasma 25(OH)D concentration was 0.87 (95% CI = 0.83–0.92, I2 = 85%), based on 16 “cross-sectional studies” and 1.00 (95% CI = 0.98–1.02, I2= 0%) for 2 “cohort and nested case-control studies”. The dose-response meta-analysis showed a generally linear, inverse relationship between 25(OH)D levels and metabolic syndrome in the cross-sectional studies (P for linear trend <0.001).
Conclusions:Blood vitamin D levels were associated with a risk of metabolic syndrome in cross-sectional studies but not in longitudinal studies. Randomized, clinical trials will be necessary to address the issue of causality and to determine whether vitamin D supplementation is effective for the prevention of metabolic syndrome.
Affiliations
1 Department of Family Medicine, College of Medicine, The Catholic University of Korea;
2 Department of Preventive Medicine, the Catholic University of Korea;
3 Department of Family Medicine, Korea University Ansan Hospital