Vitamin D and cardiovascular risk among adults with obesity: A systematic review and meta-analysis

Abstract

Background: Obesity is a risk factor for both vitamin D deficiency and cardiovascular disease. A link between vitamin D status optimisation and improved cardiometabolic profile among adults with obesity could inform public health initiatives. Methods: PubMed, Embase and Web of Science were searched for interventional studies examining the effects of vitamin D status improvement on cardiovascular risk factors (anthropometric measures, lipid profile, blood pressure, glucose tolerance) among nondiabetic adults with obesity. Results: Seventeen publications reporting results from 11 different studies were included. Number of participants ranged from 34 to 1179 subjects. Duration was between 6 weeks and 4 years. Vitamin D was administered as a supplement in ten studies (1000 IU daily to 120 000 IU fortnightly). In one study, participants were advised to increase sunlight exposure and dietary vitamin D intake. The random and fixed-effects meta-analysis showed that vitamin D significantly increased systolic blood pressure and LDL-C levels. The fixed-effects model also indicated a significant decrease in triglyceride levels, which was not evident using the random-effects model. Caution should be given to these results given the small number of studies used and the high heterogeneity between studies for the two latter outcomes. Additionally, a subset of eligible studies with compatible data presentation was included in the meta-analysis. Conclusion: This systematic review highlights a paucity of interventional studies examining the effects of vitamin D status improvement on cardiovascular risk factors among otherwise healthy adults with obesity. Large-scale studies at pharmacologically relevant doses and with sufficient duration are warranted. © 2015 Stichting European Society for Clinical Investigation Journal Foundation