Abstract
Objective Numerous cross-sectional studies have noted significant negative associations between circulating levels of vitamin D and cardio- metabolic risk factors, highlighting potential extra-skeletal functions of this sterol hormone. Prospective studies, however, have been limited and hence no cause and effect relations can be inferred. This study aims to determine whether vitamin D correction can reverse already established manifestations of the metabolic syndrome (MetS).
Methods A total of 59 adult non-diabetic, overweight and obese Saudis (31 males, 28 females) were randomly recruited in this prospective 1-year interventional study. Anthropometry and biochemical evaluation were performed, including determination of serum vitamin D, calcium and phosphorous concentrations, as well as fasting blood glucose and lipid profile. Subjects were advised to regularly expose themselves to sunlight and increase intake of vitamin D-rich foods. All measurements were repeated 6 and 12 months later.
Results At the initial baseline visit, the prevalence of both low HDL-C and hypertension was significantly increased among patients with vitamin D deficiency (p＜0.05), even after adjusting for gender and BMI. Overall prevalence of MetS patients by the modified NHANES ATP III definition decreased from 25.2% to 13.0% and this was largely due to a parallel decrease in the prevalence of low HDL-cholesterol, triglycerides and hypertension.
Conclusion Optimization of vitamin D levels through sun exposure and increased intake of a vitamin D-rich diet can lead to an improved cardiometabolic profile, offering a promising non-pharmacologic approach in the prevention of MetS manifestations.