Low vitamin D levels in Northern American adults with the metabolic syndrome.

Metabolic syndrome (MetS), is a constellation of cardiometabolic disease risk factors, that affects 1 in 3 US adults and predisposes to increased risks for both diabetes and cardiovascular disease. While epidemiological studies show low vitamin D [(25(OH)D] levels in MetS, there is sparse data on vitamin D status in MetS patients in North America. Thus, the aim of our study was to examine plasma vitamin D concentration among adults with MetS in Northern California (sunny climate), but without diabetes or cardiovascular disease. 25(OH)D levels were significantly decreased in MetS compared to controls. 8 % of controls and 30% of MetS North American adult subjects were deficient in 25(OH)D (<20 ng/ml; p=0.0236, Controls vs. MetS). There were no significant differences between the groups with respect to blood sampling in winter and summer months, total calcium and phosphate, and creatinine levels. Vitamin D levels were significantly inversely correlated with fasting glucose (r=-0.29, p=0.04) and HOMA (r=-0.34, p=0.04). Future studies of vitamin D supplementation in these subjects on subsequent risk of diabetes will prove instructive with respect to potential health claims in these high risk patients with MetS.