Serum 25-hydroxyvitamin D levels and the metabolic syndrome in older persons: a population-based study.

BACKGROUND Recent evidence indicates that a lower plasma level of 25-hydroxyvitamin D (25 OHD) is associated with a higher risk of the metabolic syndrome. It has not been studied in older people with a high prevalence of vitamin D insufficiency. OBJECTIVE This study investigates the association between vitamin D status and the metabolic syndrome in community-dwelling older persons in the Netherlands. DESIGN AND PATIENTS The study is part of the Longitudinal Aging Study Amsterdam, an ongoing cohort study in a representative sample of Dutch older persons. A total of 1286 subjects (629 men and 657 women) between the ages of 65 and 88 years participated in the study. MEASUREMENTS Metabolic syndrome (U.S. National Cholesterol Education Program definition) and its individual components were assessed as well as serum 25 OHD levels. RESULTS Among the participants, the prevalence of the metabolic syndrome was 37·0%. The mean 25 OHD level was 53·3 nM; 47·8% had 25 OHD levels below 50 nM. There was a significantly increased risk of the metabolic syndrome in the subjects with serum 25 OHD levels below 50 nM, compared with that of subjects with levels over 50 nM [odds ratio (OR) = 1·54; 95% confidence interval (CI) 1·23-1·94]. After adjustment for confounders, age, sex, season, years of education, alcohol use, total activity, smoking and PTH, the OR was 1·29 (95% CI 1·00-1·68). The association between vitamin D deficiency and the metabolic syndrome was mainly determined by the components low HDL and (high) waist circumference. CONCLUSIONS Vitamin D deficiency is common in the older population in the Netherlands, and subjects with serum 25 OHD below 50 nM have a higher risk of the metabolic syndrome.