Association of low vitamin D levels with metabolic syndrome in hemodialysis patients

Low vitamin D levels have been linked to metabolic syndrome in the general population. In the present study, the relationship between inadequate serum concentrations of vitamin D and metabolic syndrome in patients with end-stage renal disease undergoing hemodialysis was explored. In a cross-sectional setting, 145 patients undergoing maintenance hemodialysis were enrolled. Metabolic syndrome was defined using the International Diabetes Federation criteria. Serum concentration of 25(OH) vitamin D was determined by a commercially available enzyme immunosorbent assay method. The prevalence of metabolic syndrome was 53.1%. The prevalence rate of severe vitamin D deficiency (<5ng/mL) was 3.4%, mild vitamin D deficiency (5-15ng/mL) 31.0%, vitamin D insufficiency (16-30ng/mL) 36.6%, and vitamin D sufficiency (>30ng/mL) 29.0%. With the increasing number of metabolic abnormalities, vitamin D levels significantly decreased (P for trend=0.028). Among the components of metabolic syndrome, vitamin D deficiency was significantly associated with central obesity (odds ratio [OR], 95% confident interval [CI]=2.80, 1.11-7.04, P=0.028). A positive, but nonsignificant association between vitamin D deficiency and raised fasting plasma glucose was noted (OR, 95% CI=2.40, 0.94-6.11, P=0.067). Both vitamin D deficiency and insufficiency were significantly associated with an increased likelihood of having metabolic syndrome (P<0.05). In a final model controlling for age, sex, and parathyroid hormone levels, vitamin D deficiency increased the odds of having metabolic syndrome by more than threefold (OR, 95% CI=3.26, 1.30-8.20, P=0.012). Low levels of vitamin D are frequent among hemodialysis patients and are associated with the metabolic syndrome.