ABSTRACT
OBJECTIVE: Low vitamin D status has been associated with impaired glycemic control in patients with type 2 diabetes. The purpose of our study was to evaluate the effect of vitamin D supplementation on glycemic control in patients with type 2 diabetes. RESEARCH DESIGN AND METHODS: This randomized, double-blind, placebo-controlled trial was conducted in 275 adult patients with type 2 diabetes without insulin treatment. Patients were randomly assigned to receive either vitamin D3 (50,000 IU/month) or placebo for 6 months. To assess the primary outcome of the study, change in HbA(1c), we performed a linear regression analysis. RESULTS: Mean baseline serum 25-hydroxyvitamin D [25(OH)D] increased from 60.6 ± 23.3 to 101.4 ± 27.6 nmol/L and 59.1 ± 23.2 to 59.8 ± 23.2 nmol/L in the vitamin D and placebo group, respectively. Mean baseline HbA(1c) was 6.8 ± 0.5% (51 ± 6 mmol/mol) in both groups. After 6 months, no effect was seen on HbA(1c) (mean difference: ß = 0.4 [95% CI -0.6 to 1.5]; P = 0.42) and other indicators of glycemic control (HOMA of insulin resistance, fasting insulin, and glucose) in the entire study population. Subgroup analysis in patients with a serum 25(OH)D <50 nmol/L or an HbA(1c) level >7% (53 mmol/mol) did not differ the results. CONCLUSIONS: In a well-controlled group of patients with type 2 diabetes, intermittent high-dose vitamin D supplementation did not improve glycemic control.
Subject(s)
Diabetes Mellitus, Type 2/drug therapy , Dietary Supplements , Vitamin D/administration & dosage , Aged , Blood Glucose/analysis , Diabetes Mellitus, Type 2/blood , Double-Blind Method , Female , Humans , Hypoglycemic Agents/administration & dosage , Male , Middle Aged , Vitamin D/analogs & derivatives , Vitamin D/bloodABSTRACT
BACKGROUND: Studies suggest an association between a high TSH and (individual components of) the metabolic syndrome. Only a few studies have been performed in the general older population. OBJECTIVE: This study investigates the association between serum TSH and the metabolic syndrome in a representative sample of older persons in The Netherlands. DESIGN AND PATIENTS: Data of the Longitudinal Aging Study Amsterdam were used, which is an ongoing cohort study in a representative sample of Dutch older persons. A total of 1187 subjects (590 men and 597 women) between the ages of 65 and 88 years participated in the study. MEASUREMENTS: Metabolic syndrome (US National Cholesterol Education Program definition) and its individual components were assessed, as well as serum TSH levels. RESULTS: Among the participants, the prevalence of the metabolic syndrome was 34.2%. The mean serum TSH was 1.9âmU/l. Subjects in the upper quartile with a serum TSH level above 2.28âmU/l (odds ratio (OR)=1.68; 95% confidence interval (CI) 1.19-2.37) had a significantly increased prevalence of metabolic syndrome compared with subjects in the lowest quartile with a serum TSH below 1.04âmU/l. After adjustment for confounders, age, sex, alcohol use, total physical activity, and smoking, the OR was 1.62 (95% CI 1.15-2.32). CONCLUSIONS: Subjects with a serum TSH in the upper quartile have a higher prevalence of metabolic syndrome as compared with subjects with a serum TSH in the lowest quartile.
