Yvonne H M Krul-Poel1, Sanne Westra1, Edwin ten Boekel2, Marieke M ter Wee3, Natasja M van Schoor4, Hans van Wijland5, Frank Stam1, Paul T A M Lips6, Suat Simsek7. 1. Department of Internal Medicine, Medical Center Alkmaar, Alkmaar, the Netherlands. 2. Department of Clinical Chemistry, Medical Center Alkmaar, Alkmaar, the Netherlands. 3. Amsterdam Rheumatology and Immunology Center, VU University Medical Center, Amsterdam, the Netherlands. 4. Department of Epidemiology and Biostatistics, EMGO Institute for Health and Care Research, VU University Medical Center, Amsterdam, the Netherlands. 5. Department of General Practice, DIAZON, Alkmaar, the Netherlands. 6. Department of Internal Medicine/Endocrinology, VU University Medical Center, Amsterdam, the Netherlands. 7. Department of Internal Medicine, Medical Center Alkmaar, Alkmaar, the Netherlands Department of Internal Medicine/Endocrinology, VU University Medical Center, Amsterdam, the Netherlands s.simsek@mca.nl.
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: β = 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.
RCT Entities:
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: β = 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.