Clinical trial of the effects of vitamin D supplementation on psychological symptoms and metabolic profiles in maintenance methadone treatment patients

Background: Vitamin D deficiency may be associated with some complications including nonspecific musculoskeletal pain and periodontal disease in maintenance methadone treatment (MMT) patients. This study was designed to determine the effect of vitamin D supplementation on psychological symptoms and metabolic profiles in MMT patients. Methods: This randomized, double-blind, placebo-controlled, clinical trial was carried out among 68 MMT patients. Participants were randomly allocated to receive either 50,000 IU vitamin D supplements (n = 34) or placebo (n= 34) every 2 weeks for 12 weeks. Fasting blood samples were taken at baseline and post-intervention to evaluate relevant variables. Results: After the 12-week intervention, serum 25(OH) vitamin D levels significantly increased in the intervention group compared with the placebo group (+ 8.1 +/- 4.9 vs. -0.4 +/- 3.0, P < 0.001). In addition, vitamin D supplementation significantly improved Pittsburgh Sleep Quality Index (-1.5 +/- 2.2 vs. -0.2 +/- 2.3, P = 0.02) and Beck Depression Inventory (-4.8 +/- 7.3 vs. -1.5 +/- 6.1, P= 0.04) compared with the placebo. Patients who received vitamin D supplements had significantly decreased fasting plasma glucose (-7.5 +/- 10.6 vs. + 0.3 +/- 10.7 mg/dL, P= 0.004), serum insulin levels (-3.6 +/- 5.3 vs. -0.9 +/- 3.5 mu IU/mL, P= 0.01), homeostasis model of assessment-insulin resistance (-1.0 +/- 1.3 vs. -0.2 +/- 0.7, P= 0.003), serum triglycerides (-9.6 +/- 30.8 vs. + 15.6 +/- 30.2 mg/dL, P= 0.001), total-(-8.7 +/- 20.9 vs. + 11.0 +/- 27.4 mg/dL, P= 0.001) and LDL-cholesterol (-11.1 +/- 17.9 vs. + 5.9 +/- 27.5 mg/dL, P= 0.004) compared with the placebo. Additionally, vitamin D intake resulted in a significant decrease in serum high sensitivity C-reactive protein (-2.2 +/- 4.2 vs. + 2.0 +/- 3.7 mg/L, P < 0.001), and significant increases plasma total antioxidant capacity (+ 26.2 +/- 99.8 vs. -86.3 +/- 127.5 mmol/L, P < 0.001) and glutathione levels (+ 292.3 +/- 172.4 vs. + 48.9 +/- 208.9 mu mol/L, P < 0.001) compared with the placebo. There was no significant effect of vitamin D supplementation on serum HDL-cholesterol, and other markers of insulin metabolism, inflammation and oxidative stress. Conclusions: Totally, taking 50,000 IU vitamin D supplement every 2 weeks for 12 weeks in MMT patients had beneficial effects on psychological symptoms and few metabolic profiles.