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 50,000IU vitamin D supplements (n=34) or placebo (n=34) every 2weeks for 12weeks. 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±10.7mg/dL, P=0.004), serum insulin levels (-3.6±5.3 vs. -0.9±3.5 μIU/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±30.2mg/dL, P=0.001), total- (-8.7±20.9 vs. +11.0±27.4mg/dL, P=0.001) and LDL-cholesterol (-11.1±17.9 vs. +5.9±27.5mg/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±3.7mg/L, P<0.001), and significant increases plasma total antioxidant capacity (+26.2±99.8 vs. -86.3±127.5mmol/L, P<0.001) and glutathione levels (+292.3±172.4 vs. +48.9±208.9μmol/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 50,000IU vitamin D supplement every 2weeks for 12weeks in MMT patients had beneficial effects on psychological symptoms and few metabolic profiles.