Alcohol use disorder and muscle weakness: Original study of the effect of vitamin D supplementation in ambulatory participants with alcohol use disorder.

INTRODUCTION: Chronic alcohol-related myopathy presents with proximal muscle weakness. We studied the effect of vitamin D supplementation on muscle weakness in adults with alcohol use disorder. METHOD: Randomized controlled trial. Participants were community-dwelling adults with alcohol use disorder. Participants allocated to VIDIO, vitamin D intensive outreach, received bimonthly oral doses of 50,000‒100,000 IU cholecalciferol for 12 months. Participants allocated to CAU, care as usual, received prescriptions of once-a-day tablets containing 800 IU cholecalciferol and 500 mg calcium carbonate. Data included demographic variables, laboratory tests, alcohol use, and rating scales of help-seeking and support. Main outcomes were the participants' quadriceps maximum voluntary contractions (qMVC) and serum-25(OH)vitamin D concentrations, 25(OH)D. RESULTS: In 66 participants, sex ratio 50/16, mean age 51 year, alcohol use was median 52 [IQR 24‒95] drinks per week. Baseline qMVC values were 77% (SD 29%) of reference values. Laboratory tests were available in 44/66 participants: baseline 25(OH)D concentrations were 39.4 (SD 23.7) nmol/L. Thirty-one participants with 25(OH)D concentrations <50 nmol/L received either VIDIO or CAU and improved in qMVC, respectively with mean 51 (P<0.05) and 62 Newton (no P-value because of loss of follow-up) after one year of treatment. Vitamin D status increased with mean +56.1 and +37.4 nmol/L, respectively in VIDIO and CAU. CONCLUSION: The qMVC values improved during vitamin supplementation in adults with vitamin D deficiency and alcohol use disorder. Despite higher 25(OH)D concentrations in VIDIO, in terms of muscle health no advise could be given in favor of one vitamin strategy over the other. TRIAL REGISTRATION: Netherlands Trial Register (NTR) identifier: NTR4114.