It is unclear whether vitamin D supplementation reduces risk of falls, and results from randomized controlled trials (RCTs) are conflicting.

The objective of this work is to determine whether 2000 IU/day of supplemental vitamin D₃ decreases fall risk.

VITamin D and OmegA-3 TriaL (VITAL) is a double-blind, placebo-controlled RCT including 25 871 adults, randomly assigned November 2011 to March 2014 and treated for 5.3 years (median).

This is a nationwide study.

Men 50 years or older and women 55 years or older (mean age, 67.1 years) without cancer or cardiovascular disease at baseline participated in this study.

Interventions included vitamin D₃ (cholecalciferol; 2000 IU/day) and/or omega-3 fatty acids (1 g/day) or respective placebos in a 2 × 2 factorial design.

Main outcome measures include 2 or more falls and falls resulting in a doctor or hospital visit.

Baseline serum total 25-hydroxyvitamin D (25[OH]D) level was 77 nmol/L; characteristics were well-balanced between groups. Numbers of participants with 2 or more falls were similar between active and placebo groups (9.8% vs 9.4%). Over 5 years, there were no differences in the proportion having 2 or more falls (odds ratio [OR] = 0.97; 95% CI, 0.90-1.05, P = .50), falls resulting in a doctor visit (OR = 1.03; 95% CI, 0.94-1.13, P = .46), or resulting in a hospital visit (OR = 1.04; 95% CI, 0.90-1.19, P = .61) between groups. Results did not differ between those with baseline 25(OH)D less than 50 vs 50 nmol/L or greater or other cut points.

Daily supplemental vitamin D₃ vs placebo did not decrease fall risk in generally healthy adults not selected for vitamin D insufficiency. This large RCT does not indicate that supplemental vitamin D should be used for primary prevention of falls in the US population.