Effects of vitamin D3, omega-3s, and a simple strength training exercise program on bone health: the DO-HEALTH randomized controlled trial

Evidence on the effects of Vitamin D, omega-3s, and exercise on areal bone mineral density (aBMD) in healthy older adults is limited. We examined whether vitamin D3, omega-3s, or a simple home-based exercise program (SHEP), alone or in combination, over 3 years, improve lumbar spine (LS), femoral neck (FN), or total hip (TH) aBMD assessed by DXA. Areal BMD was a secondary outcome in DO-HEALTH, a 3-year, multicenter, double-blind, randomized 2 x 2 x 2 factorial design trial in generally healthy older adults age >= 70 years. The study interventions were vitamin D3 (2000IU/d), omega-3s (1 g/d), and SHEP (3 x 30 min/wk), applied alone or in combination in eight treatment arms. Mixed effects models were used, adjusting for age, sex, BMI, prior fall, study site, and baseline level of the outcome. Main effects were assessed in the absence of an interaction between the interventions. Subgroup analyses by age, sex, physical activity level, dietary calcium intake, serum 25(OH)D levels, and fracture history were conducted. DXA scans were available for 1493 participants (mean age 75 years; 80.4% were physically active, 44% had 25(OH)D levels <20 ng/mL). At the LS and FN sites, none of the treatments showed a benefit. At the TH, vitamin D versus no vitamin D treatment showed a significant benefit across 3 years (difference in adjusted means [AM]: 0.0035 [95% CI, 0.0011, 0.0059] g/cm). Furthermore, there was a benefit for vitamin D versus no vitamin D treatment on LS aBMD in the male subgroup (interaction P = .003; triangle AM: 0.0070 [95% CI, 0.0007, 0.0132] g/cm). Omega-3s and SHEP had no benefit on aBMD in healthy, active, and largely vitamin D replete older adults. Our study suggests a small benefit of 2000 IU vitamin D daily on TH aBMD overall and LS aBMD among men; however, effect sizes were very modest and the clinical impact of these findings is unclear.