Combined Vitamin D, Omega-3 Fatty Acids, and a Simple Home Exercise Program May Reduce Cancer Risk Among Active Adults Aged 70 and Older: A Randomized Clinical Trial.
Level 2 - randomized trial
Individual randomized controlled trial (pre-defined exploratory analysis)
PubMed 35821820 · doi:10.3389/fragi.2022.852643
What was done
In the DO-HEALTH trial, 2,157 community-dwelling adults aged 70 and older (mean age 74.9 years, 61.7% women, across five European countries) were randomized in a 2 × 2 × 2 factorial, double-blind design. Participants received 2,000 IU/day vitamin D3, 1 g/day marine omega-3s, a simple home strength exercise program (SHEP), or their respective placebos/control exercise over a median follow-up of 2.99 years. The primary outcome for this pre-defined exploratory analysis was the time-to-development of any verified invasive cancer in an adjusted intent-to-treat framework.
What was found
A total of 81 verified invasive cancer cases occurred. Individual interventions did not reach statistical significance alone: vitamin D3 HR 0.76 (95% CI 0.49–1.18; 36 vs. 45 cases), omega-3s HR 0.70 (95% CI 0.44–1.09; 32 vs. 49 cases), and SHEP HR 0.74 (95% CI 0.48–1.15; 35 vs. 46 cases). For two-treatment combinations, adjusted HRs were 0.53 (95% CI 0.28–1.00) for omega-3s plus vitamin D3, 0.56 (95% CI 0.30–1.04) for vitamin D3 plus SHEP, and 0.52 (95% CI 0.28–0.97) for omega-3s plus SHEP. The combination of all three interventions showed a cumulative risk reduction with an adjusted HR of 0.39 (95% CI 0.18–0.85; 4 vs. 12 cases).
Why it matters
This study suggests that combining multiple low-cost, low-risk public health interventions—supplementation with vitamin D3 and omega-3s alongside a basic home exercise regimen—may exert additive preventive effects against invasive cancer in older adults.
Limits
This was an exploratory analysis rather than the primary trial endpoint, and the total number of cancer cases was small (81 events total, with only 4 events in the triple-combination arm). The 3-year follow-up period is relatively brief for evaluating cancer incidence. In addition, participants were largely healthy, vitamin D-replete (only 40.7% had baseline 25-OH vitamin D <20 ng/ml), and physically active (83%), which may limit generalizability to frailer or deficient populations.