Vitamin D, omega-3 plus strength exercises may reduce cancer risk in older adults

Daily supplementation with vitamin D3 and omega-3 fatty acids, in conjunction with a strength exercise program, may reduce the risk for cancer in adults aged 70 years and older, according to results of a randomized controlled trial.

“Based on our findings, with the triple combination, we would need to treat 35 persons (95% CI, 26-137) in order to prevent one incident case of cancer at 3 years follow-up,” Heike A. Bischoff-Ferrari, DrPH, the director of the department of aging medicine; Healthy Aging Check-up; and the Center on Aging and Mobility at the University of Zurich, and colleagues wrote in Frontiers in Aging. “These results may shape the future mind-set toward a multicomponent prevention strategy of cancer.”

In the DO-HEALTH trial, a 3-year, multicenter 2x2x2 factorial design double-blind study, Bischoff-Ferrari and colleagues evaluated the individual and combined benefit of 2,000 IU of vitamin D3 per day, 1 g of marine omega-3s per day and a simple home strength exercise (SHEP) program compared with placebo and control exercise. Their study cohort included 2,157 “generally healthy” community-dwelling adults aged 70 years or older in Switzerland, Germany, Austria, France and Portugal.

From December 2012 to December 2017, the researchers randomly assigned participants to eight treatment groups with block sizes of 16 individuals. Bischoff-Ferrari and colleagues conducted in-person interviews every 3 months over an average of 2.99 years of follow up.

At baseline, the mean age of the study cohort was 74.9 years; 61.7% of participants were women and the mean BMI was 26.3 kg/m². A majority of participants exercised three or more times per week and reported an average of 3.3 comorbidities. Initially, 24% of participants were taking vitamin D3 supplements.

After follow up, 119 invasive cancer events were reported, 81 of which were verifiable.

For the three individual treatments, vitamin D3 supplementation appeared to have the greatest effect on cancer risk versus the control group (adjusted HR [aHR] = 0.76; 95% CI, 0.49-1.18) compared with omega-3 supplementation (aHR = 0.7; 95% CI, 0.44–1.09) and SHEP (aHR = 0.74; 95% CI, 0.48–1.15), Bischoff-Ferrari and colleagues reported. For combinations of two treatments, vitamin D3 plus SHEP had a higher adjusted hazard ratio (aHR = 0.56; 95% CI, 0.3-1.04) compared with omega-3s plus vitamin D3 (aHR = 0.53, 95% CI, 0.28-1) and omega-3s plus SHEP (aHR = 0.52; 95% CI, 0.28-0.97). For all three treatments combined, the adjusted hazard ratio was 0.39 (95% CI, 0.18–0.85), according to the researchers. Sensitivity analyses increased the adjusted hazard ratio to 0.51 (95% CI, 0.27-0.98) for a combination of the three treatments.

Data on individual cancers were too low for reliable interpretation of possible risk reduction, Biscoff-Ferrari and colleagues reported.

“Our results suggest that the simple strength home exercise program may effectively contribute to cancer prevention in combination with supplemental omega-3s and in combination with both supplemental omega-3s and vitamin D3,” the researchers wrote.