To examine whether long-term fish oil (FO) supplementation is associated with a lower risk of mobility disability and enhances benefits of physical activity.
1635 sedentary adults aged 70 to 89 years from the Lifestyle Interventions and Independence for Elders (LIFE) single-blinded randomized, multi-center clinical trial, which compared a structured physical activity (PA) program to a health education (HE) program. Primary outcome was incident major mobility disability (MMD), defined by loss of ability to walk 400m, measured every 6 months for an average of 2.6 years. Secondary outcomes included persistent mobility disability (PMD), Short Physical Performance Battery (SPPB), 400m walk speed, and grip strength.
A third of participants reported using FO at baseline (456, 28%; mean age, 78.5 years; 70.5% women). MMD was experienced by 131 participants (28.7%) in the FO group and 405 (34.4%) participants in the nonuser group. After adjusting for confounders, FO supplementation was associated with a lower risk (hazard ratio [HR], 0.78; 95% CI, 0.64-0.96) of incident MMD. However, there was no interaction (P
= .19) between FO supplementation and PA intervention for MMD. For the secondary outcome of PMD, the intervention association differed by supplementation (P
= .002) with PA intervention associations of (HR, 1.36; 95% CI, 0.83-2.23) for users and (HR, 0.61; 95% CI, 0.46-0.81) for nonusers. Changes in physical performance outcomes were not modified by baseline FO supplementation or combination with PA.
FO supplementation was associated with a lower risk of major mobility disability in low to moderate functioning older adults. However, supplementation did not enhance the benefit of physical activity on risk of mobility disability. These results are hypothesis generating and need to be confirmed in randomized trials.