Association of Plasma n-3 Polyunsaturated Fatty Acid Levels and the Prevalence of Frailty in Older Adults: A Cross-Sectional Analysis of UK Biobank.

Background: Circulating levels of n-3 polyunsaturated fatty acids (PUFAs) have been associated with frailty among Koreans (a population with a high intake of fish), but whether this association exists in Western populations with low fish intake is unknown. The present study examined the hypothesis that the prevalence of frailty was inversely associated with plasma levels of n-3 PUFAs, with the intake of oily fish, and with fish oil supplementation in older adults in the United Kingdom.

Methods: UK Biobank including 79 330 adults aged ≥65 years with dietary data, and 18 802 participants with plasma fatty acid data were used. Frailty was defined using the Cardiovascular Health Study index, plasma levels of n-3 PUFAs were measured by nuclear magnetic resonance, and intake of oily fish and/or fish oil supplements was collected via food frequency questionnaire.

Results: Frailty prevalence was inversely associated with n-3 PUFA levels [odds ratios (OR) per SD: 0.86, 95% confidence interval (CI) 0.79-0.94; p < .001], with oily fish intake (never vs ≥2 servings per week; OR 0.59, 95% CI 0.52-0.68, p < .001), and with the use of fish oil supplements (OR 0.72; 95% CI 0.66-0.78; p < .001) after adjusting for confounding factors. All 3 exposures were also associated with each frailty criterion, particularly low physical activity and walking pace.

Conclusions: Inverse associations between plasma n-3 PUFA levels and measures of frailty suggest that higher intakes of oily fish or the use of fish oil supplements may help prevent frailty in older adults in the United Kingdom.