Association of fish oil supplementation with risk of incident dementia: A prospective study of 215,083 older adults

Abstract

Background & aims: Evidence linking the use of omega-3 PUFA supplements with incident dementia is scarce. We aim to assess the relationship between fish oil supplementation and incident dementia risk among older adults with different apolipoprotein E (APOE) genotypes in a large population-based cohort.

Methods: We included 215,083 participants (average age: 64.1 ± 2.9 y) without dementia at baseline from UK Biobank study. Fish oil use was assessed by a touch screen questionnaire at baseline. Dietary intake was assessed by a food frequency questionnaire. The APOE genotypes were determined by allele variations on rs429358 and rs7412 from genome-wide genotyping of blood samples. Dementia was diagnosed using the International Classification of Diseases (ICD-9 and ICD-10). Cox proportional hazards regression models were used to calculate the associations of fish oil supplement use with dementia risk.

Results: During an average 7.92 years of follow-up, 2054 participants were diagnosed with dementia. After multivariable adjustment for major risk factors, the use of fish oil supplements was significantly associated with a lower risk of all-cause dementia (p for trend = 0.004). Compared with non-users, the multivariable-adjusted hazard ratio (95% confidence interval) of dementia was 0.87 (0.79-0.96) for fish oil users. A marginal interaction was found between fish oil supplementation and APOE gene variants on the risk of dementia (p for interaction = 0.057). However, fish oil supplementation was not associated with the risk of any subtype of dementia, including Alzheimer's disease (AD), vascular dementia (VD), and frontotemporal dementia (FTD).

Conclusions: Intake of fish oil supplements was associated with lower risk of all-cause dementia among 60-73 y elders. Our findings provide new population-based evidence for linking fish oil supplement use with dementia prevention.

Keywords: Apolipoprotein E; Dementia; Fish oils; Omega-3 fatty acids; UK Biobank cohort study.