(P01-059-20) Associations of n-3 Fatty Acids and Fish Intakes with Risk of Alzheimer's Disease and Related Dementia Among Low-Income Black and White Americans

Objectives: Although studies implied that dietary n-3 fatty acids may improve cognitive function, there is a paucity of evidence for such protective effect on the risk of Alzheimer’s disease and related dementias (ADRD) from large multi-ethnic cohorts.

Methods: We evaluated the associations of n-3 fatty acids and fish intakes with risk of ADRD in the Southern Community Cohort Study, which enrolled mostly low-income Americans from 12 southeastern states in 2002–2009. Habitual diet was assessed at baseline. Incident ADRD was identified via Medicare claims data, available from 1999–2016. Current analyses included participants who had 2+ claims after enrollment. We excluded participants who had ADRD diagnosis prior to or within 2 years after enrollment or reported an implausible energy intake or a history of Parkinson’s disease, multiple sclerosis, stoke, or brain cancer at baseline.

Results: Of 23,020 participants (mean age: 61.5 years), 8,363 (36.3%) were men, 13,596 (59.1%) were blacks, and 12,121 (52.7%) had a household income < $15,000/year. During a mean follow-up of 10.8 years, 1,351 incident ADRD cases were identified (mean age at diagnosis: 72.3 years). Marine (docosahexaenoic acid, DHA; eicosapentaenoic acid, EPA) but not plant-based n-3 fatty acids (α-linolenic acid, ALA) were associated with lower risk of ADRD. After adjusting for potential confounders, HRs (95%CI) for the 4th vs. 1st quartiles were 0.81 (0.69, 0.95) for DHA+EPA, 0.85 (0.73, 0.99) for DHA, 0.80 (0.69, 0.93) for EPA, and 0.93 (0.79, 1.08) for ALA. Consistently, fish intake was associated with lower risk of ADRD (HR=0.85 [0.73, 0.99]). HRs (95% CI) were 0.94 (0.90, 0.99) for 1 mg/day of DHA+EPA and 0.97 (0.95, 1.00) for 1 serving/week of fish. Despite no statistical heterogeneity between races, stronger associations were observed among blacks; HRs (95%) for the 4th vs. 1st quartiles were 0.71 (0.58, 0.87) for DHA+EPA and 0.76 (0.62, 0.93) for fish. Similar inverse associations were observed across income groups; specifically, HRs (95%) for the 4th vs. 1st quartiles were 0.79 (0.65,0.97) for DHA+EPA and 0.77 (0.63,0.94) for fish among participants with a household income < $15,000/year.

Conclusions: High intakes of marine n-3 fatty acids and fish are associated with lower risk of ADRD among American adults, regardless of race and socioeconomic status.

Funding Sources: Vanderbilt University Medical Center