Egg Intake and the Incidence of Alzheimer’s Disease in the Adventist Health Study-2 Cohort Linked with Medicare Data

BACKGROUND: A substantial knowledge gap remains regarding the relationship between modifiable dietary factors and Alzheimer's disease risk. Eggs are a source of key nutrients that support brain health. OBJECTIVES: The aim of this study was to investigate the association between egg consumption and the incidence of Alzheimer's disease. METHODS: Data were drawn from the Adventist Health Study-2, a large, prospective cohort of United States Seventh-day Adventists, linked with Medicare records to identify Alzheimer's disease diagnosis. Diet and lifestyle factors were assessed using a validated food frequency questionnaire. Egg consumption was categorized by frequency, ranging from never/rarely to ≥5 times per week. The analytic sample included 39,498 participants (mean follow-up: 15.3 y), among whom 2858 developed Alzheimer's disease. Multivariable-adjusted Cox proportional hazards models estimated hazard ratios (HRs) and 95% confidence intervals (CIs). Restricted cubic spline analysis was conducted using continuous egg intake (g/d). RESULTS: Egg consumption was inversely associated with Alzheimer's disease risk. Compared with never/rarely consuming eggs, HRs (95% CIs) after adjusting for demographic, lifestyle, food groups, and comorbidities were 0.83 (0.75, 0.92) for 1-3 times per month, 0.83 (0.74, 0.94) for once per week, 0.80 (0.71, 0.90) for 2-4 times per week, and 0.73 (0.60, 0.89) for ≥5 times per week. In the spline model, zero egg intake was curvilinearly associated with an adjusted HR of 1.22 (1.11, 1.34) compared with 10 g/d. CONCLUSIONS: In this health-conscious population, moderate egg consumption was associated with a significantly lower risk of Alzheimer's disease. These findings suggest a potential neuroprotective benefit of nutrients found in eggs when consumed as part of a balanced diet.