Nut Consumption and Long-Term Risk of All-Cause Dementia: Preliminary Findings from Three Prospective Cohort Studies

Background/Objectives: Nuts have been associated with various health benefits, yet the evidence regarding their relationship with dementia is inconclusive. This study aims to examine the association between nut consumption and long-term risk of dementia across three prospective cohort studies. Methods: We analyzed data from adults aged 45 and older who were free of dementia at baseline in the Health and Retirement Study (HRS, 2013–2020), the Framingham Offspring Study (FOS, 1998–2018), and the Whitehall II Study (WHII, 2002–2016). Nut consumption, including tree nuts and peanuts, was assessed using validated food frequency questionnaires (FFQs) once at baseline in the HRS and repeatedly across multiple waves in the FOS and WHII. Incident all-cause dementia was identified through a validated algorithm in the HRS, expert panel reviews in the FOS, and healthcare record linkages in the WHII. Cox proportional hazards models were used to estimate the cohort-specific association between nut consumption and incident dementia, which were subsequently pooled. Results: Over 190,914 person-years of follow-up, 992 incident dementia cases occurred among 17,349 participants across the three cohorts. After multivariable adjustments, higher nut consumption was associated with a lower risk of dementia, with pooled hazard ratios (HRs) of 0.80 (95% confidence interval [CI]: 0.69–0.94; I2 = 0.0%) for 0.1–5.0 g/day vs. 0 g/day and 0.76 (95% CI: 0.58–0.99; I2 = 40.4%) for >5.0 g/day vs. 0 g/day (p-trend = 0.015). Conclusions: Our findings suggest that higher nut consumption was associated with a lower risk of incident dementia among middle-aged and older adults, with evidence of a dose-response trend observed in pooled analyses. These preliminary results support its inclusion as part of an overall brain-healthy dietary pattern.