Fat Intake at Midlife and Risk of Dementia and Alzheimer’s Disease: A Population-Based Study

<i>Background:</i> Lifestyle and vascular factors have been linked to dementia and Alzheimer’s disease (AD), but the role of dietary fats in the development of dementia is less clear. <i>Methods:</i> Participants were derived from random, population-based samples initially studied in midlife (1972, 1977, 1982, or 1987). Fat intake from spreads and milk products was assessed using a structured questionnaire and an interview. After an average follow-up of 21 years, a total of 1,449 (73%) individuals aged 65–80 years participated in the re-examination in 1998. Altogether 117 persons had dementia. <i>Results: </i>Moderate intake of polyunsaturated fats at midlife decreased the risk of dementia even after adjustment for demographic variables, other subtypes of fats, vascular risk factors and disorders, and apolipoprotein E (ApoE) genotype (OR 0.40, CI 0.17–0.94 for the 2nd quartile vs. 1st quartile), whereas saturated fat intake was associated with an increased risk (OR 2.45, CI 1.10–5.47 for the 2nd quartile). The associations were seen only among the ApoE Ε4 carriers. <i>Conclusions:</i> Moderate intake of unsaturated fats at midlife is protective, whereas a moderate intake of saturated fats may increase the risk of dementia and AD, especially among ApoE Ε4 carriers. Thus, dietary interventions may potentially modify the risk of dementia, particularly among genetically susceptible individuals.