Meat consumption and risk of incident dementia: cohort study of 493,888 UK Biobank participants

Background: Worldwide, the prevalence of dementia is increasing and diet as a modifiable factor could play a role. Meat consumption has been cross-sectionally associated with dementia risk, but specific amounts and types related to risk of incident dementia remain poorly understood. Objective: We aimed to investigate associations between meat consumption and risk of incident dementia in the UK Biobank cohort. Methods: Meat consumption was estimated using a short dietary questionnaire at recruitment and repeated 24-h dietary assessments. Incident all-cause dementia comprising Alzheimer disease (AD) and vascular dementia (VD) was identified by electronic linkages to hospital and mortality records. HRs for each meat type in relation to each dementia outcome were estimated in Cox proportional hazard models. Interactions between meat consumption and the apolipoprotein E (APOE) epsilon 4 allele were additionally explored. Results: Among 493.888 participants included, 2896 incident cases of all-cause dementia, 1006 cases of AD, and 490 cases of VD were identified, with mean +/- SD follow-up of 8 +/- 1.1 y. Each additional 25 g/day intake of processed meat was associated with increased risks of incident all-cause dementia (HR: 1.44; 95% CI: 1.24, 1.67; P-trend < 0.001) and AD (HR: 1.52; 95% CI: 1.18, 1.96; P-trend = 0.001). In contrast, a 50-g/d increment in unprocessed red meat intake was associated with reduced risks of all-cause dementia (HR: 0.81; 95% CI: 0.69, 0.95; P-trend = 0.011) and AD (HR: 0.70; 95% CI: 0.53, 0.92; P-trend = 0.009). The linear trend was not significant for unprocessed poultry and total meat. Regarding incident VD. there were no statistically significant linear trends identified, although for processed meat, higher consumption categories were associated with increased risks. The APOE epsilon 4 allele increased dementia risk by 3 to 6 times but did not modify the associations with diet significantly. Conclusion: These findings highlight processed-meat consumption as a potential risk factor for incident dementia, independent of the APOE epsilon 4 allele.