To investigate the association between dietary adherence and dementia risk in older adults with elevated blood biomarkers of Alzheimer disease pathology or broader neurobiological risk.
Approach:
Study Design: Longitudinal cohort study analyzing data from 1,865 patients aged 60 years or older without dementia, enrolled in the Swedish National Study on Aging and Care in Kungsholmen.
Biomarker Measurement: Serum biomarkers reflecting Alzheimer disease pathology and neurobiological risk were measured at baseline, including phosphorylated tau, neurofilament light chain, and glial fibrillary acidic protein.
Diet Quality Assessment: Diet quality was assessed using a validated food frequency questionnaire and dietary data collected over 6 years, focusing on three dietary patterns.
Outcome Measurement: Incident all-cause dementia was identified through clinical evaluations, medical records, and death certificates, with a mean follow-up of 8.4 years.
Key Findings:
240 patients developed dementia during follow-up.
Higher adherence to the reversed Empirical Dietary Inflammatory Index was associated with lower dementia risk among patients with elevated biomarker levels (hazard ratio, 0.71; 95% CI, 0.58-0.88 for phosphorylated tau at threonine 217).
The strongest association was observed in patients with elevated phosphorylated tau at threonine 217, showing a 29% lower hazard of dementia.
Associations differed by dietary pattern and biomarker level, with some patterns showing stronger effects in lower biomarker groups.
Interpretation:
The study suggests that blood biomarkers may help identify patients for future diet-based dementia prevention studies.
Limitations:
Self-reported dietary intake and covariates may introduce measurement error and residual confounding.
Biomarkers were measured only at baseline, and dietary data were unavailable beyond the 6-year assessment.
Generalizability may be limited due to the cohort's demographic characteristics.
Conclusion:
The findings indicate a complex relationship between diet adherence and dementia risk that varies by biomarker levels.
