Integrating noise as a risk factor in studies of Alzheimer's disease and dementia: Guidance for epidemiologic research.

Noise exposure is increasingly recognized as a modifiable environmental risk factor for Alzheimer's disease and related dementias (ADRD), yet its integration into epidemiologic research remains limited. We reviewed international noise mapping resources, exposure metrics, and analytic approaches relevant to ADRD studies. Mechanistic pathways and methodological challenges were synthesized from recent studies via expert knowledge. We present a stepwise framework for integrating noise into ADRD research, detailing metric selection, spatiotemporal assignment, and analytic guardrails. Our review recommends the application of 24-hour average, nighttime, and event-based metrics, and stresses that health effects may occur at low noise levels. We further underscore the importance of accounting for indoor, occupational, and life course exposures. Rigorous noise exposure assessment and transparent reporting will improve comparability and causal inference in ADRD studies. Future research should harmonize exposure metrics, integrate co-exposures (e.g., air pollution), and clarify etiologically relevant windows to strengthen prevention strategies.