Faculty Collaboration Database

Accelerometer-based physical activity, air pollution and risk of dementia subtypes: a prospective study using UK biobank. Front Public Health 2025;13:1695462

Date

01/29/2026

Pubmed ID

41607889

Pubmed Central ID

PMC12835275

DOI

10.3389/fpubh.2025.1695462

Scopus ID

2-s2.0-105028502930 (requires institutional sign-in at Scopus site)

Abstract

BACKGROUND: The protective effect of physical activity on dementia risk is well established, yet the magnitude of effect remains highly inconsistent, possibly due to various approaches to physical activity measurement and potential moderating effects of environmental factors such as air pollution.

OBJECTIVE: To evaluate the independent and interaction effects of air pollution and accelerometer-based physical activity on incident risks of dementia subtypes.

METHODS: This study included 96,661 participants from the UK Biobank study with accelerometer-derived physical activity measures. Dementia diagnosis was algorithmically defined based on self-reports, primary care, hospital, and mortality records. We assessed five air pollutants, including particulate matters (PM_2.5, PM_2.5-10, PM₁₀), nitrogen dioxide (NO₂), and nitrous oxides (NO_x). Multivariable-adjusted Cox proportional hazard models were employed to estimate the associations between physical activity, air pollution, and the risks of Alzheimer's Disease (AD) and Vascular Dementia (VaD). Hazard ratios (HRs) and 95% confidence intervals (CIs) were calculated. Several sensitivity analyses were conducted to assess the robustness of the results.

RESULTS: A one-IQR (10.13 milli-gravity) higher level of physical activity was significantly associated with a 30% lower risk of AD (HR = 0.7, 95% CI: 0.57-0.86, p < 0.001) and a 32% lower risk of VaD (HR = 0.68, 95% CI: 0.5-0.91, p < 0.05). Exposure to NO₂ was significantly associated with an increased incident risk of AD, while exposure to PM_2.5, PM_2.5-10, PM₁₀, and NO₂ was associated with an increased risk of VaD. Results from models with interaction terms indicate that the protective effect of physical activity against AD was attenuated among individuals exposed to higher levels of PM_2.5 and NO_2, and that the effect of physical activity against VaD was attenuated by higher PM_2.5-10 exposure.

SIGNIFICANCE: This study provides new evidence on the independent and interactive effects of objectively measured physical activity and air pollution on the risks of dementia subtypes, thereby improving the biological specificity of these associations.

Author List

Zhang Y, Xu W

Author

Wei Xu PhD Assistant Professor in the Institute for Health and Humanity department at Medical College of Wisconsin

MESH terms used to index this publication - Major topics in bold

Accelerometry
Aged
Air Pollutants
Air Pollution
Dementia
Exercise
Female
Humans
Male
Middle Aged
Particulate Matter
Proportional Hazards Models
Prospective Studies
Risk Factors
United Kingdom