Long-term ambient air pollution exposure and prospective change in sedentary behaviour and physical activity in individuals at risk of type 2 diabetes in the UK

Abstract

Background: Air pollution may be a risk factor for physical inactivity and sedentary behaviour (SED) through discouraging active lifestyles, impairing fitness and contributing to chronic diseases with potentially important consequences for population health.

Methods: Using generalized estimating equations, we examined the associations between long-term particulate matter with diameter ≤2.5 μm (PM2.5), ≤10 μm (PM10) and nitrogen dioxide (NO2) and annual change in accelerometer-measured SED, moderate-to-vigorous physical activity (MVPA) and steps in adults at risk of type 2 diabetes within the Walking Away from Type 2 Diabetes trial. We adjusted for important confounders including social deprivation and measures of the built environment.

Results: From 808 participants, 644 had complete data (1605 observations; 64.7% men; mean age 63.86 years). PM2.5, NO2 and PM10 were not associated with change in MVPA/steps but were associated with change in SED, with a 1 ugm-3 increase associated with 6.38 (95% confidence interval: 0.77, 12.00), 1.52 (0.49, 2.54) and 4.48 (0.63, 8.34) adjusted annual change in daily minutes, respectively.

Conclusions: Long-term PM2.5, NO2 and PM10 exposures were associated with an annual increase in SED: ~11-22 min/day per year across the sample range of exposure (three standard deviations). Future research should investigate whether interventions to reduce pollution may influence SED.

Keywords: air pollution; chronic disease; physical activity.

Fig. 1

Cohort definition. BMI: Body Mass Index; PM2.5: Particulate matter ≤2.5 μm; NO₂: Nitrogen dioxide; PM10: particulate matter ≤10.0 μm; SED: Time spent in sedentary behaviour; MVPA: Time spent in moderate-to-vigorous physical activity.

Fig. 2

SD change in daily MVPA and SED per one standard deviation increase in pollutant concentration. Bars represent 95% confidence interval. Model 1: Standard adjustments (Age, ethnicity, sex, smoking status, past medical history of cardiovascular disease, past medical history of respiratory disease, treatment group, change in wear time between accelerometery measures, SED/MVPA/steps/LPA at start of observation, body mass index, season of accelerometer measurements). Model 2: Standard adjustments + social deprivation + greenspace + measures of built environment (road density, footpath density, junctions, cul-de-sacs, connected intersections) + occupation. MVPA: Time spent in moderate-to-vigorous physical activity; SED: Time spent in sedentary behaviour; PM2.5: Particulate matter ≤2.5 μm; NO₂: Nitrogen dioxide; PM10: particulate matter ≤10.0 μm; SD: Standard deviation.