Air pollution, physical activity and ischaemic heart disease: a prospective cohort study of interaction effects

Abstract

ObjectiveTo assess a possible interaction effect between physical activity and air pollution on first incidence of ischaemic heart disease (IHD).DesignProspective cohort study.SettingUmeå, Northern Sweden.ParticipantsWe studied 34 748 adult participants of Västerbotten Intervention Programme cohort from 1990 to January 2014. Annual particulate matter concentrations (PM2.5 and PM10) at the participants’ residential addresses were modelled and a questionnaire on frequency of exercise and active commuting was completed at baseline. Cox proportional hazards modelling was used to estimate (1) association with physical activity at different levels of air pollution and (2) the association with particulate matter at different levels of physical activity.OutcomeFirst incidence of IHD.ResultsOver a mean follow-up of 12.4 years, there were 1148 IHD cases. Overall, we observed an increased risk of IHD among individuals with higher concentrations of particles at their home address. Exercise at least twice a week was associated with a lower risk of IHD among participants with high residential PM2.5 (hazard ratio (HR) 0.60; 95% CI: 0.44 to 0.82) and PM10 (HR 0.55; 95% CI: 0.4 to 0.76). The same beneficial effect was not observed with low residential PM2.5 (HR 0.94; 95% CI: 0.72 to 1.22) and PM10 (HR 0.99; 95% CI: 0.76 to 1.29). An increased risk associated with higher long-term exposure to particles was only observed among participants that exercised in training clothes at most one a week and among those not performing any active commuting. However, only the interaction effect on HRs for exercise was statistically significant.ConclusionExercise was associated with a lower risk of first incidence of IHD among individuals with higher residential particle concentrations. An air pollution-associated risk was only observed among those who exercised less. The findings support the promotion of physical activity and a mitigation of air pollution.

PM2.5 exposure and olfactory functions

“…Since exposure to PM2.5 in Umeå has been shown to be associated with an increased risk of developing dementia (Oudin et al 2018) as well as the incidence of cardiovascular disease (Raza et al 2021), healthier older adults may be over-represented at higher exposure levels. Competing risks and selection may therefore be a source of bias in the present study, especially in older ages, which could theoretically at least partly explain our findings.…”

Practicing Outdoor Physical Activity: Is It Really a Good Choice? Short- and Long-Term Health Effects of Exercising in a Polluted Environment

“…Endes et al examined physical activity as a modifier of the association between air pollution and arterial stiffness in 2823 adults (50-81 years old), they found that the probability of having an increased risk of arterial stiffness was higher with high PM 10, PM 2.5, NO 2 in inactive subjects but not in physically active participants [57]. Other studies conducted on the risk of ischemic heart disease and stroke suggesting that physical activity may reduce PM 2.5 induced risk of cardiovascular events in subjects who are involved in physical activity above 2 times/week [58,59]. Studies conducted on animal models tried to investigate the protective role of physical activity against the harmful effects of air pollution.…”

Physical Activity in Polluted Air—Net Benefit or Harm to Cardiovascular Health? A Comprehensive Review

“…However, these increased risks were only present in subjects that exercised at most once a week and no interaction effect between physical activity and PM 2.5 exposure was found, suggesting that physical activity may reduce PM 2.5 induced risk of incident cardiovascular events. A further study by Raza et al, including 34,748 Swedish adults, confirmed these results by showing that being physically active at least twice a week was associated with decreased risk of incident ischemic heart disease among subjects exposed to high levels of PM 2.5 (HR 0.60, 95% CI 0.44–0.82) and PM 10 (HR 0.55, 95% CI 0.4–0.76) [ 106 ]. Conversely, this effect was weaker/not present among subjects exposed to low levels of PM 2.5 (HR 0.94, 95% CI 0.72–1.22) and PM 10 (HR 0.99, 95% CI 0.76–1.29).…”