Background: Numerous studies have explored the association of air pollution with asthma but have yielded conflicting results. The exact role of air pollution in the incidence of adult-onset asthma and whether this effect is modified by genetic risk, lifestyle, or their interaction remain uncertain.
Methods: We conducted a prospective cohort study on 298,738 participants (aged 37-73 years) registered in the UK Biobank. Cox proportional hazard models were used to evaluate the association of air pollution, including particulate matter (PM2.5, PMcoarse, and PM10), nitrogen dioxide (NO2), and nitrogen oxides (NOx), with asthma incidence. We constructed genetic risk and lifestyle scores, assessed whether the impact of air pollution on adult-onset asthma risk was modified by genetic susceptibility or lifestyle factors, and evaluated the identified interactions.
Results: We found that each interquartile range increase in annual concentrations of PM2.5, NO2, and NOx was related to 1.04 (95% confidence interval [CI]: 1.01, 1.08), 1.04 (95% CI: 1.00, 1.08), and 1.03 (95% CI: 1.00, 1.06) times the risk of adult-onset asthma, respectively. The size of the effect of air pollution was greater among subpopulations with low genetic risk or unfavorable lifestyles. We also identified an additive interaction effect of air pollution with lifestyle factors, but not with genetic risk, on the risk of adult-onset asthma.
Conclusion: Our analyses show that air pollution increases the risk of adult-onset asthma, but that the size of the effect is modified by lifestyle and genetic risk. These findings emphasize the need for integrated interventions for environmental pollution by the government as well as adherence to healthy lifestyles to prevent adult-onset asthma.
Keywords: Air pollution; Asthma; Genetic factors; Lifestyle.
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