Air pollution increases deaths associated with smoking

Smokers have a higher risk of dying from cardiovascular disease when exposed to higher levels of air pollution. This was the conclusion of a study from ISGlobal, which analysed the effects of exposure to fine particulate matter (PM 2.5) in smokers and non-smokers.

The authors of the study published in the journal Environmental Research explain that their earlier research had demonstrated a supra-additive relationship between PM 2.5 and cigarette smoking for lung cancer mortality. The aim of the recent study was to establish whether the combination of both of these exposures increases cardiovascular mortality.

This study is based on data relating to almost half a million American smokers and never smokers aged 30 years or older who took part in the American Cancer Society's Cancer Prevention Study-II.

ISGlobal researcher Michelle C. Turner—first author of the study—explains the conclusion: “adding the risk of air pollution to that of smoking increases the risk of dying from cardiovascular disease and diabetes, although the supra-additive effect is smaller than in the case of lung cancer”.

The authors estimated that 318 cardiovascular and diabetes deaths for every 100,000 person-years are attributable to smoking and 36 to higher exposure to PM 2.5. An additional 32 deaths were estimated to be due to the interaction between smoking and PM 2.5.

Turner considers that “with the levels of PM 2.5 observed in this study, a reduction in smoking would have a greater positive impact on mortality than a reduction in exposure to air pollution”. However, a reduction in PM 2.5 would nonetheless contribute to preventing some of the mortality attributed to cigarette smoking.

Reference

Turner MC, Cohen A, Burnett RT, Jerrett M, Diver WR, Gapstur SM, Krewski D, Samet JM, Pope CA III. Interactions between cigarette smoking and ambient PM2.5 for cardiovascular mortality. Environ Res. 2017 Apr;154:304-310. doi: 10.1016/j.envres.2017.01.024.