Interactions between cigarette smoking and ambient PM2.5 for cardiovascular mortality

Michelle C Turner; Aaron Cohen; Richard T Burnett; Michael Jerrett; W Ryan Diver; Susan M Gapstur; Daniel Krewski; Jonathan M Samet; C Arden Pope 3rd

doi:10.1016/j.envres.2017.01.024

Interactions between cigarette smoking and ambient PM_2.5 for cardiovascular mortality

Environ Res. 2017 Apr:154:304-310. doi: 10.1016/j.envres.2017.01.024. Epub 2017 Jan 28.

Authors

Michelle C Turner¹, Aaron Cohen², Richard T Burnett³, Michael Jerrett⁴, W Ryan Diver⁵, Susan M Gapstur⁵, Daniel Krewski⁶, Jonathan M Samet⁷, C Arden Pope 3rd⁸

Affiliations

¹ McLaughlin Centre for Population Health Risk Assessment, University of Ottawa, Ottawa, Canada; Barcelona Institute for Global Health (ISGlobal), Barcelona, Spain; Universitat Pompeu Fabra (UPF), Barcelona, Spain; CIBER Epidemiología y Salud Pública (CIBERESP), Madrid, Spain. Electronic address: mturner@uottawa.ca.
² Health Effects Institute, Boston, USA.
³ Population Studies Division, Health Canada, Ottawa, Canada.
⁴ Division of Environmental Health Sciences, School of Public Health, University of California Berkeley, Berkeley, USA; Department of Environmental Health Science, Fielding School of Public Health, University of California, Los Angeles, USA.
⁵ Epidemiology Research Program, American Cancer Society, Atlanta, GA, USA.
⁶ McLaughlin Centre for Population Health Risk Assessment, University of Ottawa, Ottawa, Canada; School of Epidemiology, Public Health and Disease Prevention, Faculty of Medicine, University of Ottawa, Ottawa, Canada.
⁷ Department of Preventive Medicine, Keck School of Medicine, USC Institute for Global Health, University of Southern California, Los Angeles, USA.
⁸ Department of Economics, Brigham Young University, Provo, USA.

PMID: 28142053
DOI: 10.1016/j.envres.2017.01.024

Abstract

Associations between long-term exposure to ambient fine particulate matter (PM_2.5) and all-cause and cardiovascular mortality are well documented however less is known regarding possible interactions with cigarette smoking. We previously reported a supra-additive synergistic relationship between PM_2.5 and cigarette smoking for lung cancer mortality. Here we examine interactions for all-cause and cardiovascular mortality among 429,406 current or never smoking participants in the prospective American Cancer Society Cancer Prevention Study-II with modeled PM_2.5 concentrations. Cox proportional and additive hazards models were used to estimate mortality associations and interactions on the multiplicative and additive scales. A total of 146,495 all-cause and 64,339 cardiovascular (plus diabetes) deaths were observed. The hazard ratio (HR) (95% confidence interval (CI)) for cardiovascular mortality for high vs. low PM_2.5 exposure (>14.44µg/m³ vs ≤10.59µg/m³, 75th vs 25th percentile) was 1.09 (95% CI 1.05, 1.12) in never smokers. The HR for cigarette smoking was 1.89 (95% CI 1.82, 1.96) in those with low PM_2.5. The HR for both high PM_2.5 and cigarette smoking was 2.08 (95% CI 2.00, 2.17). A small significant excess relative risk due to interaction (0.10; 95% CI 0.02, 0.19) was observed. Quantification of the public health burden attributed to the interaction between PM_2.5 and cigarette smoking indicated a total of 32 (95% CI -6, 71) additional cardiovascular deaths per 100,000 person-years due to this interaction. In conclusion, PM_2.5 was associated with all-cause and cardiovascular mortality in both smokers and never smokers, with some evidence for a small additive interaction with cigarette smoking. Reductions in cigarette smoking will result in the greatest impact on reducing all-cause and cardiovascular death at the levels of PM_2.5 observed in this study. However, reductions in PM_2.5 will also contribute to preventing a proportion of mortality attributed to cigarette smoking.

Keywords: Additive interaction; Air pollution; Cardiovascular mortality; Cigarette smoking; Particulate matter.

Publication types

Research Support, Non-U.S. Gov't

MeSH terms

Adult
Aged
Aged, 80 and over
Cardiovascular Diseases / epidemiology
Cardiovascular Diseases / etiology*
Cardiovascular Diseases / mortality*
Cohort Studies
Female
Humans
Male
Middle Aged
Particulate Matter / adverse effects*
Prospective Studies
Smoking / adverse effects*
United States / epidemiology

Substances

Particulate Matter

Grants and funding

CIHR/Canada