Interactions between cigarette smoking and fine particulate matter in the Risk of Lung Cancer Mortality in Cancer Prevention Study II.
The International Agency for Research on Cancer recently classified outdoor air pollution and airborne particulate matter as carcinogenic to humans. However, there are gaps in the epidemiologic literature, including assessment of possible joint effects of cigarette smoking and fine particulate matter (particulate matter less than or equal to 2.5 µm in diameter) on lung cancer risk. We present estimates of interaction on the additive scale between these risk factors from Cancer Prevention Study II, a large prospective US cohort study of nearly 1.2 million participants recruited in 1982. Estimates of the relative excess risk of lung cancer mortality due to interaction, the attributable proportion due to interaction, and the synergy index were 2.19 (95% confidence interval (CI): -0.10, 4.83), 0.14 (95% CI: 0.00, 0.25), and 1.17 (95% CI: 1.00, 1.37), respectively, using the 25th and 75th percentiles as cutpoints for fine particulate matter. This suggests small increases in lung cancer risk among persons with both exposures beyond what would be expected from the sum of the effects of the individual exposures alone. Although reductions in cigarette smoking will achieve the greatest impact on lung cancer rates, these results suggest that attempted reductions in lung cancer risk through both tobacco control and air quality management may exceed expectations based on reducing exposure to either risk factor alone.
Michelle C
MC
Turner
Aaron
A
Cohen
Michael
M
Jerrett
Susan M
SM
Gapstur
W Ryan
WR
Diver
C Arden
CA
Pope
Daniel
D
Krewski
Bernardo S
BS
Beckerman
Jonathan M
JM
Samet
D000328:Adult; D000367:Age Factors; D000368:Aged; D000393:Air Pollutants / Q000633:toxicity*; D000397:Air Pollution / Q000009:adverse effects*; D004781:Environmental Exposure / Q000009:adverse effects*; D005260:Female; D006801:Humans; D008175:Lung Neoplasms / Q000139:chemically induced* / Q000401:mortality; D008297:Male; D008875:Middle Aged; D052638:Particulate Matter / Q000633:toxicity; D016016:Proportional Hazards Models; D011446:Prospective Studies; D044469:Racial Groups / Q000706:statistics & numerical data; D012307:Risk Factors; D012737:Sex Factors; D012907:Smoking / Q000009:adverse effects*; D016540:Smoking Cessation / Q000706:statistics & numerical data; D014028:Tobacco Smoke Pollution / Q000009:adverse effects
D000393:Air Pollutants; D052638:Particulate Matter; D014028:Tobacco Smoke Pollution
additive interaction; air pollution; cigarette smoking; lung cancer mortality; particulate matter