Active and passive smoking in relation to lung cancer incidence in the Women's Health Initiative Observational Study prospective cohort
A partir des données de la cohorte "Women's Health Initiative Observational Study" incluant 93 676 participantes âgées de 50 à 79 ans, cette étude prospective évalue l'association entre le tabagisme, passif et actif, et le risque de cancer du poumon
Background : Lung cancer is the leading cause of worldwide cancer deaths. While smoking is its leading risk factor, few prospective cohort studies have reported on the association of lung cancer with both active and passive smoking. This study aimed to determine the relationship between lung cancer incidence with both active and passive smoking (childhood, adult at home, and at work). Patients and Methods : The Women's Health Initiative Observational Study (WHI-OS) was a prospective cohort study conducted at 40 U.S. centers that enrolled postmenopausal women from 1993-1999. Among 93,676 multi-ethnic participants aged 50-79, 76,304 women with complete smoking and covariate data comprised the analytic cohort. Lung cancer incidence was calculated by Cox proportional hazards models, stratified by smoking status. Results : Over 10.5 mean follow-up years, 901 lung cancer cases were identified. Compared to never smokers, lung cancer incidence was much higher in current (HR 13.44, 95% CI 10.80-16.75) and former smokers (HR 4.20, 95% CI 3.48-5.08) in a dose-dependent manner. Current and former smokers had significantly increased risk for all lung cancer subtypes, particularly small cell and squamous cell carcinoma. Among never smokers, any passive smoking exposure (HR 0.88, 95% CI 0.52-1.49) did not significantly increase lung cancer risk. However, risk tended to be increased in never smokers with adult home passive smoking exposure >30 years, compared to never smokers with no adult home exposure (HR 1.61, 95% CI 1.00-2.58). Conclusions : In this prospective cohort of postmenopausal women, active smoking significantly increased risk of all lung cancer subtypes; current smokers had significantly increased risk compared to former smokers. Among never smokers, prolonged passive adult home exposure tended to increase lung cancer risk. These data support continued need for smoking prevention and cessation interventions, passive smoking research, and further study of lung cancer risk factors in addition to smoking.