The Relationship between Occupation and Lung Cancer Incidence in the Women's Health Initiative Observational Study

Lung cancer remains the foremost cause of cancer mortality among US women, with a notable proportion arising in never-smokers. While occupational exposures contribute to lung cancer risk, women have been underrepresented in occupational studies. Therefore, we examined the relationship between occupational titles and lung cancer incidence in women, stratified by smoking exposure.

Postmenopausal women (N = 93,676) entered the Women's Health Initiative Observational Study prospective cohort beginning in 1993. Participants reported their three longest-held paid jobs at the study baseline and women were followed for health outcomes. Logistic regression models were used to estimate odds ratios (ORs) and 95% confidence intervals (CIs) for lung cancer incidence in association with ever working in a given occupation, as well as by employment duration (<10 years, ≥10 years), with adjustment for smoking, demographics, and lifestyle factors. Effect modification by smoking status was assessed in stratified models.

Higher lung cancer risks were observed among women employed in management, sales, food service, and personal care occupations, as well as for several less common occupations, including life sciences, museum-related technical roles, and farming, construction, and production jobs. For example, ever working as Archivists, Curators, and Museum Technicians was associated with higher risk (OR = 2.55; 95% CI: 1.22-5.32), as was employment in Farming, Fishing, and Forestry occupations (OR = 1.98; 95% CI: 1.11-3.55), compared to women who never worked in those jobs. Longer-duration employment (≥10 years) as Life Scientists was also associated with elevated risk (OR = 2.31; 95% CI: 1.19-4.49). Most associations did not differ significantly by smoking, or were stronger among never-smokers than smokers, suggesting potential occupational risks independent of smoking.

Occupational factors may increase women's lung cancer risk beyond smoking, necessitating targeted prevention and future research.