Physical activity and lung cancer risk in men and women

Purpose Although evidence has accumulated that recreational physical activities (PA) may reduce lung cancer risk, there is little evidence concerning the possible role of a potentially more important source of PA, namely occupational PA. We investigated both recreational and lifetime occupational PA in relation to lung cancer risk in a population-based case-control study in Montreal, Canada (N-CASES = 727; N-CONTROLS = 1,351). Methods Unconditional logistic regression was used to estimate odds ratios (OR), separately for men and women, adjusting for smoking, exposure to occupational carcinogens, and sociodemographic and lifestyle factors. Results In both sexes, increasing recreational PA was associated with a lower lung cancer risk (ORMEN = 0.66, 95% confidence interval (CI) 0.47-0.92; ORWOMEN = 0.55, 95% CI 0.34-0.88, comparing the highest versus lowest tertiles). For occupational PA, no association was observed among women, while increasing occupational PA was associated with increased risk among men (ORMEN = 1.96, 95% CI 1.27-3.01). ORs were not modified by occupational lung carcinogen exposure, body mass index, and smoking level; results were similar across lung cancer histological types. Conclusions Our results support the previous findings for recreational PA and lung cancer risk. Unexpectedly, our findings suggest a positive association for occupational PA; this requires replication and more detailed investigation.