Prospective cohort study of sex-specific associations between sleep apnea and lung cancer risk in patients with COPD

COPD is an established risk factor for lung cancer. Sleep apnea is prevalent among COPD patients, and the inflammation caused by intermittent hypoxemia may increase this lung cancer risk. Females have more systemic inflammation for a similar apnea-hypopnea index than males. A nationwide prospective study in Belgium investigated sex-specific assocations between sleep apnea and lung cancer risk among COPD patients aged ≥ 55 years. The study consisted of 62,903 COPD patients (42.8% female) of whom 2898 (4.60%) developed lung cancer. In a model adjusted for age, socioeconomic status, smoking status, alcoholism, frailty, comorbidities, and comedication was sleep apnea associated with increased lung cancer risk among female COPD patients (1545 versus 1350 per 100,000 person-years; aHR 1,31; 95% CI 1,05-1,63) and with decreased lung cancer risk among male COPD patients (1632 versus 2305 per 100,000 person-years; aHR 0,82; 95% CI 0,70-0,95). The impact of sleep apnea on lung cancer development was especially strong in female COPD patients with hypoxia-related comorbidities (aHR 2,65; 95% CI 1.11-6.34). The authors conclude that sleep apnea was associated with increased risk of lung cancer among female COPD patients and decreased risk of lung cancer among male COPD patients.