Physical activity, sedentary behavior, and incidence of obstructive sleep apnea in three prospective US cohorts.

Reduced physical activity and increased sedentary behavior may independently contribute to development of obstructive sleep apnea (OSA) through increased adiposity, inflammation, insulin resistance and body fluid retention. However, epidemiologic evidence remains sparse, and is primarily limited to cross-sectional studies.We prospectively followed 50 332 women from the Nurses' Health Study (2002-2012), 68 265 women from the Nurses' Health Study II (1995-2013), and 19 320 men from the Health Professionals Follow-up Study (1996-2012). Recreational physical activity (quantified by metabolic equivalent of task [MET]-hours/week) and sitting time spent watching TV and at work/away from home were assessed by questionnaires every 2-4 years. Physician-diagnosed OSA was identified by validated self-report. Cox models were used to estimate hazard ratios (HRs) and 95% confidence intervals (CIs) for OSA incidence associated with physical activity and sedentary behavior.During 2 004 663 person-years of follow-up, we documented 8733 incident OSA cases. After adjusting for potential confounders, the pooled HR for OSA comparing participants with ≥36.0 versus <6.0 MET-hours/week of physical activity was 0.46 (95% CI: 0.43, 0.50; ptrend<0.001). Compared with participants spending <4.0 h/week sitting watching TV, the multivariable-adjusted HR (95% CI) was 1.78 (1.60, 1.98) for participants spending ≥28.0 h/week (ptrend<0.001). The comparable HR (95% CI) was 1.49 (1.38, 1.62) for sitting hours at work/away from home (ptrend<0.001). With additional adjustment for several metabolic factors including BMI and waist circumference, the associations with physical activity and sitting hours at work/away from home were attenuated but remained significant (ptrend<0.001), whereas the association with sitting hours watching TV was no longer statistically significant (ptrend=0.18).Higher levels of physical activity and fewer sedentary hours were associated with lower OSA incidence. The potential mediating role of metabolic factors in the association between sedentary behavior and OSA incidence may depend on type of sedentary behavior. Our results suggest that promoting an active lifestyle may reduce OSA incidence.