Tetyana Kendzerska

Summary We assessed the relation between air pollution, weather, and adherence to positive airway pressure (PAP) therapy in a retrospective community‐based repeated‐measures study of adults with obstructive sleep apnea who purchased PAP devices from a registered provider between 2013 and 2017 (Ottawa, Ontario, Canada) and had at least one day of data. Daily PAP‐derived data, air pollution, and weather databases were linked using postal code. The exposures were mean nocturnal (8:00 p.m. to 8:00 a.m.) (i) residential concentrations of nitrogen dioxide (NO 2 ), fine particulate matter <=2.5 μm (PM 2.5 ), ozone (O 3 ), and Air Quality Health Index (AQHI), and (ii) temperature, relative humidity, and barometric pressure. Covariates in the main model were demographics, season, exposure year, and PAP therapy mode. We analysed 8148 adults (median age of 54 years and 61% men) and 2,071,588 days of data. Based on daily data, the median (interquartile range) daily PAP usage was 416 (323–487) min. Using mixed‐effect regression analyses to incorporate daily data and clustering by individuals, we found a statistically significant decrease in adherence for increased levels of NO 2 , PM 2.5 , and AQHI. The largest effect was for NO 2 : a decrease in daily PAP use while comparing the highest versus lowest quartiles (Qs) was 3.4 (95% confidence interval [CI] 2.8–3.9) min. Decreased PAP adherence was also associated with increased temperature (Q4 versus Q1: 2.6 [95% CI: 1.5–3.7] min) and decreased barometric pressure (Q1 versus Q4: 2.0 [95% CI 1.5–2.5] min). We observed modest but statistically significant acute effects of air pollution and weather on daily PAP adherence.