Background: Ambient air pollution may affect the severity of untreated OSA, but it is unknown whether air pollution adversely impacts the effectiveness of positive airway pressure (PAP) therapy.
Research question: Do short-term changes in outdoor air pollution adversely impact adults with OSA using PAP therapy?
Study design and methods: We conducted a retrospective community-based repeated-measures longitudinal study of adults with OSA who purchased a PAP device from a registered equipment provider between 2013 and 2017 (Ontario, Canada) and had data on the daily device-derived residual apnea-hypopnea index (AHIFlow). We linked daily PAP-derived data to air pollution databases using postal codes. The primary exposures were mean nocturnal (8 pm to 8 am) residential concentrations of ozone, fine particulate matter, nitrogen dioxide, carbon monoxide, sulfur dioxide, and the Air Quality Health Index (AQHI). Potential confounders considered were demographics, season and year of exposure, initial OSA severity, other PAP parameters, and climate-related variables.
Results: Eight thousand one hundred forty-eight adults were analyzed with a median of 89 days (interquartile range [IQR], 29-302 days) of observation during which PAP was used for ≥ 4 h. The median daily AHIFlow was 1.2/h (IQR, 0.5-2.5/h). In mixed multivariate regression analyses, an increase in air pollution was associated with a statistically significant increase in AHIFlow for most statistical models. The largest effect was for the AQHI: an increase in AHIFlow while comparing highest vs lowest quartiles was 0.07/h (95% CI, 0.05-0.10/h).
Interpretation: We demonstrated a modest but statistically significant increase in residual respiratory events during PAP therapy associated with an increase in air pollution concentrations.
Keywords: OSA; air pollution; positive airway pressure therapy.
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