Nationwide Study of the Association between Temperature Variability and Sleep Apnea, and the Modifying Role of Air Pollution, in a Moderate-to-Severe Risk OSA Population

Obstructive sleep apnea (OSA) is a severe sleep disorder that is associated with various health complications. Despite previous research investigating the impact of ambient temperature on the severity of OSA, the potential influence of temperature variability (TV) remains underexplored. We used a nationwide data set among wearable smart device users to assess the association between TV and OSA severity in a population at moderate-to-severe risk of OSA. A case time series statistical method was used to assess the associations between TV and the risk of OSA exacerbation, apnea-hypopnea index (AHI), and mean oxygen saturation (SpO₂). Additionally, we explored the interaction of TV and air pollution with OSA severity. A total of 52,752 participants with 6,349,414 days of monitoring were finally included in the study. A 1 °C increase in TV₀₁ was associated with an increase of 0.92% (95%CI: 0.69, 1.15%) in excess risk of OSA exacerbation, increases of 0.046 events/h (95%CI: 0.036, 0.057) in AHI, and a decrease of 0.0064% (95%CI: 0.0059, 0.0068%) in SpO₂. We observed a significant synergistic interaction of TV and air pollution on the OSA severity. This study highlights that TV may exacerbate the severity of OSA, and air pollution can synergistically interact with TV to impact the OSA severity.