Association between ambient temperature and respiratory health

Background: Climate change has increased temperature variability, impacting respiratory health. While the data related to its short-term effects on lung function is conflicting, its long-term effects remain even more uncertain. Therefore, this study aimed to evaluate the short-, mid-, and long-term effects of ambient temperature on lung function and respiratory symptoms in a nationally representative population. Methods: We conducted a cross-sectional analysis of 10,819 participants from the Korean National Health and Nutrition Examination Survey (KNHANES) [2016-2018]. Individualised temperature exposures were estimated using high-resolution atmospheric models. Generalised additive model (GAM) and distributed lag non-linear model (DLNM) were used to assess the short-term (lag days 0-14), mid-term [moving average (MA): 30-180 days], and long-term (MA: 1-5 years) effects on lung function. Results: (-3.87%, 95% CI: -6.81% to -0.93%) at 13.7 ℃, relative to the MRT of 10.0 ℃, with a more pronounced effect at upper temperature extremes. Chronic sputum production was associated with long-term heat exposure [1-year, odds ratio (OR): 1.349, 95% CI: 1.173-1.554; 3-year, OR: 1.299, 95% CI: 1.093-1.552; 5-year, OR: 1.189, 95% CI: 1.000-1.423]. Conclusions: Short- and long-term heat exposure were associated with impaired lung function, with more pronounced effects observed at higher temperatures.