Diurnal temperature range as a novel risk factor for COPD death

Background and objective: Although the relationship between day‐to‐day temperature changes and COPD mortality is well established, it is not known whether temperature variation within one day, that is diurnal temperature range (DTR), is a risk factor for acute COPD death, independent of the absolute temperature level. Methods: In a time‐series study, the relationship between DTR and daily COPD mortality between 2001 and 2004 in Shanghai, China was assessed. A semi‐parametric generalized additive model was used to allow for long‐term and seasonable trends in COPD mortality, as well as variation in air pollution and weather. Results: There was a significant association between DTR and daily COPD mortality. A 1°C increase in the 4‐day moving average for DTR corresponded to a 1.25% (95% confidence interval: 0.35–2.15) increase in COPD mortality. Conclusion: These findings suggest that DTR is a novel risk factor for acute COPD death.