The Effect of Cold Temperature on Increased Exacerbation of Chronic Obstructive Pulmonary Disease: A Nationwide Study

Ching-Min Tseng,Albert C Yang,Yung-Tai Chen,Shuo-Ming Ou,Shuu-Jiun Wang,Tzeng-Ji Chen,Diahn-Warng Perng,Yi-Han Hsiao,Szu-Yuan Li,Sudha Chaturvedi

doi:10.1371/journal.pone.0057066

Abstract

BackgroundSeasonal variations in the acute exacerbation of chronic obstructive pulmonary disease (COPD) have been reported. However, the influence of air temperature and other meteorological factors on COPD exacerbation remains unclear.MethodsNational Health Insurance registry data from January 1, 1999 to December 1, 2009 and meteorological variables from the Taiwan Central Weather Bureau for the same period were analyzed. A case-crossover study design was used to investigate the association between COPD exacerbation and meteorological variables.ResultsA total of 16,254 cases who suffered from COPD exacerbation were enrolled. We found that a 1°C decrease in air temperature was associated with a 0.8% increase in the exacerbation rate on event-days (95% confidence interval (CI), 1.015–1.138, p = 0.015). With a 5°C decrease in mean temperature, the cold temperature (28-day average temperature) had a long-term effect on the exacerbation of COPD (odds ratio (OR), 1.106, 95% CI 1.063–1.152, p<0.001). In addition, elderly patients and those who did not receive inhaled medication tended to suffer an exacerbation when the mean temperature dropped 5°C. Higher barometric pressure, more hours of sunshine, and lower humidity were associated with an increase in COPD exacerbation.ConclusionsThis study demonstrated the effect of cold temperatures on the COPD exacerbation rate. Elderly patients and those without inhaled medicine before the exacerbation event were affected significantly by lower mean temperatures. A more comprehensive program to prevent cold stress in COPD patients may lead to a reduction in the exacerbations rate of COPD.

Highlights

Exacerbation of chronic obstructive pulmonary disease (COPD), defined as an acute worsening of respiratory symptoms beyond the usual status [1], leads to a deterioration in lung function [2] and quality of life [3] and an increased risk of mortality [4]
COPD exacerbations are more frequent in the winter, it is unclear whether the season itself or the above-mentioned meteorological factors exert an influence on exacerbations
Demographics and meteorological variables A total of 18,454 cases of COPD exacerbation were identified in our study cohort during an 11-year period

Summary

Introduction

Exacerbation of chronic obstructive pulmonary disease (COPD), defined as an acute worsening of respiratory symptoms beyond the usual status [1], leads to a deterioration in lung function [2] and quality of life [3] and an increased risk of mortality [4]. Respiratory viral infections have seasonal variations and are more prevalent in the winter [8,9,10] Meteorological factors, such as temperature, humidity, wind speed, sunshine and rainfall tend to vary with different seasons. COPD exacerbations are more frequent in the winter, it is unclear whether the season itself or the above-mentioned meteorological factors exert an influence on exacerbations. Seasonal variations in the acute exacerbation of chronic obstructive pulmonary disease (COPD) have been reported. The influence of air temperature and other meteorological factors on COPD exacerbation remains unclear

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