Hourly differences in air pollution and risk of respiratory disease in the elderly: a time-stratified case-crossover study

Environmental Health

Research

Etsuji Suzuki¹  Takashi Yorifuji²  Saori Kashima³ 

[1] Department of Epidemiology, Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University, 2-5-1 Shikata-cho, 700-8558, Kita-ku, Okayama, Japan;Department of Human Ecology, Graduate School of Environmental and Life Science, Okayama University, 3-1-1 Tsushima-naka, 700-8530, Kita-ku, Okayama, Japan;Department of Public Health and Health Policy, Institute of Biomedical & Health Sciences, Hiroshima University, 1-2-3 Kasumi, 734-8551, Minami-ku, Hiroshima, Japan;

关键词: Air pollution;    Ozone;    Particulate matter;    Respiratory disease;    Short-term effect;    Sulfur dioxide;   

DOI  :  10.1186/1476-069X-13-67

 received in 2014-04-15, accepted in 2014-08-08,  发布年份 2014

来源: Springer

【 摘 要 】

BackgroundEpidemiological studies have shown adverse effects of short-term exposure to air pollution on respiratory disease outcomes; however, few studies examined this association on an hourly time scale. We evaluated the associations between hourly changes in air pollution and the risk of respiratory disease in the elderly, using the time of the emergency call as the disease onset for each case.MethodsWe used a time-stratified case-crossover design. Study participants were 6,925 residents of the city of Okayama, Japan, aged 65 or above who were taken to hospital emergency rooms between January 2006 and December 2010 for onset of respiratory disease. We calculated city-representative hourly average concentrations of air pollutants from several monitoring stations. By using conditional logistic regression models, we estimated odds ratios per interquartile-range increase in each pollutant by exposure period prior to emergency call, adjusting for hourly ambient temperature, hourly relative humidity, and weekly numbers of reported influenza cases aged ≥60.ResultsSuspended particulate matter (SPM) exposure 24 to <72 hours prior to the onset and ozone exposure 48 to <96 hours prior to the onset were associated with the increased risk of respiratory disease. For example, following one interquartile-range increase, odds ratios were 1.05 (95% confidence interval: 1.01, 1.09) for SPM exposure 24 to <48 hours prior to the onset and 1.13 (95% confidence interval: 1.04, 1.23) for ozone exposure 72 to <96 hours prior to the onset. Sulfur dioxide (SO2) exposure 0 to <24 hours prior to onset was associated with the increased risk of pneumonia and influenza: odds ratio was 1.07 per one interquartile-range increase (95% confidence interval: 1.00, 1.14). Elevated risk for pneumonia and influenza of SO2 was observed at shorter lags (i.e., 8–18 hours) than the elevated risks for respiratory disease of SPM or ozone. Overall, the effect estimates for chronic obstructive pulmonary disease and allied conditions were equivocal.ConclusionsThis study provides further evidence that hourly changes in air pollution exposure increase the risks of respiratory disease, and that SO2 may be related with more immediate onset of the disease than other pollutants.

【 授权许可】

CC BY   
© Yorifuji et al.; licensee BioMed Central Ltd. 2014