Ambient Temperature and Outpatient Visits for Acute Exacerbation of Chronic Bronchitis in Shanghai: A Time Series Analysis

The association between ambient temperature and acute exacerbation of chronic bronchitis （AECB） was still unknown. Therefore, we performed an epidemiological study in a large hospital of Shanghai to explore the relationship about temperature and outpatient visit for AECB. We adopted a quasi-Poisson generalized additive models and distributed lag nonlinear models to estimate the accumulative effects of temperature on AECB across multiple days. We found significant non-linear effects of cold temperature on hospital visits for AECB, and the potential effect of cold temperature might last more than 2 weeks. The relative risks of extreme cold （first percentiles of temperature throughout the study period） and cold （10th percentile of temperature） temperature over lags 0-14 d were 2.98 [95% confidence intervals （CI）： 1.77, 5.04] and 1.63 （95% Ch 1.21, 2.19）, compared with the 25th percentile of temperature. However, we found no positive association between hospital visits and hot weather. This study showed that exposure to both extreme cold and cold temperatures were associated with increased outpatient visits for AECB in a large hospital of Shanghai.

Association between Ambient Air Pollution and Outpatient Visits for Acute Bronchitis in a Chinese City

Objective To investigate the short-term association between outdoor air pollution and outpatient visits for acute bronchitis,which is a rare subject of research in the mainland of China.Methods A time-series analysis was conducted to examine the association of outdoor air pollutants with hospital outpatient visits in Shanghai by using two-year daily data（2010-2011）.Results Outdoor air pollution was found to be associated with an increased risk of outpatient visits for acute bronchitis in Shanghai.The effect estimates of air pollutants varied with the lag structures of the concentrations of the pollutants.For lag06,a 10 μg/m3 increase in the concentrations of PM10,SO2,and NO2 corresponded to 0.94%（95% CI：0.83%,1.05%）,11.12%（95% CI：10.76%,11.48%）,and 4.84%（95% CI：4.49%,5.18%） increases in hospital visits for acute bronchitis,respectively.These associations appeared to be stronger in females（P〈0.05）.Between-age differences were significant for SO2（P〈0.05）,and between-season differences were also significant for SO2（P〈0.05）.Conclusion Our analyses have provided the first evidence that the current air pollution level in China has an effect on acute bronchitis and that the rationale for further limiting air pollution levels in Shanghai should be strengthened.