The effects of ambient temperature on outpatient visits for varicella and herpes zoster in Shanghai, China: a time-series study.

Abstract

The seasonality of varicella and herpes zoster has been widely observed, but there is limited evidence on their associations with ambient temperature. The associations between ambient temperature and outpatient visits for varicella and herpes zoster were examined. We collected daily outpatient visit data for varicella (N = 3520) and herpes zoster (N = 6614) from a major hospital in Shanghai, China, from 2008 to 2010. We adopted the generalized additive model in time-series analysis to investigate the short-term associations between temperature and outpatient visits for varicella and herpes zoster after controlling for seasonal trends, day of the week, and humidity. A 1°C increase in daily mean temperature was associated with a 1.33% (95% confidence interval 0.93%-1.74%) decrease in outpatient visits for varicella whereas it was associated with a 2.18% (95% confidence interval 1.90%-2.46%) increase in outpatient visits for herpes zoster. Only 1 hospital was included and we did not control for individual-level risk factors. Our results demonstrated that temperature variation might be an important risk factor for varicella and herpes zoster in China.