Ambient temperature exposure and risk of outpatient visits for dermatologic diseases in Xinxiang, China: a time-series analysis

The effect of ambient temperature on dermatologic diseases has received widespread attention. Previous studies have shown that ambient temperature might affect specific dermatologic diseases, but results were inconsistent. This study aims to assess the short-term effect of ambient temperature on outpatient visits due to dermatologic diseases (DMs) in Xinxiang, China. Daily DMs outpatient visits, mean temperature, mean relative humidity, and air pollution data of Xinxiang were retrieved from January 1, 2015, to December 31, 2018. A distributed lag nonlinear model (DLNM) was applied to analyze the effect of ambient temperature on DMs outpatients. We controlled several potential confounding factors such as the long-term trend, public holiday, day of the week, humidity, and air pollutants (NO2, PM2.5). Finally, two more stratification analysis was conducted by age and gender. A total of 164,270 outpatients of DMs were enrolled during our study, and the daily mean visits were 113. The estimated effect of temperature on DMs was nonlinear. Heat temperature would exacerbate outpatients of dermatologic diseases. With a reference median temperature (17 °C), the effect of temperature on DMs was most pronounced at lag0-14; exposure to heat (32 °C, 99th) was associated with 1.565 (95% CI: 1.266-1.934) increased risk of outpatients for DMs. Stratification analysis showed that citizens of young ages were susceptive to heat; both genders had a similar relationship between temperature and DMs risk. This study highlights that ambient temperature was associated with DMs outpatients; heat temperature might aggravate DMs risk. The health hazards of heat temperature required more attention, and more effective prevention measurements should be designed and implemented to curb global warming.