A time-series study on the association of ambient temperature with daily outpatient visits of eczema in Huizhou city

Abstract

Objective: To explore the impact of environmental temperature exposure on eczema visits. Methods: Eczema clinic data from January 1, 2016 to December 31, 2019 were collected from the Huizhou Dermatology Hospital, and data on meteorological factors (average daily temperature and relative humidity) for the same period were derived from 86 meteorological stations of the Guangdong Provincial Climate Center. A distributed lag nonlinear model (DLNM) was used to assess the lagged effect of environmental temperature exposure on eczema, and a natural smooth spline function was used to control the nonlinear confounding of humidity. Results: There were 254 053 eczema outpatient visits at the Huizhou Dermatology Hospital within four years, with an average of 173.89 visits per day. The relationship between daily average temperature and the number of visits was non-linear (U shape). The risk of eczema increased by 2.20% (1.19%-3.21%) for every 1 ℃ decrease for the low temperature, and increased by 2.35% (1.24%-3.5%) for every 1 ℃ increase for the high temperature. The effect of high temperature was greater than that of low temperature. In all cases, 1.60% (0.44%-2.68%) of eczema outpatient visits were attributed to low temperature and the attributable number was 4 065 (1 128-6 798), while 6.33% (1.40%-10.87%) of eczema outpatient visits were due to high temperature and the attributable number was 16 082 (3 557-27 616). Conclusion: Both high temperature and low temperature are associated with increased risk of eczema.