Effects of ambient temperature on outpatient visits for dermatitis in Xinxiang, China: a time-series analysis

Previous studies have reported regional variations in the relationship between ambient temperature and dermatitis, which therefore remain inconclusive. This study aimed to understand the short-term effects of ambient temperature in outpatients with dermatitis in Xinxiang. Routine data of dermatitis outpatient visits between January 1, 2015, and December 31, 2018 were acquired from the First Affiliated Hospital of Xinxiang Medical University. A distributed lag nonlinear model (DLNM) in combination with a generalized additive model (GAM) was applied to investigate the acute impact of ambient temperature on dermatitis outpatients. Two stratified analyses based on age and sex were conducted to explore their potential modification effects. A total of 18,064 dermatitis outpatient records were retrieved during the study period. The relationship between ambient temperature and dermatitis outpatients was found to be nonlinear; exposure-response curves were approximately "J" shaped. The risk of dermatitis outpatient increased with a corresponding elevation in temperature from 11.5 to 27.5°C. However, the significance was lost when the temperature exceeded the given range. Stratified analysis demonstrated higher sensitivity to temperature in females than in males, and the young groups (<15 years) might be sensitive to heat temperature. This study provides first-hand epidemiological evidence demonstrating a higher risk of dermatitis outpatient visits associated with moderately higher temperatures. The outcomes of this study create awareness among citizens to take the necessary precautions to prevent the adverse effects of moderate heat temperature during early summer and autumn seasons.