Non-optimal apparent temperatures can increase the risk of acne: a multi-center time-series study

As extreme temperature events increase globally, the influences of non-optimal temperature on health outcomes are of increasing concern. However, whether there is a correlation between non-optimal apparent temperature (AT) and acne is unknown. To illustrate the association between non-optimal AT and acne, data of daily acne outpatient visits, meteorological factors, and air pollutants from 2015 to 2019 in Chongqing, China were obtained. A multi-center study using distributed lag non-linear model (DLNM) was employed to explore the possible association between short-term non-optimal AT and outpatient visits for acne. Stratified analyses by age and gender were carried out to verify vulnerable populations. Results showed that both cold and hot AT were significantly associated with acne. The significant single-lag effects of cold AT lasted from lag0 to lag3, and cumulative-lag effects lasted from lag00 to lag07, with the highest relative risk of 1.09 (95%CI: 1.03-1.17) on lag0, and 1.34 (95%CI: 1.17-1.53) on lag07, respectively. In term of hot AT, the significant single-lag effects were observed from lag0 to lag3 with cumulative-lag effects from lag00 to lag07, with peak relative risk of 1.08 (95%CI: 1.02-1.14) on lag0 and 1.17 (95%CI: 1.08-1.27) on lag03, respectively. Stratified analyses showed that young patients (< 25 years old) and males were more susceptible to non-optimal AT. We provide the first evidence that non-optimal AT can increase the risk of acne, particularly for young people and males. Our findings add new sights regarding the potential adverse effects of non-optimal temperature on skin diseases especially acne.