Association between diurnal temperature range and outpatient visits for hand, foot, and mouth disease in Hefei, China: a distributed lag nonlinear analysis.

We aimed to quantify the relationship between the outpatient visits of hand, foot, and mouth disease (HFMD) and diurnal temperature range (DTR). The data of daily HFMD outpatient visits and meteorological parameters were obtained. A distributed lag nonlinear model combined with generalized linear model was used to estimate simultaneously nonlinear and delayed effects between DTR and daily HFMD outpatient visits after controlling confounding factors. A total of 15,275 HFMD visits were enrolled. DTR was significantly associated with HFMD outpatient visits in children. High DTR (P75: 11.4 °C) and extreme DTR (P95: 15.3 °C) were compared with 8.5 °C, and HFMD visits increased by a maximum of 3.93% (95% CI: 1.82 to 6.07%) and 4.47% (95% CI: 0.45 to 8.65%) in single-day lag effect, respectively. Furthermore, the extreme DTR effect decreased with the lag time and lasted for 10 days. Cumulative lag effects with markedly increasing percent of visits are over 64.88%. Furthermore, the effects were most pronounced among female children and children aged 0-2 years. Our study suggested that DTR changes were associated with HFMD outpatient visits, and populations of female and aged 0-2 years were more sensitive.