Is high relative humidity associated with childhood hand, foot, and mouth disease in rural and urban areas?

Abstract Objective To examine the relationship between relative humidity and childhood hand, foot and mouth disease (HFMD) in Hefei, China, and to explore whether the effect is different between urban and rural areas. Study design Retrospective ecological study. Methods A Poisson generalized linear model combined with a distributed lag non-linear model was used to examine the relationship between relative humidity and childhood HFMD in a temperate Chinese city during 2010–2012. Results The effect of relative humidity on childhood HFMD increased above a humidity of 84%, with a 0.34% (95% CI: 0.23%–0.45%) increase of childhood HFMD per 1% increment of relative humidity. Notably, urban children, male children, and children aged 0–4 years appeared to be more vulnerable to the effect of relative humidity on HFMD. Conclusions This article study indicates that high relative humidity may trigger childhood HFMD in a temperate area, Hefei, particularly for those who are young and from urban areas.