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

- The humidity effect on childhood HFMD by a distributed lag non-linear analysis in rural and urban areas was first detected.
- Their study explored the effects of humidity on childhood HFMD at a daily scale using a time series analysis.
- This is the first paper to explore the relationship between humidity and HFMD by using the data of the peak period of incidence.

ObjectiveTo 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 designRetrospective ecological study.MethodsA 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.ResultsThe 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.ConclusionsThis 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.