Abstract
Hand, foot and mouth disease (HFMD) is a common childhood infection and has become a major public health issue in China. Considerable research has focused on the role of meteorological factors such as temperature and relative humidity in HFMD development. However, no studies have specifically quantified the impact of another major environmental agent, excessive heat, on HFMD. The current study was designed to help address this research gap.
Case-based HFMD surveillance data and daily meteorological data collected between 2010 and 2012 was obtained from China CDC and the National Meteorological Information Center, respectively. Distributed lag nonlinear models were applied to assess the impact of excessive heat on HFMD and its variability across social-economic status and age groups.
After controlling the effects of several potential confounders, the commonly hot days were found to positively affect the HFMD burdens with the relative risk (RR) peaking at around 6days of lag. The RR of HFMD in the Pearl-River Delta Region was generally higher and persisted longer than that in the remaining developing areas. Regarding the inter-age group discrepancy, children aged 3–6years old had the highest risk of HFMD under conditions of excessive heat whereas those greater than 6years old had the lowest. The lag structure of the impact of the extremely hot days was quite similar to that of the commonly hot days, although the relative effect of these two kinds of conditions of excessive heat might vary across regions.
This study indicated significantly facilitating effects of excessive heat on HFMD especially among those aged 3–6 and from developed areas. Results from the current study were particularly practical and important for developing area-and-age-targeted control programs in the context of climate change and urbanization.
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•The facilitating effect of excessive heat on HFMD was verified and quantified.•The impact of excessive heat varied across socio-economic status and age groups.•RRs in developed areas were higher and persisted longer.•Children aged 3–6 were the most sensitive to excessive heat.•Relative effect of two kinds of conditions of excessive heat varied across regions.