Assessment of temperature effect on childhood hand, foot and mouth disease incidence (0–5 years) and associated effect modifiers: A 17 cities study in Shandong Province, China, 2007–2012

Background Previous studies examining temperature–disease associations of hand, foot and mouth disease (HFMD) mainly focused on a single city. The results demonstrated great heterogeneity. A multi-city study is necessary to better understand temperature risk on the childhood incidence of HFMD and the associated modified factors. Objective To assess the effect of ambient temperature on childhood HFMD incidence and explore the potential associated effect modifiers in the study area. Methods Daily morbidity data and meteorological variables of the 17 cities were collected for the period from 2007 to 2012. Distributed lag non-linear model (DLNM) was used to estimate city-specific effects of temperature on HFMD incidence. A multivariate meta-analysis was then applied to pool the estimated city-specific effect. Potential effect modifiers were included in the multivariate meta-regression as meta-predictors. Results A total of 504,017 childhood HFMD cases were included in the study. The high-incidence period of HFMD was detected in late spring and early summer (April to June). The temperature–disease associations of the 17 cities demonstrated great heterogeneity and the pooled exposure–response curve was an approximately inverted V-shape. Regional indicator, numbers of healthcare institution and annual household income were considered as associated modifiers. Conclusion Our findings can provide a practical reference for the early warning and intervention strategies of HFMD. Different temperature–disease associations among different regions should be considered when formulating and optimizing public health policy.