In regions with frequent heat waves, the relative risk of hand, foot, and mouth disease at the 95th temperature percentile was 3.17 compared to lower risk areas.
Do environmental factors modify the spatial heterogeneity in the temperature-HFMD association among children in western China?
Environmental factors such as extreme temperatures, air pollution, and vegetation index significantly modify the spatial heterogeneity of temperature-related HFMD risk in children.
Absolute Event Rate: 0% vs 0%
While meteorological and socioeconomic factors are well-documented modifiers of spatial heterogeneity in temperature–hand, foot, and mouth disease (HFMD) associations, substantial unexplained heterogeneity remains. This study investigates underexplored environmental modifiers—including extreme temperature events (heat waves and cold spells), air pollution, and normalized difference vegetation index (NDVI)—by analyzing 484,928 HFMD cases among children under six years old in western China (2013–2019) using distributed lag nonlinear models and meta-regression. We found that cold spells (accounted for 3.84% of the spatial heterogeneity attributable above the baseline level), PM 2.5 (3.06%), heat waves (2.72%), PM 10 (2.08%), NDVI (1.57%) and O 3 (0.78%) were statistically significant modifiers of spatial heterogeneity in the temperature-HFMD associations. Further analysis of PM 2.5 components identified nitrate (1.78%) and ammonium (1.58%) as additional modifiers. Among these, cold spells, heat waves, PM 2.5 , and NDVI were the primary contributors. Specifically, the relative risk ( RR ) of HFMD at the 95th temperature percentile reached 3.17 (95% CI: 2.39–4.19) in frequent heat waves regions and 3.05 (2.35–3.95) in high-PM 2.5 areas. Conversely, regions with low cold-spell frequency also exhibited increased temperature-related risk ( RR = 3.13, 2.40–4.07) at the same temperature, as did low NDVI regions ( RR = 2.16, 1.79–2.59). Spatial cluster analysis further revealed that the central and northeastern regions exhibited higher temperature-related HFMD risks compared to the southwestern region. These pronounced spatial modification effects challenge the generalizability of single-site study and highlight the importance of region-specific public health strategies that integrate early warning systems for extreme temperatures, air pollution mitigation, and locally adapted greening interventions.
Sun et al. (Fri,) reported a other. In regions with frequent heat waves, the relative risk of hand, foot, and mouth disease at the 95th temperature percentile was 3.17 compared to lower risk areas.