Zhenyan Bo1, Yue Ma2, Zhaorui Chang3, Tao Zhang2, Fengfeng Liu3, Xing Zhao2, Lu Long2, Xiaowei Yi2, Xiong Xiao4, Zhongjie Li3. 1. Department of Epidemiology and Biostatistics, West China School of Public Health and West China Fourth Hospital, Sichuan University, Chengdu, China; Department of Pharmacy, West China Second University Hospital, Sichuan University, Chengdu, China. 2. Department of Epidemiology and Biostatistics, West China School of Public Health and West China Fourth Hospital, Sichuan University, Chengdu, China. 3. Division of Infectious Disease & Key Laboratory of Surveillance and Early Warning on Infectious Disease, Chinese Center for Disease Control and Prevention, Beijing, China. 4. Department of Epidemiology and Biostatistics, West China School of Public Health and West China Fourth Hospital, Sichuan University, Chengdu, China. Electronic address: xiaoxiong.scu@scu.edu.cn.
Abstract
BACKGROUND: Hand, foot, and mouth disease (HFMD) remains a serious health threat to young children in East and Southeast Asia. The humidity is crucial for the survival of enterovirus, but the evidence of the humidity-HFMD association is inconsistent. In this study we investigated the spatial heterogeneity of humidity-HFMD associations and related effect modifiers. METHODS: We retrieved the daily surveillance data of childhood HFMD counts and meteorological variables from 143 cities in mainland China between 2009 and 2014 and then adopted a three-stage time series analysis. We first fitted a common distributed lag nonlinear model (DLNM) for each of the 143 cities separately to obtain the city-specific estimates of humidity-HFMD association. Then, we pooled the city-specific estimates through multivariate meta-regression with city-level characteristics as potential effect modifiers to study the reasons for heterogeneity. Finally, we applied a region-specific analysis to verify our findings and to better visualize our results. RESULTS: We found that the overall pooled humidity-HFMD relationship was shown as an approximately U-shaped curve with substantial spatial heterogeneity (I2 = 77.8%). Taking the reference relative humidity as 70%, the minimum relative risk (RR) was obtained at 45% with a value of 0.83 (0.79, 0.87), while the maximum RR was found to be at both 20% and over 85% separately with a value of 1.10 (1.05, 1.15). The spatial heterogeneity can be well explained by the climatic, social characteristics and terrains among cities. The modification effects can be roughly classified into two types, including change in the overall slope and the shape of the curve. CONCLUSIONS: Due to substantial spatial heterogeneity, caution should be taken when interpreting the weather-HFMD association in a single-site study and to avoid generalizing its findings to another site. Our study also implied the existence of interactions among meteorological factors given that climatic factors can modify the weather-HFMD association.
BACKGROUND: Hand, foot, and mouth disease (HFMD) remains a serious health threat to young children in East and Southeast Asia. The humidity is crucial for the survival of enterovirus, but the evidence of the humidity-HFMD association is inconsistent. In this study we investigated the spatial heterogeneity of humidity-HFMD associations and related effect modifiers. METHODS: We retrieved the daily surveillance data of childhood HFMD counts and meteorological variables from 143 cities in mainland China between 2009 and 2014 and then adopted a three-stage time series analysis. We first fitted a common distributed lag nonlinear model (DLNM) for each of the 143 cities separately to obtain the city-specific estimates of humidity-HFMD association. Then, we pooled the city-specific estimates through multivariate meta-regression with city-level characteristics as potential effect modifiers to study the reasons for heterogeneity. Finally, we applied a region-specific analysis to verify our findings and to better visualize our results. RESULTS: We found that the overall pooled humidity-HFMD relationship was shown as an approximately U-shaped curve with substantial spatial heterogeneity (I2 = 77.8%). Taking the reference relative humidity as 70%, the minimum relative risk (RR) was obtained at 45% with a value of 0.83 (0.79, 0.87), while the maximum RR was found to be at both 20% and over 85% separately with a value of 1.10 (1.05, 1.15). The spatial heterogeneity can be well explained by the climatic, social characteristics and terrains among cities. The modification effects can be roughly classified into two types, including change in the overall slope and the shape of the curve. CONCLUSIONS: Due to substantial spatial heterogeneity, caution should be taken when interpreting the weather-HFMD association in a single-site study and to avoid generalizing its findings to another site. Our study also implied the existence of interactions among meteorological factors given that climatic factors can modify the weather-HFMD association.
Authors: Hongxia Peng; Zhenhua Chen; Lin Cai; Juan Liao; Ke Zheng; Shuo Li; Xueling Ren; Xiaoxia Duan; Xueqin Tang; Xiao Wang; Lu Long; Chunxia Yang Journal: BMC Public Health Date: 2022-05-17 Impact factor: 4.135
Authors: Suyan Yi; Hongwei Wang; Shengtian Yang; Ling Xie; Yibo Gao; Chen Ma Journal: Int J Environ Res Public Health Date: 2021-02-17 Impact factor: 3.390
Authors: Yibo Gao; Hongwei Wang; Suyan Yi; Deping Wang; Chen Ma; Bo Tan; Yiming Wei Journal: Int J Environ Res Public Health Date: 2021-05-05 Impact factor: 3.390