Effects of high temperature and high humidity exposure on hospitalization for circulatory system diseases and respiratory system diseases
GU Shaohua1, LU Beibei1, LU Wenhan2, Qiu Yidan1, Wang Yaqi1
1. Ningbo Center for Disease Control and Prevention, Ningbo, Zhejiang 315000, China; 2. Haishu District Meteorological Bureau, Ningbo, Zhejiang 315000, China
Abstract：Objective To assess the effects of combined high temperature and high humidity exposure on the risk of hospitalization for circulatory system diseases and respiratory system diseases. Methods Data on inpatients with circulatory system diseases and respiratory system diseases from 3 hospitals in the main urban area of Ningbo City, Zhejiang Province were collected for the periods of May to October in each year from 2022 to 2025, and the meteorological data of the same period were obtained from Ningbo Meteorological Service Center. A time-stratified case-crossover design was used to separately construct association models of daily mean temperature and wet-bulb globe temperature (WBGT) with the hospitalization counts of circulatory system diseases and respiratory system diseases. The optimal high temperature exposure assessment indicator was selected by comparing the model goodness-of-fit and the effect size of extreme high temperature (≥99th percentile). Exposure-response relationships between extreme high temperature and the risk of hospitalization for circulatory system diseases and respiratory system diseases were constructed using a temperature-humidity stratified interaction model, stratified by low and high relative humidity based on the 50th percentile. Results From May to October each year during 2022-2025, a total of 27 845 hospitalizations for circulatory system diseases and 27 023 hospitalizations for respiratory system diseases were recorded in Ningbo City. The median daily mean temperature and WBGT were 26.55 (interquartile range, 7.70) ℃ and 25.11 (interquartile range, 7.11) ℃, respectively. When WBGT was used as the exposure indicator, extreme high temperature exposure was positively associated with the hospitalization risks of circulatory system diseases (RR=1.192, 95%CI: 1.014-1.401) and respiratory system diseases (RR=1.278, 95%CI: 1.094-1.494). When daily mean temperature was used as the exposure indicator, extreme high temperature exposure was positively associated with the hospitalization risk of respiratory system diseases (RR=1.260, 95%CI: 1.080-1.471), while the association with the hospitalization risk of circulatory system diseases was not statistically significant (RR=1.146, 95%CI: 0.974-1.349). Considering that the quasi-Akaike information criterion value of this model was larger than that of the WBGT-based model, WBGT was selected as the optimal high temperature exposure assessment indicator. The temperature-humidity stratified interaction analysis showed that under high-humidity conditions, extreme high-temperature exposure was associated with higher risks of hospitalization for circulatory system diseases (RR=1.480, 95%CI: 1.000-2.192) and respiratory system diseases (RR=1.617, 95%CI: 1.102-2.374) in the overall population. Subgroup analysis showed that under high-humidity conditions, extreme high-temperature exposure was associated with higher risks of hospitalization for circulatory system diseases (RR=1.901, 95%CI: 1.187-3.044) and respiratory system diseases (RR=1.848, 95%CI: 1.074-3.179) among males, and with higher risk of hospitalization for respiratory system diseases among those aged 45-<65 years (RR=2.691, 95%CI: 1.127-6.426). Conclusion Combined exposure to high temperature and high humidity can increases the hospitalization risks of circulatory system diseases and respiratory system diseases, and males and the middle-aged population are susceptible high-risk populations.
谷少华, 陆蓓蓓, 鹿文涵, 裘一丹, 王亚奇. 高温高湿暴露对循环系统和呼吸系统疾病住院的影响[J]. 预防医学, 2026, 38(9): 880-885.
GU Shaohua, LU Beibei, LU Wenhan, Qiu Yidan, Wang Yaqi. Effects of high temperature and high humidity exposure on hospitalization for circulatory system diseases and respiratory system diseases. Preventive Medicine, 2026, 38(9): 880-885.
[1] Raymond C,Matthews T,Horton R M.The emergence of heat and humidity too severe for human tolerance[J/OL].Sci Adv,2020,6(19)[2026-09-06].https://doi.org/10.1126/sciadv.aaw1838. [2] He W Y,Chen H P.More extreme-heat occurrences related to humidity in China[J/OL].Atmos Ocean Sci Lett,2023,16(5)[2026-09-06].https://doi.org/10.1016/j.aosl.2023.100391. [3] Sobolewski A,Młynarczyk M,Konarska M,et al.The influence of air humidity on human heat stress in a hot environment[J].Int J Occup Saf Ergon,2021,27(1):226-236. [4] Armstrong B,Sera F,Vicedo-Cabrera A M,et al.The role of humidity in associations of high temperature with mortality:a multicountry,multicity study[J/OL].Environ Health Perspect,2019,127(9)[2026-09-06].https://doi.org/10.1289/EHP5430. [5] Fang W,Li Z X,Gao J H,et al.The joint and interaction effect of high temperature and humidity on mortality in China[J/OL].Environ Int,2023,171[2026-09-06].https://doi.org/10.1016/j.envint.2022.107669. [6] 谷少华,金永高,陆蓓蓓,等.2013—2018年宁波市高温热浪致超额死亡风险评价[J].预防医学,2021,33(9):897-901,905. [7] Tobias A,Kim Y,Madaniyazi L.Time-stratified case-crossover studies for aggregated data in environmental epidemiology:a tutorial[J/OL].Int J Epidemiol,2024,53(2)[2026-09-06].https://doi.org/10.1093/ije/dyae020. [8] Parsons K.Heat stress standard ISO 7243 and its global application[J].Ind Health,2006,44(3):368-379. [9] Liang C,Yuan J C,Tang X,et al.The influence of humid heat on morbidity of megacity Shanghai in China[J/OL].Environ Int,2024,183[2026-09-06].https://doi.org/10.1016/j.envint.2024.108424. [10] Gasparrini A,Armstrong B,Kenward M G.Distributed lag non-linear models[J].Stat Med,2010,29(21):2224-2234. [11] 李静,王焕新,屈龙,等.昌平区PM2.5和气温对日门诊量的交互影响[J].预防医学,2019,31(6):593-596,599. [12] 曾韦霖,马文军,刘涛,等.构建气温-死亡关系模型中温度指标的选择[J].中华预防医学杂志,2012,46(10):946-951. [13] Chen S J,Dong H,Li M M,et al.Interactive effects between temperature and PM2.5 on mortality:a study of varying coefficient distributed lag model-Guangzhou,Guangdong Province,China,2013-2020[J].China CDC Wkly,2022,4(26):570-576. [14] Cramer M N,Gagnon D,Laitano O,et al.Human temperature regulation under heat stress in health,disease,and injury[J].Physiol Rev,2022,102(4):1907-1989. [15] Wang W J,Wang J H,Song G H,et al.Environmental and sensitization variations among asthma and/or rhinitis patients between2008 and 2018 in China[J/OL].Clin Transl Allergy,2022,12(2)[2026-09-06].https://doi.org/10.1002/clt2.12116. [16] Rahman M M,McKeon K,Luglio D,et al.Compounding effects of heat and high humidity on cardiovascular morbidity in Dhaka,Bangladesh:an implication of climate crisis[J/OL].Sci Total Environ,2025,995[2026-09-06].https://doi.org/10.1016/j.scitotenv.2025.180220. [17] Baldwin J W,Benmarhnia T,Ebi K L,et al.Humidity's role in heat-related health outcomes:a heated debate[J/OL].Environ Health Perspect,2023,131(5)[2026-09-06].https://doi.org/10.1289/EHP11807. [18] 刘磊,宋丹丹,侯赛,等.2010—2016年安徽省高温中暑流行病学特征[J].疾病监测,2017,32(10):895-899. [19] 刘弢,李辉,张传会.某市2013至2017年高温中暑流行病学分析[J].中华劳动卫生职业病杂志,2018,36(12):915-916.
