Evidence map›Paper›PMID 42104306›Full record

ArticleBMC public health2026

The impact of humidex on other infectious diarrhea: a study of seasonal heterogeneity and lagged effects using a distributed lag non-linear model.

Ruoyu Gui, Wei Zhou, Jinsong Deng, Leiyu Shi, Guangli Hu, Gang Sun, Yingrong Lao

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Article in BMC public health, 2026. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Not yet cited in PubMed.

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4 · The record

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5 · Who and what money

Authors and funding

7 authors.

Ruoyu Gui *Department of Health Management, School of Health Management, Southern Medical University, Guangzhou, 510515, China.
Wei Zhou *The Second Clinical College of Guangzhou University of Chinese Medicine, Guangzhou, 510120, China.
Jinsong DengLaboratories & Facilities Management Office, Southern Medical University, Guangzhou, 510515, China.
Leiyu ShiDepartment of Health Policy and Management, Bloomberg School of Public Health, Johns Hopkins University, Baltimore, MD, 21205, USA.
Guangli HuGraduate School of Southern Medical University, Guangzhou, 510515, China. 1051454700@qq.com.
Gang SunDepartment of Health Management, School of Health Management, Southern Medical University, Guangzhou, 510515, China. sunhoney163@163.com.
Yingrong LaoThe Second Clinical College of Guangzhou University of Chinese Medicine, Guangzhou, 510120, China. laoyingrong@qq.com.

Funding

Gu Zhishan Academic Inheritance Studio Project of Guangdong Provincial Hospital of Traditional Chinese Medicine [2014]89Philosophy and Social Sciences Planning Project of Guangdong Province GD23CGL11Project of Guangdong Provincial Administration of Traditional Chinese Medicine: Integrated Analysis and Applied Research Combining Five Circuits and Six Qi Theory, Epidemiology, and Meteorology on Infectious Disease Epidemic Trends in Guangdong Province 20211055Research Project of Guangdong Institute of Modern Hospital Management GDXDYGS2025041Science and Technology Planning Project of Guangdong Province 2021B1212100007Special Project on Teaching Reform Research and Practice in International Education of Southern Medical University 2024GJG003
6 · The paper itself

Abstract

objectiveGlobal climate changehas led to frequent extreme hot and humid events. The Humidex, as a comprehensive temperature and humidity indicator, is closely related to infectious diseases. Other infectious diarrhea is an important public health issue, but the expode-response relationship between it and Humidex, especially the seasonal effect modification and lag effect patterns, still lacks systematic research. This study aims to evaluate the impact of Humidex on the incidence of other infectious diarrhea and explore its seasonal heterogeneity and time lag effect.

methodsUsing daily OID case and meteorological data from Guangdong Province (2014-2023), a Distributed Lag Non-linear Model was applied to assess the cumulative effects of Humidex, adjusting for season, day of the week, and holidays. Analyses included establishing the overall exposure-response relationship, stratifying by warm (May-October) and cold (November-April) seasons to examine effect modification, and conducting sensitivity analyses to verify robustness.

resultsAt the extreme Humidex exposure level (P95, 42.27), the cumulative relative risk (CRR) for OID was 1.183 (95% CI: 1.057-1.323), indicating a significant 18.3% increase in risk, with an attributable fraction (AF) of 15.4%. Conversely, a protective effect was observed at the low Humidex level (P5, 11.3) (RR = 0.832, 95% CI: 0.748-0.926). Lag analysis at high Humidex levels (e.g., P75, P90) showed that the highest risk occurred within 0-2 days after exposure, indicating a short-term lag effect. Seasonal stratification revealed significant effect modification: during the cold season, extreme Humidex showed a protective effect (RR = 0.523, 95% CI: 0.319-0.856), while the effect was non-significant in the warm season (RR = 0.957, 95% CI: 0.880-1.040), with a seasonal effect ratio of 1.83. Sensitivity analyses confirmed the robustness of the findings to variations in lag periods and degrees of freedom for splines.

conclusionHumidex is significantly associated with OID incidence, showing a non-linear exposure-response relationship and clear seasonal effect modification. While extreme Humidex generally increases OID risk, anomalously high levels during the cold season exhibit a protective effect. These findings support the development of season-specific early warnings and targeted public health interventions based on the Humidex index.

Indexed as

DiarrheaHumiditySeasonsChinaClimate ChangeHumansIncidenceNonlinear DynamicsTemperatureDistributed Lag Non-linear Model (DLNM)HumidexOther Infectious Diarrhea (OID)Seasonal heterogeneity

Identifiers

PMID42104306
PMCPMC13326543

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Read under generation 80e0d062 · epoch 390. Bibliography from PubMed, PubMed Central and OpenAlex; grants from NIH RePORTER; trial links from ClinicalTrials.gov; estimates, votes and beliefs from the OpenQuestion graph.