Effects of Climate Variations on Hand-Foot-Mouth Disease in Ho Chi Minh City

Abnormal emergence of epidemics has been believed to be one of the most significant effects of climate change on human health, especially in the tropical zone. Hand-foot-mouth disease (HFMD) which possibly related to climatic changes has emerged in Vietnam since 2003. Ho Chi Minh City (HCMC) is particularly a Southern city with the highest cases and mortality numbers of HFMD in the whole country. Therefore, we conducted a retrospective observational study to analyse the association between climate variations and HFMD in HCMC. HFMD and meteorological data from 2010 to 2014 were collected from The Preventive Medicine Centre of HCMC and Sub-Institute of Hydrometeorology and Environment of South Vietnam. The research used time-series analysis and Poisson regression model to analyse the effects of climate fluctuations on HFMD, adjusting for seasonal and trend effects, lag effects and degrees of freedom. The research findings showed that climate variables (average temperature, average humidity, minimum humidity, precipitation, and the Southern Oscillation Index (SOI) daily data) had a significant influence on HFMD. Noticeably, the effects of climate variations on HFMD were considerable in children aged 1-3 and 3-5 years. The maximum lag effects were 3 weeks for temperature and humidity, 4 weeks for precipitation, and 6 weeks for SOI. Specifically, the relative risk of HFMD increased by 7.2 % for every 1°C increase in temperature, 6.75 % for every 1 % increase in humidity, 6.32 % for every 5 mm increase in precipitation, 4.42 % for every 5 units increase in SOI. The study provided a quantitative evidence that the increase of HFMD was significantly affected by the increase of climate variations. Therefore, the study provided the foundation for developing theory that is used in models and, ultimately, for making forecasts about future impacts of HFMD associated with climatic changes.