P II – 1–4 A time series analysis of associations between climate change and heat related illnesses and development of a heat health warning system in Thailand

Background/aim: Thailand has no heat health warning system.However, there is an increasing number of heat-related illnesses (HRI) yearly. Thus, the objective of this work was toinvestigate the statistical associations between climatic variablesand heat-related illnesses with an aim to set up a suitablethreshold level for Heat Health Warning System in Thailand. Methods: Daily HRI of hospital admissions from the ICD10database with diagnosis T67 (Effects of heat and light) werecollected between January 2010 to December 2014 from theBureau of Policy and Strategy, Department of Disease Control,Ministry of Public Health, Thailand. Daily temperature andhumidity from the same period were obtained from Meteorological Department Ministry of Digital Economy and Society.The heat index was calculated according to the Steadmanequation. Time series and Poisson regression analysis wereused to find out the relationship between HRI and heat indexcontrolling for day of the week and holiday indicator, for lagtimes of 1-7 days. Results: There were 6,895 HRI visits. The overall incidencewas 2.14 visits per 1 00 000 persons per year. The majorityof patients were female. The highest incidence was in the 80-84 years old group with an age-specific incidence rate of 7.21per 1 00 000 persons per year. The relative risks of HRI visitsin the country at 25th and 75th percentile of the mean of heat index at lag 0 were 31.44 and 42.53, respectively. Thein-country regional relative risks at the 25th percentile of theSouthern, Northern, Central and Northeast regions were 5.01,15.79, 55.37 and 26.38, respectively. Similarly, the relativerisks at the 75th percentile of Southern, Northern, Centraland Northeast regions were 5.56, 21.76, 79.59, and 39.75,respectively. Conclusion: The level of heat index has a positive associationwith heat-related illnesses visits. A suitable warning thresholdlevel of heat index for Thailand will be investigated in thenext stage of the study