Associations Between Air Temperature and Daily Suicide Counts in Astana, Kazakhstan

Abstract

Background and Objective. Seasonal variations in suicide mortality and its association with ambient air temperature have been observed in many countries. However, the evidence from Central Asia is scarce. The aim of the study was to assess the relationship between 4 indicators of air temperature and daily suicide counts in Astana, Kazakhstan. Material and Methods. The daily counts of suicides (ICD-10 codes, X60–X84) for the population of Astana in 2005–2010 were collected using death certificates and medical records at the Municipal Bureau of Forensic Medicine. Associations between the number of cases and mean, maximum, mean apparent, and maximum apparent temperatures were studied using negative binomial regression models controlling for the effects of month, year, weekends, holidays, wind velocity, barometric pressure, and relative humidity. Results. Altogether, there were 685 suicides in Astana in 2005–2010. A clear seasonal pattern with the peak in summer was observed. In crude analyses, significant associations between suicide counts and all 4 temperatures were found. After adjustment for other variables, only apparent temperatures remained significantly associated with the outcome. An increase in the mean apparent temperature by 1°C was associated with an increase in suicide counts by 2.1% (95% CI, 0.4–3.8). Similar results were obtained for the maximum apparent temperature (1.2%, 95% CI, 0.1–2.3). Conclusions. The results suggest a linear relationship between apparent temperatures and daily suicide counts across the whole spectrum of temperatures. Factors behind this association need further research with a further going aim to develop mitigation strategies in the period of climate change.