No association between temperature and deaths from cardiovascular and cerebrovascular diseases during the cold season in Astana, Kazakhstan – the second coldest capital in the world

BACKGROUND Several European and North American studies have reported associations between cold temperatures and mortality from diseases of the circulatory system. However, the effects of cold vary between the settings warranting further research in other parts of the world. OBJECTIVES To study associations between temperature and mortality from selected diseases of circulatory system in Astana, Kazakhstan--the second coldest capital in the world. METHODS Daily counts of deaths from hypertensive diseases (ICD-10 codes: I10-I15), ischemic heart disease (I20-I25) and cerebrovascular diseases (I60-I69) among adults 18 years and older in Astana, Kazakhstan, during cold periods (October-March) in 2000-2001 and 2006-2010 were collected from the City Registry Office. Associations between mortality and mean apparent temperature and minimum apparent temperature (average for lags 0-15) were studied using Poisson regression controlling for barometric pressure (average for lags 0-3), wind speed and effects of month, year, weekends and holidays. Analyses were repeated using mean and minimum temperatures. RESULTS Overall, there were 320, 4468 and 2364 deaths from hypertensive disorders, ischemic heart disease and cerebrovascular diseases, respectively. No significant associations between either mean, mean apparent, minimum or minimum apparent temperatures were found for any of the studied outcomes. CONCLUSIONS Contrary to the European findings, we did not find inverse associations between apparent temperatures and mortality from cardiovascular or cerebrovascular causes. Factors behind the lack of association may be similar to those in urban settings in Siberia, that is, centrally heated houses and a culture of wearing large volumes of winter clothes outdoors. Further research on the sensitivity of the population in Kazakhstan to climatic factors and its adaptive capacity is warranted.