Abstract
Background Associations between cold temperatures and mortality from respiratory diseases have been observed in many countries. Less is known about the effects of temperature on acute morbidity. Objectives To study associations between minimum apparent temperature and the number of ambulance calls for asthma in Astana, Kazakhstan during the cold season. Methods Daily counts of ambulance calls for asthma (ICD-10 code J45) for the population of Astana, Kazakhstan, for the cold seasons (1 October-31 March) during 2006-2010 were obtained from the Municipal Ambulance Station. Associations between the number of calls and minimum apparent temperature (average for lags 0-15) were studied using Poisson regression controlling for wind speed and effects of month, year, weekends and holidays. Analyses were performed separately for children and adults aged 18-44 years, 45-59 years and 60 years and older. Results Altogether, there were 7372 ambulance calls for asthma during cold seasons of 2006-2010. An inverse association between minimum apparent temperature and absolute counts of calls was observed for the age-group 60 years and older (3110 calls): decrease of temperature was associated with an increase in the number of calls by 1.7% (95% CI: 0.1%-3.3%) across the whole temperature spectrum. No associations between the temperature and the number of calls were found among other age-groups. Conclusions The results suggest an inverse association between the minimum apparent temperature and the number of ambulance calls for asthma during the cold season in Astana, Kazakhstan, but this is limited to the oldest age-group. Further research is needed to study sensitivity and adaptive capacity of this vulnerable group to develop strategies to mitigate the health risks related to climate change. Key message The results suggest an inverse association between the minimum apparent temperature and the number of ambulance calls for asthma during the cold season in Astana, Kazakhstan.