Analysis of the time-trend in the relationship between extremely heat temperatures and daily mortality from circulatory and respiratory causes in Castilla-La Mancha , Spain
The target population for the effects on health of heat temperatures (people older 65 years) is increasing. It is expected that the health effect of heat waves on daily mortality has increased in recent decades, particularly mortality from circulatory and respiratory causes. On the other hand, improvements in health care and socio-economic conditions should minimize this impact.To analyze the temporal evolution of the relationship between extremely high temperatures and daily mortality for circulatory and respiratory causes in Castile-La Mancha (CLM), area located in the center of Spain, in the period 1975-2008.
METHODS:
Series of daily mortality data for circulatory (ICD-10: I00-I99) and respiratory causes (ICD-10: J00-J99) in CLM between January 1, 1975 and December 31, 2008 were used. Data were provided by the National Statistics Institute. The daily maximum temperatures data correspond to Toledo observatory and was provided by AEMET. Three stages were differentiated 1975-1985, 1986-1996 and 1997-2008. Box-Jenkins models were performed to quantify the percentage increase (PI) in mortality for each degree in which the daily maximum temperature exceeds 37°C.
RESULTS:
For circulatory causes, there was a decreasing trend in PI in mortality with statistically significant association and. In the 1975-1985 period the PI was 18.2% (±4.1); in the 1986-1996 period was 16.1% (±2.6) and 5.8% (±2.3) in the 1997-2008 period. However, for respiratory causes there was an increasing trend with statistically significant association with high temperatures in PI. In the first period, the PI was 11.8%(±8.8); in the second period was 15.8%(±4.5) and in the last period the PI was 13.5%(±4.4).
CONCLUSIONS:
There is an increasing PI in respiratory mortality with statistically significant associations with the daily maximum temperature in the period 1975-2008 and a decreasing PI in cardiovascular mortality in the same period in CLM. Socio-economic and demographic variables might be involved in these results.