Daily Mortality in the Autonomous Community of Madrid during the period 1986-1991 in the 45-64 age group: its relationship with Temperature

Abstract

Background: There are many types of work which relate mortality with different environmental factors. These focus on the general population or in the over-65 age-group, but are relatively few in those with reference to the 45-64 age group in which mortality has a large economic and social impact. The object of the present article is to analyse the existant association between daily mortality, from both diverse specific causes, as well as the air temperature in this group in Madrid. Madrid´s extreme climatic characteristics make this work of special interest. Methods: The ARIMA model was used according to the Box-Jenkins methodology for the infiltration of the daily series of mortality regarding temperature. Amongst the residuals, interrelated functions were established which establish an association between series eliminating communal seasonal factors as well as determining the length of disequilibrium between thermal extremes and excesses in mortality. Results: There is a V-shaped relationship between total daily mortality and temperature. The minimum mortality rate is established at a maximum daily temperature of 330C. Excess mortality is 0,8% for each degree below 330C, while that for each degree above is 3,0%. The functions of interrelated correlation indicate that this association is clear in males regarding general mortality as well as for circulatory diseases. In the case of high temperature the effect is immediate, while in lower temperatures we have to add a delay of 10-13 days. Conclusion: There is a significant statistical association between mortality and temperature extremes in people of this age group. Lost life expectancy indicates the extent of the problem and the need to implement preventative measures.