The Sixteenth Conference of the International Society for Environmental Epidemiology (ISEE): Abstracts
During summer 2003 record high temperatures were observed across Europe and Italy was one of the most affected countries. The northeast of Italy was mostly hit by the heat wave due to the more extreme weather conditions reported in that area. A health impact assessment of heat waves was carried out in different locations; we report results from 3 major Italian cities: two in the north and one in the central part of Italy.
Daily excess mortality was defined as the difference between the number of deaths observed on a given day and the smoothed average of daily number of deaths of a given reference period ranging from 8 to 21 years, depending on availability of data in each study area. Excess mortality was estimated by cause of death (ICD IX), age, gender, and socio-economic status. General health status before death of each study subject was assessed through hospital admissions in the previous three years and then comorbid conditions were identified according to the methodology proposed by Elixhauser. Specific co-mormidity of subjects deceased during heat waves was compared with co-morbidity of reference subjects deceased during heat waves free summer times of 1999–2002 period. Conditional logistic regression models provided estimates of odds ratios.
A strong association between daily mortality and Humidex index (a combined index of temperature and humidity) was observed. In one city – located in the central part of Italy – excess mortality was observed throughout the summer, while in the northern cities excess was concentrated in the first part of August. During the whole period a total of 933 excess deaths have been observed in the first city (+20%), 598 in the second one (+23%), 502 in the last city (+30%).
Excess mortality increased dramatically with age, the greatest impact being observed in the over-85 age group. Age adjusted gender specific mortality revealed a two fold increase of risk of females. Observed excess mortality was mainly due to central nervous system, cardiovascular, respiratory, circulatory and metabolic\endocrine gland disorders. Arrhythmia, diabetes, renal failure and neurologic disorders were the co-morbid conditions responsible of the observed mortality risk increase in association to heat wave exposure.
These results put in evidence different susceptibility of sub-groups of population to heat waves and are in favour of the development of prevention/care programs.