Ozone air pollution and daily mortality in Genoa, Italy between 1993 and 1996

The association between ozone (O-3) and daily mortality was investigated in Genoa, an Italian city characterized by a Mediterranean climate and a high prevalence of elderly inhabitants. The O-3 effect, adjusted for long time trend, seasonality and weather, was assessed using Poisson regression modelling, allowing for overdispersion and autocorretation, and expressed as mean variation percent of daily mortality per 50 mu g/m(3) increase (MV). Significant MVs for overall (+4.0%) and cardiovascular (+7.2%) mortality were detected at I-day tag. The effects were stronger in the warmer season (May-October). Similar estimates were found after restricting the analyses to the elderly (>= 75 years). Furthermore, in this group, higher MVs were observed for total mortality at 2-day tag. A statistically significant synergistic effect between 03 and temperature was observed for cardiovascular mortality, particularly in elderly people, with an evident increase in mortality risk above 26 degrees C (MV + 30.0% for the whole population and +40.0% for the elderly, respectively). This investigation highlights the importance of taking local climatic and demographic features into account when comparing different time-series studies, and substantiates the influence of photochemical pollution on mortality trends in small urban areas. (c) 2005 The Royal Institute of Public Health. Published by Elsevier Ltd. All rights reserved.