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Effect of High Temperature and Heat Waves in European Cities

Michelozzi, P*; D'Ippoliti, D*; Marino, C*; de'Donato, F*; Katsouyanni, K; Analitis, A; Biggeri, A; Baccini, M; Perucci, C A.*; Menne, B§

doi: 10.1097/01.ede.0000362882.19407.e3
Abstracts: ISEE 21st Annual Conference, Dublin, Ireland, August 25–29, 2009: Symposium Abstracts: Symposia Presentations

*Department of Epidemiology, Local health Authority Rome E, Rome, Italy; †Department of Hygiene, Epidemiology and Medical Statistics, Medical School, Athens University, Athens, Greece; ‡Department of Statistics G. Parenti, University of Florence, Florence, Italy; and §Global Change and Health, WHO Regional Office for Europe, Rome, Italy.

Abstracts published in Epidemiology have been reviewed by the organizations of Epidemiology. Affliate Societies at whose meetings the abstracts have been accepted for presentation. These abstracts have not undergone review by the Editorial Board of Epidemiology.


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Background and Objective:

Two multi-city projects funded by the European Union provided estimates of the impact of high temperature and heat waves on mortality and hospital admissions using an integrated and standardized approach: the PHEWE project (Assessment and Prevention of Acute Health Effects of Weather Conditions in Europe) and the EuroHEAT project (Improving Public Health Responses to extreme weather/heat-waves).

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The PHEWE study estimated the impact of high temperature on mortality and hospital admissions, in 15 cities (Athens, Barcelona, Budapest, Dublin, Helsinki, Ljubljana, London, Milan, Paris, Prague, Rome, Stockholm, Turin, Valencia, and Zurich). The EuroHEAT study, built upon the results and databases of the PHEWE project, was focused on the assessment of the effect of heat wave episodes on mortality in 9 cities (Athens, Barcelona, Budapest, London, Milan, Munich, Paris, Rome and Valencia). The two projects cover different periods (1990–2000 and 1990–2004, respectively).

In both studies, GEE models were used to estimate the impact of high temperature and heat wave episodes. Evaluation of the effect by sex and age group, and for specific causes of deaths/hospital admissions were performed. Results were pooled into two groups, Mediterranean and Northern-Continental cities.

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The two studies showed great heterogeneity in the thresholds level, in the impact of high temperature, and in the effect of heat waves episodes among the cities. The meta-analytic value of the threshold was 29.4°C for Mediterranean cities and about 6°C lower for North-continental cities. The increase in daily mortality for 1°C increase in temperature was greater in Mediterranean cities (+3.1%) than in Northern-Continental cities (+1.8%). The increment in daily mortality during heat waves was also greater in the Mediterranean cities (+21.8%) than in the North Continental cities (+12.4%). In most cities the risk of mortality was up to 3 times greater for heat waves of long duration and high intensity.

The greatest impact on mortality was observed during the 2003 heat wave, and the estimated effect ranged from (+105%) in Paris to +5.9% in Munich.

In both studies the largest effect was observed for respiratory mortality suggesting a specific effect of high temperature on the respiratory system.

Results confirmed an increasing effect by age, and in most of cities a greater susceptibility of females was observed.

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Results from these studies suggest that the effect of heat is heterogeneous among cities and it may be explained by the levels of exposure and by the different susceptibility of the resident population.

Public health interventions need to address these aspects in order to prevent a possible additional burden of disease during the summer season.

© 2009 Lippincott Williams & Wilkins, Inc.