A time series study on the effects of heat on mortality and evaluation of heterogeneity into European and Eastern-Southern Mediterranean cities: results of EU CIRCE project.

BACKGROUND: The Mediterranean region is particularly vulnerable to the effect of summer temperature.Within the CIRCE project this time-series study aims to quantify for the first time the effect of summer temperature in Eastern-Southern Mediterranean cities and compared it with European cities around the Mediterranean basin, evaluating city characteristics that explain between-city heterogeneity. METHODS: The city-specific effect of maximum apparent temperature (Tappmax) was assessed by Generalized Estimation Equations, assuming a linear threshold model. Then, city-specific estimates were included in a random effect meta-regression analysis to investigate the effect modification by several city characteristics. RESULTS: Heterogeneity in the temperature-mortality relationship was observed among cities. Thresholds recorded higher values in the warmest cities of Tunis (35.5°C) and Tel-Aviv (32.8°C) while the effect of Tappmax above threshold was greater in the European cities. In Eastern-Southern Mediterranean cities a higher effect was observed among younger age groups (0-14 in Tunis and 15-64 in Tel-Aviv and Istanbul) in contrast with the European cities where the elderly population was more vulnerable. Climate conditions explained most of the observed heterogeneity and among socio-demographic and economic characteristics only health expenditure and unemployment rate were identified as effect modifiers. CONCLUSIONS: The high vulnerability observed in the young populations in Eastern-Southern Mediterranean cities represent a major public health problem. Considering the large political and economic changes occurring in this region as well future temperature increase due to climate change, it is important to strengthen research and public health efforts in these Mediterranean countries.

Short-term effects of summer temperatures on mortality in Portugal: a time-series analysis.

Heat stress is a current public health concern during the warm months in many urban areas. Climate change and increasing urbanization are expected to worsen this concern, with some locations being more vulnerable than others. The aim of this study was to determine the short-term effect of heat on mortality in the two most populated cities in Portugal: Lisbon and Oporto. Each city was assessed for specific heat stress threshold above which heat-related mortality becomes significant. A Poisson generalized estimating equations (GEE) model was used to estimate the impact of maximum apparent temperature (ATmax) and maximum temperature (Tmax) on daily mortality, in the summer season. Data show ATmax thresholds of 30.4°C for Lisbon and 26.3°C for Oporto, and Tmax thresholds of 29.3°C and 25.0°C, respectively. For every 1°C elevation in ATmax above the city-specific threshold, all-cause mortality rate rose by 7.13% (95% CI: 5.9; 8.4) in Lisbon and 4.31% (95% CI: 3.2; 5.4) in Oporto. The Tmax threshold increases were 5.6% (95% CI: 4.6; 6.6) in Lisbon and 3% (95% CI: 2.0, 3.9) in Oporto. In both cities, stronger associations were found for respiratory diseases and the elderly group was the most vulnerable. This study confirmed that elevated temperatures have a considerable impact on daily mortality frequency in the two most urbanized areas in Portugal. Our results also provide useful data for policymakers to better prepare local actions to mitigate and reduce the health risks associated with high temperatures.

Short-term effect of fine particulate matter (PM2.5) and ozone on daily mortality in Lisbon, Portugal.

INTRODUCTION: Urban ambient air pollution exposures continue to be a global public health concern. Although air quality targets are often exceeded in Lisbon, the largest city in Portugal, there is currently no study that has assessed the quantitative impact of these pollutants on daily mortality. MATERIALS AND METHOD: In this study, we conduct a time series analysis using generalized additive modeling to determine the exposure-response effect from ambient ozone (O(3)) and fine particulate matter (PM(2.5)) concentrations on daily mortality in Lisbon. The dataset used was limited to the Lisbon municipality and for the period 2004-2006. RESULTS AND CONCLUSION: For PM(2.5) exposures, we found that the relative risk for cardiovascular mortality in the population group ≥ 65 years is 2.39% (95%C.I. 1.29%, 3.50%) for each 10 µg/m(3) increase. A statistically significant cause-effect relationship for PM(2.5) and mortality was not observed in other population groups. We also report O(3) exposures to be associated with an increase of 1.11% (95%C.I. (0.58, 1.64)) for all-cause mortality in the population group ≥ 65 years and an increase of 0.96% (95%C.I. (0.56, 1.35)) for the general population. When analyzing by cause of death, our results showed a stronger association between O(3) exposure and cardiovascular mortality.

Short-term association between exposure to ozone and mortality in Oporto, Portugal.

Exposures to air pollution in developed countries have generally decreased over the last two decades. However, many recent epidemiological studies have consistently shown positive associations between low-level exposure to air pollutants and health outcomes. In Portugal, very few studies have analysed the acute effect of air pollutants on health. The present study evaluates the association between exposure to air pollution and daily mortality in the Oporto Metropolitan Area, Portugal. Generalised additive models were used for this analysis. Pollutants assessed were ozone, nitrogen dioxide, and particulate matter (PM(10)). Models were adjusted for time trend, seasonality, and weather. We report that an increase of 10 µg/m(3) in the daily ozone 8-h maximum moving-average corresponds to an increase of 0.95% (95%CI: 0.30, 1.60) and 1.58% (95%CI: 0.45, 2.73) in non-accidental mortality and cardiovascular mortality, respectively, in the summer season. A significant effect of 0.67% (95% CI: 0.03:1.32) was also found for the association between PM(10) and non-accidental mortality in the summer season. Associations with ozone and PM(10) exposures were higher in the elderly people. No significant effects on mortality were observed during the summer season with nitrogen dioxide exposures. Our analyses provide the first significant evidence in Oporto that exposures to O(3) and PM(10) have adverse effects on the health of the general population in the summer months.

Effects of apparent temperature on daily mortality in Lisbon and Oporto, Portugal.

BACKGROUND: Evidence that elevated temperatures can lead to increased mortality is well documented, with population vulnerability being location specific. However, very few studies have been conducted that assess the effects of temperature on daily mortality in urban areas in Portugal. METHODS: In this paper time-series analysis was used to model the relationship between mean apparent temperature and daily mortality during the warm season (April to September) in the two largest urban areas in Portugal: Lisbon and Oporto. We used generalized additive Poisson regression models, adjusted for day of week and season. RESULTS: Our results show that in Lisbon, a 1 degrees C increase in mean apparent temperature is associated with a 2.1% (95%CI: 1.6, 2.5), 2.4% (95%CI: 1.7, 3.1) and 1.7% (95%CI: 0.1, 3.4) increase in all-causes, cardiovascular, and respiratory mortality, respectively. In Oporto the increase was 1.5% (95%CI: 1.0, 1.9), 2.1% (95%CI: 1.3, 2.9) and 2.7% (95%CI: 1.2, 4.3) respectively. In both cities, this increase was greater for the group >65 years. CONCLUSION: Even without extremes in apparent temperature, we observed an association between temperature and daily mortality in Portugal. Additional research is needed to allow for better assessment of vulnerability within populations in Portugal in order to develop more effective heat-related morbidity and mortality public health programs.

National assessment of human health effects of climate change in Portugal: approach and key findings.

In this study we investigated the potential impact of climate change in Portugal on heat-related mortality, air pollution-related health effects, and selected vectorborne diseases. The assessment used climate scenarios from two regional climate models for a range of future time periods. The annual heat-related death rates in Lisbon may increase from between 5.4 and 6 per 100,000 in 1980-1998 to between 8.5 and 12.1 by the 2020s and to a maximum of 29.5 by the 2050s, if no adaptations occur. The projected warmer and more variable weather may result in better dispersion of nitrogen dioxide levels in winter, whereas the higher temperatures may reduce air quality during the warmer months by increasing tropospheric ozone levels. We estimated the future risk of zoonoses using ecologic scenarios to describe future changes in vectors and parasites. Malaria and schistosomiasis, which are currently not endemic in Portugal, are more sensitive to the introduction of infected vectors than to temperature changes. Higher temperatures may increase the transmission risk of zoonoses that are currently endemic to Portugal, such as leishmaniasis, Lyme disease, and Mediterranean spotted fever.