Does Temperature Modify the Association between Air Pollution and Mortality? A Multicity Case-Crossover Analysis in Italy

Department of Epidemiology, Rome E Health Authority, Rome, Italy.
American journal of epidemiology (Impact Factor: 5.23). 07/2008; 167(12):1476-85. DOI: 10.1093/aje/kwn074
Source: PubMed


Adverse health effects of particulate matter <10 microm in aerodynamic diameter (PM(10)) and high temperatures are well known, but the extent of their interaction on mortality is less clear. This paper describes effect modification of temperature in the PM(10)-mortality association and tests the hypothesis that higher PM(10) effects in summer are due to enhanced exposure to particles. All deaths of residents of nine Italian cities between 1997 and 2004 were selected. The case-crossover approach was adopted to estimate the effect of PM(10) on mortality by season and temperature level. Three strata of temperature corresponding to low, medium, and high "ventilation" were identified, and the interaction between PM(10) and temperature within each stratum was examined. Season and temperature levels strongly modified the PM(10)-mortality association: for a 10-microg/m(3) variation in PM(10), a 2.54% increase in risk of death in summer (95% confidence interval: 1.31, 3.78) compared with 0.20% (95% confidence interval: -0.08, 0.49) in winter. Analysis of the interaction between PM(10) and temperature within temperature strata resulted in positive but, in most cases, nonstatistically significant coefficients. The authors found much higher PM(10) effects on mortality during warmer days. The hypothesis that such an effect is attributable to enhanced exposure to particles in summer could not be rejected.

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Available from: Carlo A Perucci, Feb 02, 2015
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    • "Our study has several other strengths in addition to the repeated-measure study design over changing air pollution exposure scenarios, including the healthy background of the study participants to avoid confounding from traditional cardiovascular risk factors (e.g., obesity, smoking and disease status), the selected study periods in spring and autumn seasons with moderate weather conditions to avoid significant weather changes which may potentially confound the associations between air pollution and health observations (Stafoggia et al., 2008), and the use of different statistical models to test the consistency of the air Table 2 Estimated percent changes a with 95% confidence intervals in antioxidant enzymes associated with interquartile range increases in selected PM 2.5 constituents over different statistical models. "
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    ABSTRACT: The association of systemic antioxidant activity with ambient air pollution has been unclear. A panel of 40 healthy college students underwent repeated blood collection for 12 occasions under three exposure scenarios before and after relocating from a suburban area to an urban area in Beijing, China in 2010-2011. We measured various air pollutants including fine particles (PM2.5) and determined circulating levels of antioxidant enzymes extracellular superoxide dismutase (EC-SOD) and glutathione peroxidase 1 (GPX1) in the laboratory. An interquartile range increase of 63.4 μg/m(3) at 3-d PM2.5 moving average was associated with a 6.3% (95% CI: 0.6, 12.4) increase in EC-SOD and a 5.5% (95% CI: 1.3, 9.8) increase in GPX1. Several PM2.5 chemical constituents, including negative ions (nitrate and chloride) and metals (e.g., iron and strontium), were consistently associated with increases in EC-SOD and GPX1. Our results support activation of circulating antioxidant enzymes following exposure to particulate air pollution. Copyright © 2015 Elsevier Ltd. All rights reserved.
    Environmental Pollution 06/2015; DOI:10.1016/j.envpol.2015.06.002 · 4.14 Impact Factor
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    • "Temperature may act as an effect modifier, but this idea remains controversial (Hales et al., 2000; Katsouyanni et al., 1993; Roberts, 2004; Samet et al., 1998). However, in several recent studies, a significant interaction was detected (Park et al., 2011; Qian et al., 2008; Ren and Tong, 2006; Stafoggia et al., 2008). Season-specific approaches have also shown that the adverse effects of air pollution are more apparent in the warm season, although substantial variations have been observed across locations (Nawrot et al., 2007; Peng et al., 2005). "
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    ABSTRACT: Substantial epidemiologic literature has demonstrated the effects of air pollution and temperature on mortality. However, there is inconsistent evidence regarding the temperature modification effect on acute mortality due to air pollution. Herein, we investigated the effects of temperature on the relationship between air pollution and mortality due to non-accidental, cardiovascular, and respiratory death in seven cities in South Korea. We applied stratified time-series models to the data sets in order to examine whether the effects of particulate matter <10μm (PM10) on mortality were modified by temperature. The effect of PM10 on daily mortality was first quantified within different ranges of temperatures at each location using a time-series model, and then the estimates were pooled through a random-effects meta-analysis using the maximum likelihood method. From all the data sets, 828,787 non-accidental deaths were registered from 2000-2009. The highest overall risk between PM10 and non-accidental or cardiovascular mortality was observed on extremely hot days (daily mean temperature: >99th percentile) in individuals aged <65years. In those aged ≥65years, the highest overall risk between PM10 and non-accidental or cardiovascular mortality was observed on very hot days and not on extremely hot days (daily mean temperature: 95-99th percentile). There were strong harmful effects from PM10 on non-accidental mortality with the highest temperature range (>99th percentile) in men, with a very high temperature range (95-99th percentile) in women. Our findings showed that temperature can affect the relationship between the PM10 levels and cause-specific mortality. Moreover, the differences were apparent after considering the age and sex groups. Copyright © 2015 Elsevier B.V. All rights reserved.
    Science of The Total Environment 04/2015; 524-525C:376-383. DOI:10.1016/j.scitotenv.2015.03.137 · 4.10 Impact Factor
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    • "Fouillet et al. (2006) found that the excess risk of deaths linked to O 3 and temperature together during the August 2003 HW in France ranged from 10.6% in Le Havre to 174.7% in Paris. Stafoggia et al. (2008) estimated that a 10 μg/m 3 increase in PM 10 concentration results in a 2.54% and 0.20% rise in risk of death in summer and winter, respectively. "
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    ABSTRACT: Meteorological (T and RH values) and air pollution data (PM10, NO2 and O3 concentrations) observed in Athens, Thessaloniki and Volos were analyzed to assess the air quality and the thermal comfort conditions and to study their synergy, when extreme hot weather prevailed in Greece during the period 2001–2010. The identification of a heat wave day was based on the suggestion made by the IPCC to define an extreme weather event. According to it, a heat wave day is detected when the daily maximum hourly temperature value exceeds its 90th percentile. This temperature criterion was applied to the data recorded at the cities center. Air quality was assessed at three sites in Athens (city center, near the city center, suburb), at two sites in Thessaloniki (city center, suburb) and at one site in Volos (city center), while thermal comfort conditions were assessed at the cities center. Mean pollution levels during the heat wave days and the non-heat wave days were calculated in order to examine the impact of the extreme hot weather on air quality. For this purpose, the distributions of the common air quality index and the exceedances of the air quality standards in force during the heat wave days and the non-heat wave days were also studied. Additionally, the variation of the daily maximum hourly value of Thom's discomfort index was studied in order to investigate the effect of extreme hot weather on people's thermal comfort. Moreover, the values of the common air quality index and Thom's discomfort index were comparatively assessed so as to investigate their synergy under extreme hot weather.
    Atmospheric Research 01/2015; 152:4–13. DOI:10.1016/j.atmosres.2014.06.002 · 2.84 Impact Factor
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