Short-term effects of air pollution on total and cardiovascular mortality - The confounding effect of influenza epidemics
ABSTRACT Air pollution is associated with total mortality. This association may be confounded by uncontrolled time-varying risk factors such as influenza epidemics.
We analyzed independent data on influenza epidemics from 7 European cities that also had data on mortality associated with particulates (PM10). We used 10 methods to control for epidemics (5 derived from influenza data and 5 from respiratory mortality series) and compared those results with analyses that did not control for these epidemics.
Adjustment for influenza epidemics increased the PM10 effect estimate in most cases (% change in the pooled regression coefficient: -1.9 to 38.9 for total mortality and 1.3 to 25.5 for cardiovascular mortality). A 10-microg/m increase in PM10 concentrations (lag 0-1) was associated with a 0.48% (95% confidence interval=0.27-0.70%) increase in daily mortality unadjusted for influenza epidemics, whereas under the various methods to control for epidemics the increase ranged from 0.45% (0.26-0.69%) to 0.67% (0.46-0.89%). The corresponding figures for cardiovascular mortality were 0.85% (0.53-1.18%) with no adjustment and from 0.86% (0.53-1.19%) to 1.06% (0.74-1.39%) with the methods of control.
The association between air pollution and mortality is not weakened by control for influenza epidemic irrespective of the method used. To adjust for influenza epidemics, one can use methods based on respiratory mortality counts instead of counts of influenza cases if the latter are not available. However, adjustment for influenza by any method tested did not markedly alter the air pollution effect estimate.
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ABSTRACT: We aimed to investigate the effects of ambient air pollutants on daily mortality in a relatively stable and homogeneous population in Guangzhou, China. Daily mortality, air pollution, and weather data between 2006 and 2009 were collected. The generalized additive model with poison regression was used to estimate the excessive risks (ERs) of air pollutants (PM10, SO2, and NO2) on total, cardiovascular and respiratory mortality. The effects of lag0–1 were the greatest for total non-accidental and cardiovascular deaths. The increments of 10μgm−3 in SO2, NO2, and PM10 were associated with ERs of 1.54% (95%CI: 1.03–2.06%), 1.42% (95%CI: 1.06–1.78%), and 1.26% (95%CI: 0.86–1.66%) respectively for total non-accidental deaths, and 2.28% (95%CI: 1.40–3.16%), 1.81% (95%CI: 1.20–2.41%), and 1.79% (95%CI: 1.11–2.47%) respectively for cardiovascular deaths. For persons who died from respiratory disease, however, the maximum effects occurred at lag0. The ERs for SO2, NO2, and PM10 were 1.36% (95%CI: 0.23–2.50%), 1.47% (95%CI: 0.66–2.29%) and 0.93% (95%CI: 0.03–1.83%), respectively. The effects of the three air pollutants on mortality were stronger in elderly and in women. The ERs in the present study were higher than those reported in Europe, the U.S., and most other Asian cities. Our findings show relatively higher ERs of daily mortality by ambient air pollutants in the center of Guangzhou, China, compared with estimates in other cities. Further studies with accurate exposure measurement among homogeneous population are needed to evaluate the precise magnitudes of the effects of the air pollutants.Atmospheric Environment 01/2012; 46. DOI:10.1016/j.atmosenv.2011.07.055 · 3.06 Impact Factor
Medecine et Longevite 09/2011; 3(3):103-103. DOI:10.1016/j.mlong.2011.09.001
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ABSTRACT: Dusts are one of the main air pollutants emitted during cement manufacturing. A substantial part of these are breathable particles that are less than 10μm in diameter (PM10), which represent a potential threat for the health of the exposed population. This study aimed at evaluating the short-term effects of PM10 concentrations on the health of children, aged 6-14 years, who attended the schools in Fumane (Italy), in proximity (1.2km) to a large cement plant. School absenteeism was used as a proxy indicator of child morbidity. Time series of daily school absences and PM10 concentrations were collected for 3 school-years from 2007 to 2010 (541 school-days, 462 children on average). The associations between PM10 concentrations and school absence rates in the same day (lag0) and in the following 4 days (lag1 to lag4) were evaluated using generalised additive models, smoothed for medium/long term trends and adjusted for day of the week, influenza outbreaks, daily temperature and rain precipitations. The average concentration of PM10 in the period was 34 (range: 4-183) μg/m(3). An average 10μg/m(3) increase of PM10 concentration in the previous days (lag0-4) was associated with a statistically significant 2.5% (95%CI: 1.1-4.0%) increase in the rate of school absences. The highest increase in the absence rates (2.4%; 95%CI: 1.2-3.5%) was found 2 days after exposure (lag2). These findings provide epidemiological evidence of the acute health effects of PM10 in areas with annual concentrations that are lower than the legal European Union limit of 40μg/m(3), and support the need to establish more restrictive legislative standards.International journal of hygiene and environmental health 08/2013; 217(2-3). DOI:10.1016/j.ijheh.2013.07.016 · 2.64 Impact Factor