Association Between Short-Term Exposure to PM_2.5and PM₁₀and Mortality in Susceptible Subgroups: A Multisite Case-Crossover Analysis of Individual Effect Modifiers

Abstract

We performed a multisite study to evaluate demographic and clinical conditions as potential modifiers of the particulate matter (PM)-mortality association. We selected 228,619 natural deaths of elderly persons (ages ≥65 years) that occurred in 12 Italian cities during the period 2006-2010. Individual data on causes of death, age, sex, location of death, and preexisting chronic and acute conditions from the previous 5 years' hospitalizations were collected. City-specific conditional logistic regression models were applied within the case-crossover "time-stratified" framework, followed by random-effects meta-analysis. Particulate matter less than or equal to 2.5 µm in aerodynamic diameter (PM2.5) and particulate matter less than or equal to 10 µm in aerodynamic diameter (PM10) were positively associated with natural mortality (1.05% and 0.74% increases in mortality risk for increments of 10 µg/m3 and 14.4 µg/m3, respectively), with greater effects being seen among older people, those dying out-of-hospital or during the warm season, and those affected by 2 or more chronic diseases. Limited associations were found among persons with no previous hospital admissions. Diabetes (1.98%, 95% confidence interval (CI): 0.54, 3.44) and cardiac arrhythmia (1.65%, 95% CI: 0.37, 2.95) increased risk of PM2.5-related mortality, while heart conduction disorders increased risk of mortality related to both PM2.5 (4.22%, 95% CI: 0.15, 8.46) and PM10 (4.19%, 95% CI: 0.38, 8.14). Among acute conditions, recent hospital discharge for heart failure modified the PM10-mortality association. The study found increases in natural mortality from PM exposure among people with chronic morbidity; diabetes and cardiac disorders were the main susceptibility factors.

Association of Short-term Exposure to Air Pollution With Mortality in Older Adults

“…Findings from this study are also consistent with the literature regarding the observed effect sizes of both PM 2.5 4,7,15,25–27 and ozone. 6,19,28,29 This study further demonstrates that in more recent years, during which air pollution concentrations have fallen, statistically significant associations between mortality and exposures to PM 2.5 and ozone persisted.…”

Higher health effects of ambient particles during the warm season: The role of infiltration factors

“…Atmospheric aerosol has been documented to cause increased mortality, morbidity, decreased lung function and other adverse effects upon health (Beelen et al, 2014;Raaschou-Nielsen et al, 2013) with greater effects on frailty and elderly people (Alessandrini et al, 2016). While a body of evidence has been accumulating over the last few decades especially in relation to cardiovascular and respiratory diseases, there is still considerable uncertainty about the mechanisms of action linked to the health effects and about which physical and/or chemical characteristics of particulate matter (PM) are most important as determinants of health (REVIHAAP, 2013;Kelly and Fussell, 2012;Brunekreef and Holgate, 2002;Harrison and Yin, 2000).…”

The Associations between Types of Ambient PM2.5 and Under-Five and Maternal Mortality in Africa

“…Moreover, it is also estimated that over 90% of the world’s population live in LMICs where the levels of air quality surpass that of the World Health Organization’s (WHO) air quality standards [3]; that is, the global no-threshold limit for daily (≤25 μg/m 3 ) and annual (≤10 μg/m 3 ) ambient PM 2.5 exposure [4]. In recent years, many studies have also focused on the association between PM 2.5 and all-cause mortality, mainly in high-income countries, with a positive relationship being found [5,6,7,8,9,10]. However, studies on PM 2.5 and mortality are still limited in low- and middle-income countries (LMICs), where the majority of under-five and maternal preventable deaths occur.…”