Air pollution may raise mortality risk
In a study of more than 600 cities around the world, short-term exposure to air pollutants was linked to increased risks for all-cause, cardiovascular and respiratory mortality.
Using health and environmental data from the Multi-City Multi-Country (MCC) Collaborative Research Network database, Yuming Guo, MD, PhD, of the department of epidemiology and preventive medicine at Monash University in Melbourne, Australia, and colleagues assessed the association between inhalable particulate matter (PM10) and fine particulate matter (PM2.5) with daily all-cause, CV and respiratory mortality in 652 urban areas in 24 countries or regions from 1986 to 2015.
“The adverse health effects of short-term exposure to air pollution have been well documented and known to raise public health concerns of its toxicity and widespread exposure,” Guo said in a press release. “The smaller the airborne particles, the more easily they can penetrate deep into the lungs and absorb more toxic components causing death.”
The researchers included data on 59.6 million deaths, of which 20.1 million were attributable to CVD and 5.6 million were attributable to respiratory diseases. The average annual mean concentration of PM10 was 56 g/m3 in 598 cities and the annual mean concentration of PM2.5 was 35.6 g/m3 in 499 cities.
In pooled estimates, an average 10-g/m3 increase in 2-day moving average of PM10 concentration was linked to a 0.44% increase in daily all-cause mortality, a 0.36% increase in daily CV mortality and a 0.47% increase in respiratory mortality. Similarly, a 10-g/m3 increase in 2-day moving PM2.5 concentration was associated with a 0.68% increase in daily all-cause mortality, a 0.55% increase in daily CV mortality and a 0.74% increase in respiratory mortality.
Country-specific estimates for the change in daily all-cause mortality, however, varied widely, ranging from 0.3% in Colombia to 1.32% in Australia with increases in PM10 concentration and from 0.03% in Portugal to 2.54% in Greece with increases in PM2.5 concentration.
“Though concentrations of air pollution in Australia are lower than in other countries, the study found that Australians are more sensitive to particulate matter air pollution and cannot effectively resist its adverse impacts. This may be attributed to Australians’ physiological functions having adapted to living in areas with low levels of particulate matter air pollution,” Guo said.
Notably, the researchers also found stronger associations between PM10 and PM2.5 concentrations and all-cause mortality with lower annual concentrations of particulate matter and with higher annual temperatures (P < .001 for all comparisons).
In further analyses, the pooled concentration-response curves demonstrated a consistent increase in daily mortality as particulate matter concentration increased. Slopes also appeared steeper at lower concentrations and flatter at higher concentrations.
“In addition, positive associations were still detectable at levels below most global and regional air-quality guidelines or standards,” the researchers wrote. – by Melissa Foster
Disclosures: Guo reports he received grants from Career Development Fellowship of the Australian National Health and Medical Research Council. Please see the study for all other authors’ relevant financial disclosures.