All over the world, in high-income and low-income countries, in communities large and small, urban and rural, air pollution is associated with an increased risk for cardiovascular disease.
Researchers working in 21 countries tracked levels of PM 2.5, particles of soot small enough to enter the lungs and pass into the bloodstream. The average level over the course of the study was 47.5 micrograms per cubic meter, well above the limit of 12 considered safe by the Environmental Protection Administration.
In the population the study followed — 157,436 people 35 to 70 years old — there were 9,152 fatal or nonfatal cardiovascular events during an average follow-up of nine years.
Each 10 microgram per cubic meter increase in PM 2.5 was associated with a 5 percent increase in the risk for any cardiovascular event, a 3 percent increased risk for heart attack, a 7 percent increased risk for stroke, and a 3 percent increased risk for cardiovascular death.
The researchers calculate that 14 percent of all cardiovascular events and more than 8 percent of cardiovascular deaths are attributable to air pollution.
“Air pollution is a major risk factor for cardiovascular disease globally,” said the lead author, Perry Hystad, an associate professor at Oregon State University. “There needs to be improvement, especially in developing countries, and even marginal decreases in air pollution make a big difference.”