Air pollution exposure may help forecast death risk: study

Environmental factors such as air pollution may help predict people’s chances of dying — particularly from conditions like heart attack and stroke, a new study has found.

Exposure to above average levels of outdoor air pollution increased risk of death by 20 percent and increased risk of death from cardiovascular disease specifically by 17 percent, in a widespread survey published in PLoS One on Friday.

The use of wood- or kerosene-burning stoves for cooking and heat homes without proper ventilation increased death risk by 23 percent and 9 percent respectively — raising the specific risk of death by cardiovascular disease by 36 percent and 19 percent, the study determined. 

To arrive at these figures, researchers from the NYU Grossman School of Medicine and the Icahn School of Medicine at Mount Sinai combed through personal and environmental health data from 50,045 rural villagers in northeast Iran.

All study participants — most of whom were poor residents of Iran’s Golestan region — were over the age of 40 and agreed to have their health monitored during annual visits that began as far back as 2004, the researchers said.

Within the group, there were more than 2,700 cardiovascular deaths and 6,000 all-cause deaths during a 10-year follow-up period, according to the study.

Using data from NASA alongside geographical information systems technologies, the researchers mapped out eight environmental risk factors across Golestan: fine particulate pollution; household cooking, heating and ventilation; proximity to traffic; distances from sites that perform coronary intervention; socioeconomics; population density; land type; and nighttime brightness.

The scientists determined which environmental factors posed the most threat by combining them into a single model and controlling for interactions between them, lead author Michael Hadley, a fellow in cardiology and incoming assistant professor of medicine at Mount Sinai, explained in a statement.

They found that unlike air pollution, some of the other factors included in the analysis — such as population density, nighttime light and neighborhood income levels — were not independent predictors of death risk, the authors said in a second news release.

Compared with residents who had easier access to specialized medical services, those living farther away from clinics equipped with catheterization labs — capable of unblocking arteries — incurred a 1-percent increased risk of death for every 10 kilometers (6.2 miles) of distance, the study found.

In Golestan, most people live more than 50 miles away from such facilities, the authors noted.

Living within about 0.06 miles of a small roadway and 0.25 of a large highway was linked to a 13-percent increased risk in all-cause mortality, according to the study.

Unique from traditional studies on environmental risk, these findings offer evidence from individuals in low- and middle-income areas, the scientists noted. Most such previous research has focused on urban populations in high-income countries, with accessible healthcare services, according to the authors.

“These results illustrate a new opportunity for health policymakers to reduce the burden of disease in their communities by mitigating the impact of environmental risk factors like air pollution on cardiovascular health,” Hadley said.