Poor air quality linked to cardiac 'events,' heart disease patients unaware

Poor air quality with high levels of tiny pollution particles known as PM 2.5 are tied to a spike in emergency department visits for heart- and lung-related illnesses and stroke, a California study suggests.

However, a nationwide US survey finds that few heart patients are aware of air quality risks.

Based on analysis of areas affected by the intense 2015 California wildfire season, researchers found that within a day of residents being exposed to dense smoke, emergency room visits for heart attacks and other cardiac events and symptoms rose by 15 per cent overall, and 42 per cent among people over age 65.

Stroke and other cerebrovascular emergencies rose 17 per cent overall, and 22 per cent for older adults, the study team reports in the Journal of the American Heart Association.

“Unlike places that have chronic exposure to poor air quality where we can educate people about the health risks, wildfires happen at unexpected times,” said senior study author Ana Rappold of the US Environmental Protection Agency’s National Health and Environmental Effects Research Lab in Durham, North Carolina.

“Wildfires have become a leading cause of short-term exposure to polluted air,” she said adding, “It’s important to talk to people about how exposure to wildfire can impact their health.”

Large-scale wildfires are projected to increase through the end of the century in many areas, particularly in California, Rappold and her colleagues note in their report. Wildfire smoke contains several pollutants, including carbon monoxide, nitrogen dioxide and ash particles that have been associated with lung and heart problems.

It also contains tiny particles, smaller than 2.5 micrometers, that are produced by burning, such as in wildfires, indoor cooking fires and motor vehicle exhaust.

These particles are small enough to enter the bloodstream from the lungs and are linked to inflammation, heart rhythm disturbances and clotting issues, the authors write.

Rappold and colleagues analysed emergency room visits between May 1 and September 30, 2015 in eight northern and central California basins where fires covered more than 800,000 acres of land.

Based on data from the National Oceanic and Atmospheric Administration, the research team followed smoke plumes and particulate matter concentrations as they moved across the state. They also looked at emergency room data for diagnoses such as heart attack, angina, cardiac dysrhythmia, pulmonary embolism, stroke, asthma, COPD and pneumonia.

The researchers found 3,61,000 cardiovascular, 15,500 cerebrovascular and 2,30,000 respiratory diagnoses. Emergency room visits for heart issues were associated with wildfire smoke density for all adults and were more pronounced for those over age 65. Brain and lung issues were also more severe among older adults, especially on medium- and dense-smoke days.

“We have an aging population in this country with increasing obesity, diabetes and associated heart and lung diseases, and we have an increasing number of acres that burn every year,” said one of the study’s co-authors, Dr. Wayne Cascio, who directs the EPA National Health and Environmental Effects Research Lab.

“We also have an increasing number of people encroaching on acres that have a high likelihood of burning,” Cascio said adding.“That’s the perfect storm of increasing the number of people who are at risk for wildfire exposure.”

In future studies, the EPA team plans to look at how long wildfire smoke and particulate matter lingers in the air and causes health problems, as well as how these air pollution exposures affect healthcare expenses through programs such as Medicare.

They've also launched Smoke Sense, a mobile app that encourages people to submit information about wildfire exposures and their health and productivity.

“I tell my patients that if they have heart or lung disease, they need to be mindful about poor air quality and smoke from wildfires,” Cascio said. “Avoid them to the extent that you can and look at EPA resources or others to plan what else you should do.”

In a separate study by a team at the Centers for Disease Control and Prevention in Atlanta, researchers found that people with lung disease are more likely than those with heart diseases to be aware of the risks they face during poor air quality alerts.

The research team analyzed surveys of more than 12,000 US adults between 2014 and 2016. About half of participants were aware of air quality alerts, 27 per cent said they avoided busy roads to reduce their exposure and 3 per cent said they had talked with a health professional about ways to avoid exposure to air pollution. Compared to the other survey participants, awareness of air quality alerts was 11 per cent more common among people with asthma and avoidance of busy roads was 13 per cent more common. People with asthma were also five times more likely to have spoken with a doctor about avoiding pollution exposure.

“Targeted public health messages about air quality might raise awareness about alerts and motivate changes in behavior among those at risk during periods of unhealthy air quality,” said lead study author Maria Mirabelli of the CDC’s Asthma and Community Health Branch.

“Be aware of air quality alerts and discuss with a health professional the strategies to reduce air pollution exposure,” Mirabelli advised. “Avoid busy roads to reduce exposure when walking, biking or exercising outdoors.”