Chronic, long-term exposure to a radioactive property of fine particulate matter common with radon gas may drive CVD mortality, particularly from MI** and stroke, researchers reported.
The primary source of particle radioactivity in the U.S. is radon gas through its decay products, Shuxin Dong, SM, a doctoral student in population health sciences at Harvard T.H. Chan School of Public Health, and colleagues wrote. Once radon, a colorless and odorless noble gas, is formed, it migrates into the atmosphere, they wrote.
“We know that fine particulate matter (PM2.5) are very small particles in the air that can be inhaled and cause many health problems; however, little is known about which physical,
chemical or biological properties of PM fuel its toxicity,” Dong said in a press release. “We studied gross beta activity, a property of one particulate matter that is a result of radon that attaches to particles and makes them radioactive, resulting in particle radioactivity. When inhaled, these very small particles penetrate deeply into the lungs and enter the bloodstream and circulate throughout the body.”
Dong and colleagues analyzed death data from the Massachusetts Department of Health from 2001 to 2015; data included coordinates of the residential address, date of death, place of death and underlying cause. Researchers then converted residential address coordinates to the corresponding ZIP code tabulation areas and aggregated deaths for each cause by year and by
ZIP code tabulation area. Researchers analyzed the association between particle radioactivity, measured as gross beta activity from highly resolved spatiotemporal predictions, and mortality for CVD*, MI**, stroke and all-cause nonaccidental mortality. Analyses were also stratified by
age groups.
The findings were published in the Journal of the American Heart Association.
Researchers observed associations between gross beta activity and PM2.5 and each mortality cause. Using difference-in-differences and adjusting for PM2.5, researchers found the highest associations with MI (incidence rate ratio [IRR] = 1.16; 95% CI, 1.08-1.24) and stroke (IRR = 1.11; 95% CI, 1.04-1.18) for an interquartile range increase (0.055 millibecquerels per cubic meter) in gross beta activity.
The researchers also observed a positive interaction between PM2.5 and gross beta activity,
with higher associations between PM2.5 and mortality at a higher level of gross beta activity.
The associations varied across age groups.
“The risk of death from cardiovascular disease, heart attack or stroke and all causes due to PM was higher and, therefore, more toxic when gross beta-activity levels were higher,” Dong said in the release. “These findings suggest that particle radioactivity increases the risk of death from cardiovascular disease and enhances the damage from particulate matter. This must be further investigated and may lead to targeted, cost-effective air quality regulations.”
*CVD: Cardiovascular Disease
**MI: Myocardial infarction
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October 05, 2022
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