Long-term air pollution exposure tied to CV health risks
Long-term exposure to air pollution was associated with increased risk for acute MI, ischemic heart disease mortality and CVD mortality, with greater risk in communities with lower socioeconomic status, data from a retrospective study show.
In an analysis of more than 3 million adults in California using electronic health record data and geocoded location data, researchers also observed CV risk for people who were exposed to moderate concentrations of fine particulate air pollution (PM2.5) below the current U.S. regulatory standard of 12 g/m3.
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“Our study is one of the largest to date to look at the effects of long-term exposure to fine particulate air pollution PM2.5, and it clearly adds to the evidence that the current regulatory standards are not sufficient to protect public health,” Stacey E. Alexeeff, PhD, a research scientist and biostatistician at the Kaiser Permanente Northern California Division of Research, told Healio. “The strongest association between exposure to air pollution and risk for CV events in our study was seen among people who live in low socioeconomic areas. We definitely need to be concerned about how these multiple burdens of poverty and air pollution accumulate and affect heart health.”
Long-term pollution data
In a retrospective study, Alexeeff and colleagues evaluated the associations between long-term PM2.5 and CV events using EHRs from the Kaiser Permanente Northern California integrated health care system (2007-2016) and geocoded address data for 3.7 million adults (mean age, 41 years; 52.5% women; 50.2% white). Participants had no prior stroke or acute MI, lived in Northern California for at least 1 year and were followed for 10 years. Researchers updated individual-level time-varying 1-year mean PM2.5 exposures for every participant monthly from baseline through the end of follow-up, accounting for address changes.
“This study represents an important contribution to the field by extracting key information previously only available in smaller prospective cohort studies of air pollution: geocoded longitudinal residential address data and detailed health information on important confounders such as smoking status, BMI and comorbidity diagnoses,” the researchers wrote. “To our knowledge, this is the first U.S. study of long-term PM2.5 exposure and cardiovascular events that includes more than 1 million people with individual-level geocoded address data.”
The primary outcomes were incident acute MI, ischemic heart disease, mortality and CVD mortality. Researchers also assessed associations below the current federal regulation limit.
The findings were published in JAMA Network Open.
Researchers found that for each 10 g/m3 increase in 1-year mean PM2.5, there was a 12% increased risk for incident acute MI (95% CI, 7-18), a 21% increased risk for ischemic heart disease mortality (95% CI, 13-30) and an 8% increased risk for CVD mortality (95% CI, 3-13).
PM2.5 exposure at moderate concentrations, defined as 10 g/m3 to 11.9 g/m3, was associated with a 6% increased risk for incident acute MI (95% CI, 3-10) and a 7% increased risk for ischemic heart disease mortality (95% CI, 2-12) compared with low concentrations, defined as less than 8 g/m3, according to researchers.
“We found evidence of effect modification by neighborhood socioeconomic status for all outcomes, with larger PM2.5 associations among those living in low socioeconomic status neighborhoods compared with high socioeconomic status neighborhoods,” the researchers wrote. “In sensitivity analyses using neighborhood income, we found similar effect modification results for ischemic heart disease and CVD mortality, but no differences by neighborhood income for incident acute MI.”
The researchers noted that findings suggest the current regulatory standard of 12 g/m3 is not sufficiently protective of human health.
New pollution standards ‘may be needed’
“Our work has the potential to play an important role in ongoing national conversations led by the Environmental Protection Agency on whether — and how much — to tighten air quality standards to protect the public from pollution’s effects,” Alexeeff told Healio. “Specifically, our findings support the EPA’s analysis that lowering the annual standard to at least 10 micrograms per cubic meter is needed to protect the public, and our results also suggest that lowering the annual standard to 8 micrograms per cubic meter may be needed to reduce the risk of heart attacks. I am also concerned that there are areas in California that continue to have annual levels of particulate air pollution above the current standard of 12 micrograms per cubic meter, despite the regulations we currently have in place and what we know about the effects of pollution on heart health.”
For more information:
Stacey E. Alexeeff, PhD, can be reached at stacey.alexeeff@kp.org.
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