Studies examine pollution's cardiovascular effects
Home air purifiers had a positive impact on systolic blood pressure, and nighttime light might explain some of the association between air pollution and cardiovascular disease, recent studies showed.
Two studies examined associations between air pollution and cardiovascular disease (CVD).
In the first study, researchers looked at the effect of portable high-efficiency particulate air (HEPA) purifiers at home on systolic blood pressure (SBP) in adults with elevated baseline readings. The crossover trial randomized 154 adults living near highways to receive one month of either HEPA or sham filtration (the same HEPA units with the filter removed) in their homes, followed by a one-month washout period with no filtration and then the alternate treatment. Blood pressure measurements and participant questionnaires were collected at the start and end of each period. Results were published Aug. 6 by the Journal of the American College of Cardiology.
Participants with a baseline SBP greater than 120 mm Hg experienced an average 2.8 mm Hg reduction in SBP after one month of HEPA filtration (P=0.03). SBP increased by 0.2 mm Hg during a sham filtration period (P=0.85), resulting in a significant 3.0 mm Hg difference (P=0.04) in favor of HEPA filtration. There was no significant impact on diastolic blood pressure or among participants with a SBP below 120 mm Hg.
An editorial noted, “For decades there has been majority support for improving domestic air quality—which has directly led to sustained improvements in public health. However, the United States is currently at a major crossroads, with regulation of clean air and environmental protection under existential threat. As health care professionals, it is our obligation to educate the public about this issue and support policies to improve the health and wellbeing of our patients—and all Americans.”
In the second study, researchers considered the role of nighttime light and ambient air pollution in CVD risk. Researchers analyzed data from 416,032 participants in the UK Biobank whose exposure to nighttime light and air pollution was assessed using their addresses. Results appeared Aug. 6 in the Journal of the American Heart Association.
Individuals exposed to severe levels of air pollution had higher risk for coronary heart disease (hazard ratio [HR], 1.071; 95% CI, 1.022 to 1.121), heart failure (HR, 1.318; 95% CI, 1.218 to 1.427), arrhythmia (HR, 1.067; 95% CI, 1.016 to 1.121), all-cause CVD death (1.253; 95% CI, 1.117 to 1.406), and stroke (HR, 1.057; 95% CI, 1.005 to 1.111). Joint analysis of air pollution and nighttime light revealed a stepwise increase in CVD risk. Nighttime light mediated 24.80% of the effect of air pollution on coronary heart disease and between 20.04% and 39.24% of the effect on heart failure across exposure levels.
“These findings underscore the necessity of addressing both air pollution and [nighttime light] exposure simultaneously,” the authors wrote.