Use of Air Filters associated with Improved Cardiovascular Health in Elderly

Researchers in Denmark have found that using high efficiency particle air (HEPA) filters significantly improved cardiovascular health in healthy, non-smoking elderly people, according to a recent study published in the American Journal of Respiratory and Critical Care Medicine. Doctors suggest that (HEPA) filters - along with weight loss, smoking cessation, and exercise - will become part of standard cardiovascular health.

The study sample consisted of 21 non-smoking couples aged 60-75 who lived near roads with heavy traffic. Researchers measured microvascular function (MVF) and ambient airborne particles in the participant's homes. For two 48-hour periods, the couples used an air purifier. During only one of the periods, the purifier was equipped with a HEPA filter. Since the participants did not know when the HEPA filter was attached, the researchers were able to use each couple as its own control. Throughout the study, the size distribution and number concentration of indoor air particles in each home were monitored.

A noninvasive finger sensor allowed researchers to analyze each participant's MVF. They also assessed biomarkers from blood and urine samples to look for markers of inflammation, hemostasis (halted bleeding), and oxidative stress (damage to cells caused by free radicals, for example).

The researchers found that "reduction of particle exposure by filtration of recirculated air for only 48 hours improved the microvascular function in healthy elderly citizens." These results suggest that "indoor air filtration represents a feasible means of reducing cardiovascular risk," according to Dr. Steffen Loft, coauthor of the study.

A key finding associated with a reduction of indoor air particles was a significant improvement in the function of small finger blood vessels. "This effect most likely indicates a general improvement in the function of the inner lining of small vessels, including those supplying the heart," said Dr. Loft. When the inner linking of small vessels is not functioning properly, people are at greater risk of dangerous or possibly fatal cardiovascular events.

The findings include:

* HEPA filtration removed about 60 percent of the ultrafine, fine and coarse air particles in homes
* HEPA filtration was associated with an 8.1 percent improvement in individual MVF.
* Secondary biomarkers from blood and urine were not significantly affected by HEPA filtration

"We expected that removing air particles with the HEPA filters would result in improvement of MVF but we were heartened and surprised by the extent it did, considering the modest levels of particles in the indoor air of the homes of the elderly," stated Dr. Loft. The authors maintain that further study is needed to determine the mechanisms underlying the improvement of MVF after filtration.

"The results of this study indicate that reduction of particles in recirculated indoor air by filtration significantly improves MVF in a healthy, non-smoking, elderly population," wrote Dr. Loft. "The improvement could not be ascribed to significant reduction in inflammation or oxidative stress by means of biomarkers."

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