Exposure to low levels of lingering secondhand smoke was found to impair endothelial function after 30 minutes in the brachial artery, according to research published in the Journal of the American College of Cardiology.
Researchers exposed 33 nonsmokers (aged 18 to 40 years) to either one of two low levels of aged secondhand smoke or to conditioned filtered air for 30 minutes. Participants were healthy with no diabetes, hypertension, chronic respiratory disease, kidney disease, CAD, prior MI or HF. The researchers measured participants’ salivary cotinine level — a biomarker of recent smoking — to confirm they had no evidence of smoke exposure leading up to the 1-day study.
Researchers used a linear regression model for each of two increases of secondhand smoke by 100 mcg/m3 respirable suspended particles. The absolute maximal percent brachial artery flow-mediated dilation for each increase from conditioned filtered air was reduced by 0.67%. The researchers said they did not find a threshold for the effect of secondhand smoke on flow-mediated dilation.
Short-term exposure to low levels of secondhand smoke for 30 minutes resulted in a concentration-dependent decrease in endothelial function as measured by flow-mediated dilation.
“These findings have significant public health implications. We saw a steep decline in vascular function even after a very short exposure to low levels of secondhand smoke, and that’s very concerning,” said study researcher Paul F. Frey, MD, division of cardiology, San Francisco General Hospital. “Breathing in very low levels of secondhand smoke — the same amount many people and children would encounter out and about in the community — appears to impair one’s vascular function after just 30 minutes of exposure.”
Disclosure: Dr. Frey has received a postdoctoral research award for this study from the Tobacco-Related Disease Research Program. See the full study for the other researchers’ relationships relevant to this article.