Blog | Tuesday, May 15, 2012

QD: News Every Day--30 minutes of secondhand smoke enough to affect blood vessel endothelium


Inhaling even low levels of lingering secondhand smoke for a short period produces signs of cardiovascular dysfunction among nonsmokers, according to small study that tested lower concentration levels than have been researched before.

The study involved 33 healthy nonsmokers with no known history of diabetes, heart or kidney disease. Researchers checked participants’ salivary cotinine level to confirm they had no evidence of smoke exposure leading up to the one-day study.

Participants ranging from 18 to 40 years old were then assigned to one of three exposure levels: filtered clean air, levels of smoke typically found in the homes of smokers or lingering in a restaurant, and levels expected in a smoky bar or casino. In a laboratory-type environment, filtered non-menthol cigarettes were smoked using a smoking machine, and the aged smoke was routed to participants in a measured way, allowing researchers to control the smoke concentration.

Results will appear in the May 22 issue of the Journal of the American College of Cardiology.

Vascular studies including testing brachial artery reactivity with ultrasound measurements were performed before and after exposure to secondhand smoke. The brachial artery didn't dilate optimally among those exposed to lingering secondhand smoke, suggesting the endothelium was not functioning as it should.

Risk factors for impaired vascular function including age, sex, body mass index, total cholesterol, baseline cotinine values, and baseline arterial diameter were not significantly related to absolute changes in endothelial in this healthy population.

Endothelial dysfunction has been linked to all phases of atherosclerosis, from its inception to cardiac events such as stroke or heart attack.

The authors called for clinicians to not only focus on asking patients if they smoke, but to ask whether they live with or are even occasionally around a smoker, even if they are not in the same room when smoking occurs. They also called for broader policies to ban public smoking.