המידע באדיבות מדיקונטקסט
Last Updated: 2001-07-24 16:00:41 EDT (Reuters Health)
By Steven Reinberg
WESTPORT, CT (Reuters Health) – Passive smoking significantly reduces coronary flow velocity reserve (CFVR), impairing endothelial function in healthy nonsmokers, according to the results of a study by Japanese researchers reported in the July 25th issue of the Journal of the American Medical Association.
Dr. Hiroyuki Watanabe and colleagues, from Osaka City University Medical School, studied 30 healthy Japanese men, who were a mean of 27 years old. Of these subjects, 15 were nonsmokers and 15 were asymptomatic active smokers, the researchers report. The nonsmokers lived and worked in smoke-free environments.
For each subject, Dr. Watanabe's team calculated CFVR before and after 30-minute exposure to environmental tobacco smoke.
The researchers found that among nonsmokers CFVR was significantly higher than in active smokers before exposure to tobacco smoke (p = 0.02). However, after exposure to tobacco smoke CFVR did not differ between the nonsmokers and active smokers (p = 0.83), Dr. Watanabe's group notes.
The researchers therefore conclude that exposure to environmental tobacco smoke significantly reduces CFVR in nonsmokers (p = < 0.001).
"The present findings suggest that reduction of CFVR after passive smoking may be caused by endothelial dysfunction of the coronary circulation, an early process of atherosclerosis, and this change may be one reason why passive smoking is a risk factor for cardiac disease morbidity and mortality in nonsmokers," Dr. Watanabe and colleagues write.
The results of this study "add to the evidence suggesting that everyone should be protected from even short-term exposure to the toxins in secondhand smoke," Drs. Stanton A. Glantz and William W. Parmley from the University of California, San Francisco, comment in a JAMA editorial.
By reducing exposure to passive smoking, "not only will everyone breathe better, but they will also have healthier hearts," Drs. Glantz and Parmley add.
"This is a very important finding," Dr. Norman H. Edelman from the State University of New York at Stonybrook, told Reuters Health. Dr. Edelman, a consultant for scientific affairs for the American Lung Association, noted that "epidemiologic studies have shown that passive smoking is responsible for 35,000 to 50,000 cardiovascular deaths per year." This new report provides "biologic proof of the epidemiology, and gives further evidence to those who support making public places smoke-free."
-Westport Newsroom 203 319 2700