In another study on the effects of second-hand smoke, Japanese researchers sought to determine if short-term exposure to environmental tobacco smoke affected free-radical production in young, healthy nonsmokers.
Increasing evidence shows that second-hand smoke breaks down the antioxidant defenses, which is associated with impairment of the endothelial-dependent function of arterial walls. Endothelial dysfunction is an early feature of atherosclerosis, the disease process that underlies heart disease and stroke, and is an important marker of vascular damage.
Free-radicals, which are unstable molecules produced during a process called oxidation, can damage cells in the body. This damage is often called oxidative stress. It is significantly higher in children exposed to second-hand smoke.
To measure oxidation injury, the Austrian researchers examined levels of a biological compound called 8-epi-PGF2alpha in the blood and urine of 158 children (71 boys, 87 girls) ages 3 to 15. The compound is formed when free radicals attack arachidonic acid, a chemical whose normal function includes blood vessel dilation, blood clot prevention and inflammation reaction.
"It is a very potent blood vessel constrictor and may help create blood vessel spasm and set the stage for blood clot formation," says senior researcher Helmut F. Sinzinger, M.D., of the University of Vienna in Austria.
Children were grouped according to the smoking levels of their parents, whether both parents were smoking at home, and according to the number of cigarettes smoked each day. Researchers compared results to those from a nonsmoking control group.