Q: My wife keeps nagging me about smoking in the house. She says it is my decision whether to kill myself by smoking cigarettes, but smoking in the house endangers her and our children. Is she right?
A: Experts now generally agree that significant health risks are associated with second-hand or passive smoking, that is, inhaling other people's tobacco smoke.
Recent estimates suggest that passive smoking is responsible for about 50,000 deaths annually among American non-smokers.
Passive smoking has recently been ranked right behind active smoking and alcohol as the third leading cause of preventable death in this country.
While people usually think of cancer as the major danger of cigarette smoking, passive smoking is estimated to lead to 10 times more deaths each year from heart disease than from lung cancer.
Studies show that smoke coming from the end of a burning cigarette (sidestream smoke) contains larger amounts of the substances that cause heart disease and lung cancer than is inhaled by the smoker directly through the cigarette.
Noxious compounds in sidestream smoke are carried on smaller particles than those found in direct smoke and are deposited deeper in the lungs. Small particles are cleared more slowly by the natural defenses of the lungs, and substances carried on these particles slowly dissolve in to the lung tissues, then enter the bloodstream, where they add to narrowing of the coronary arteries.
Passive smoking also may decrease the exercise capacity of healthy adults. But its worst effects appear to be on children and those who already have heart or lung disease. The children of smoking parents (especially if the mother smokes) have a higher prevalence of wheezing, coughing, bronchitis, pneumonia and middle ear disease.
Dr. Margolis is professor of medicine and biological chemistry at the Johns Hopkins School of Medicine and associate dean for faculty affairs at the school.