Effects of Environmental Tobacco Smoke on Urinary Cotinine Excretion in Nonsmokers: Evidence for Passive Smoking

Despite recognition of the deleterious effects of passive smoking, quantitative information on the intake of environmental tobacco smoke is still lacking. Cotinine is the major metabolite of nicotine found in the urine. We have examined the relationship between urinary cotinine excretion in 472 nonsmokers and the smokiness of their environment. The urinary cotinine levels of nonsmokers who lived with smokers were higher than those of non-smokers who did not, increasing with the combined daily cigarette consumption of smokers in the family. The urinary cotinine values of nonsmokers who worked with smokers were also higher than those of nonsmokers who did not, increasing with the number of smokers in the workroom. The presence of smokers in both the home and the workplace also increased the cotinine levels. Urban nonsmokers had more cotinine in their urine than rural nonsmokers. We conclude that the deleterious effects of passive smoking may occur in proportion to the exposure of nonsmokers to smokers in the home, the workplace, and the community. (N Engl J Med 1984; 311:828–32.) SINCE the recognition of the deleterious effects of cigarette smoking on health, concern has shifted to the health consequences in nonsmokers of exposure to environmental tobacco smoke. 1 , 2 Recent studies have shown that passive smoking by nonsmokers may acutely aggravate angina pectoris, 3 induce small-air-way dysfunction, 4 , 5 and increase the risk of lung cancer, although there is still controversy regarding a relation to lung cancer. 9 However, quantitative studies on the amount of tobacco smoke that nonsmokers inhale from the environment are few and inconclusive. Estimation of suspended particulates, 10 , 11 carbon monoxide levels, 10 , 12 and nicotine levels 13 , 14 in the atmosphere of closed spaces has been undertaken . . .