Lung cancer and exposure to tobacco smoke in the household.

BACKGROUND: The relation between passive smoking and lung cancer is of great public health importance. Some previous studies have suggested that exposure to environmental tobacco smoke in the household can cause lung cancer, but others have found no effect. Smoking by the spouse has been the most commonly used measure of this exposure. METHODS: In order to determine whether lung cancer is associated with exposure to tobacco smoke within the household, we conducted a population-based case--control study of 191 patients with histologically confirmed primary lung cancer who had never smoked and an equal number of persons without lung cancer who had never smoked. Lifetime residential histories including information on exposure to environmental tobacco smoke were compiled and analyzed. Exposure was measured in terms of "smoker-years," determined by multiplying the number of years in each residence by the number of smokers in the household. RESULTS: Household exposure to 25 or more smoker-years during childhood and adolescence doubled the risk of lung cancer (odds ratio, 2.07; 95 percent confidence interval, 1.16 to 3.68). Approximately 15 percent of the control subjects who had never smoked reported this level of exposure. Household exposure of less than 25 smoker-years during childhood and adolescence did not increase the risk of lung cancer. Exposure to a spouse's smoking, which constituted less than one third of total household exposure on average, was not associated with an increase in risk. CONCLUSIONS: The possibility of recall bias and other methodologic problems may influence the results of case-control studies of environmental tobacco smoke. Nonetheless, our findings regarding exposure during early life suggest that approximately 17 percent of lung cancers among nonsmokers can be attributed to high levels of exposure to cigarette smoke during childhood and adolescence.

Tetanus antitoxin titers in women of childbearing age from nine diverse populations.

The proportion of women with tetanus antitoxin titers adequate to provide protection for themselves and for their newborn infants varied from 96% in New Haven, Connecticut to 19% in Santiago, Chile. Women of childbearing age in five of the nine areas (São Paulo, Recife, and Pôrto Alegre, Brazil; Ecuador; and Gazankulu, South Africa) had an average of 40% immunity to tetanus and did not differ significantly from one another. By comparison with Chile, where vaccination during pregnancy is not current policy, we estimate that 21%-34% of the women in these five areas had received toxoid recently. In general about half the women with inadequate titer had undetectable levels of antibody and may require more than one dose of vaccine to attain immunity.