Smoking Habits in Lung-Cancer Proband Families and Comparable Control Families

Summary

The pattern of the familial smoking behavior was analyzed and compared between parents, siblings, and children of 270 lung cancer probands and the counterparts of 270 controls selected within the same community. The information regarding lifetime smoking experience was ascertained for 90 percent of all living and dead relatives being studied. The distribution of parents, siblings, and children by year of birth as well as the size of sibship and of family were comparable between the two family populations. With respect to cigarette smoking among the index subjects the following findings may be of interest: 1) Smoking at young ages is related to lung cancer. 2) The amount of daily smoking (one pack or more) is related to lung cancer. 3) The duration of smoking (40 years or more) is related to lung cancer. Three different aspects of cigarette smoking among the relatives were analyzed with the following results: 1) The relatives of the lung cancer probands are more likely to be smokers than those of the controls. 2) About 40 percent of the case relatives are smokers regardless of the smoking status of the probands; in contrast, 40 percent of those control relatives whose index subjects are smokers, as compared with 30 percent of those control relatives whose index subjects are nonsmokers, are smokers. 3) In both proband and control families, children are more likely to be smokers if their parents are smokers. The results of our analyses do not seem to support R. A. Fisher's “common genotype” hypothesis regarding lung cancer and smoking behavior.