FAMILIAL FACTORS IN HUMAN LUNG CANCER AND SMOKING

Abstract

Analyses of mortality data on relatives of 270 lung cancer probands and 270 controls matched for race, sex, age and residence indicate a significant excess in lung cancer among proband relatives. This relation was found among relatives of both smokers and nonsmokers, but not among spouses. Familial effect was more marked among nonsmokers than among smokers, whereas smoking effect was more evident among control relatives than among proband relatives. Effect of smoking may be greater than a familial factor in men; there was no indication that this was the case in women. No difference in lung cancer mortality was found between non- smoking male and female relatives of probands. There seems to be a synergistic interaction between familial and smoking factors. Proband relatives were more likely to be smokers than control relatives. Data also showed that smokers tend to aggregate in families. Proband relatives appeared to have common susceptibility to all respiratory diseases. Data suggest that genetic factors may play a role in lung cancer.