Familial cancer history and lung cancer risk in United States nonsmoking men and women.

The authors conducted a population-based case-control study of lung cancer in nonsmoking men and women in New York State from 1982 to 1984. Nonsmokers included both never smokers (45%) and former smokers who had quit at least 10 years before diagnosis/interview (55%). In-person interviews were completed for 437 lung cancer cases and 437 matched population controls. Cases and controls were asked to report on their family history of cancer, as well as smoking status of family members. Cases were significantly more likely than controls to report having a paternal history of any cancer [odds ratio (OR), 1.67] and aerodigestive tract cancers (OR, 2.78); a maternal history of breast cancer (OR, 2.00); a history of any cancer in brothers (OR, 1.58) and sisters (OR, 1.66); and a nearly significant excess of lung cancer (OR, 4.14; P = 0.07), aerodigestive tract cancer (OR, 3.50; P = 0.06), and breast cancer (OR, 2.07; P = 0.053) in sisters. The excess risk in relatives of cases as compared to relatives of controls also was evident in a cohort analysis of the relatives. These results support the hypothesis of a genetic susceptibility to various cancers in families with lung cancer in nonsmokers.