In a subset of cases with a family history of lung cancer, all SNPs were associated with increased risk in whites when cigarettes smoked per day was not included in the model, and rs1051730 remained significant in whites with a family history of lung cancer after adjusting for sex and cigarettes smoked per day (OR 1.41; 95% CI 1.03–1.91; Table 4). This SNP was also associated with lung cancer risk among African Americans with a family history of lung cancer (OR 1.83; 95% CI 1.10–3.06). In general, among African Americans, family history did not greatly change estimates of risk for any of the three SNPs. Risk varied by age at lung cancer diagnosis in whites, with young onset disease associated more strongly with these SNPs than in later onset lung cancer, but again after adjustment for cigarettes per day no significant increases in lung cancer risk were evident. In African Americans, risk patterns were similar across age groups, but statistically significant risks were only seen in those 50 years of age or older. There were no significant differences by sex (data not shown).
