There is strong LD between all three SNPs in the population of European ancestry in HapMap (Fig. 1A), and, in our study population, r2 values in whites were more than 0.88 between any combination of the three SNPs. In a stepwise logistic regression analysis in whites that did not include cigarettes smoked per day, only rs931794 remained in the model as significantly associated with lung cancer risk. However, once smoking quantity was included, this SNP was not significantly associated with lung cancer risk in whites. In the Yoruban population in HapMap, there is little LD in this region (Fig. 1B). In our population of African Americans, r2 values were 0.24 or less between SNPs. When all three SNPs were included in a logistic regression model in a stepwise fashion in African Americans, only rs1051730 was predictive of risk.
