hypothesized to confer. The diplotype hypothesized to confer high risk included the absence of the protective allele for both rs698 and rs1229984: G-G, G-G. Diplotypes hypothesized to confer intermediate risk included the absence of the protective allele for rs1229984 only: A-G, A-G (rs698=AA, rs1229984=GG) and A-G, G-G (rs698=AG, rs1229984=GG). Of those without the protective allele for rs698, 95.7% also lacked the protective allele for rs1229984; thus, the diplotype categories can be viewed as dividing up the rs1229984 group without the protective allele into those with the protective allele for rs698 (intermediate risk group) and those without the protective allele for rs698 (high risk group). (Note that there is no category for absence of protective allele for rs698 with presence of protective allele for rs1229984 due to the haplotype structure. Accordingly, we did not formally test interaction between ADH1B-rs1229984 and ADH1C-rs698.) Diplotypes hypothesized to confer low risk had protective alleles for both rs698 and rs1229984. To investigate the association of the diplotype variable with the alcohol phenotypes, adjusted logistic or Poisson regression analyses were carried out, and ORs/RRs were calculated for all comparisons, to determine if both ADH1B and ADH1C played a role in increasing risk.
