The participants reported drinking an average of 4.9 (SD = 2.4) standard drinks per drinking episode at a frequency of twice per week (6 = twice a week, M = 6.18; SD = 1.38) during the past year. Allele frequencies for the OPRM1 and tSNPS for OPRK1 and OPRD1 are presented in Table 1. Assessment for violation of Hardy-Weinberg Equilibrium (HWE) resulted in no significant chi-square values (ps>0.05, Table 1), with the exception of OPRD1^4 which reached marginal significance (p=0.051). HWE was then re-estimated among Whites only, which suggested no violation for OPRD1^4 (χ2 = 1.91, p = 0.16).
