estimated standardized mean difference between the ALDH2 groups grew from d = −.07 at age 15, to .22 at age 18 and .40 at age 22. Likewise, the predicted probabilities of alcohol abuse or dependence diagnosis showed the protective effect of the ALDH2*2 allele increased with age, from OR = 2.29 at age 15, to 1.10 at age 18 and .42 at age 22. Although the OR might suggest that ALDH2*2 is associated with increased risk at age 15, it is important to recognize that rates of diagnosis are very low at this age (approximately 2% for both genotypes), in which case the estimated OR is statistically unstable.
