Objective: A recent report found the heritability estimate for alcohol-induced blackouts was 53%. The present study was designed to determine whether possession of two specific genetic variations, an aldehyde dehydrogenase ALDH2*2 allele and an alcohol dehydrogenase ADHIB*2 allele, were associated with lower rates of lifetime blackouts.
Method: Asian American college students (N=403) of Chinese and Korean descent were genotyped at the ALDH2 and ADHIB loci and assessed for lifetime alcohol-induced blackouts and the maximum number of drinks ever consumed in a 24-hour period.
Results: Participants who had an ALDH2*2 allele had approximately one third the risk of having a lifetime blackout of participants without this allele. Rates of experiencing a lifetime blackout did not significantly differ by ADHIB*2 status. Possessing an ALDH2*2 allele was associated with decreased risk of lifetime blackouts even after controlling for maximum number of drinks ever consumed in a 24-hour period and ethnicity.
Conclusions: These findings suggest the protective effects of possessing an ALDH2*2 allele include a lowered risk of experiencing alcohol-induced blackouts.