Factors Related to Maximum Number of Drinks in a 24-hour Period In Chinese- and Korean- American College Students J. Chen, S.E. Luczak, B. Trischler, J. Lam, J. Lee, S.H. Shea, T. Liang, & T.L. Wall University of California, San Diego and Veterans Medical Research Foundation Introduction Ø The maximum number of drinks ever consumed in a 24-hour period (Max Drinks) has been shown to be a heritable trait in twin studies. Ø Max Drinks is a single-item measure of lifetime heavy drinking. It is thought to reflect an individual’s capacity to metabolize alcohol, and is one of several variables that differentiate individuals who develop alcohol dependence from those who do not. Ø The primary pathway of alcohol metabolism involves two different enzymes, see Figure 1. The enzyme alcohol dehydrogenase (ADH) catalyzes the first step of alcohol metabolism, and the enzyme aldehyde dehydrogenase (ALDH) catalyzes the second step. Method 0 Participants (52% female) Korean-American college students, 21 - 26 years of age. Ø A blood sample from each participant was Ø The SSAGA was used to determine participants lifetime Max Drinks as well as the age and context of the drinking occasion. Data Analysis Ø ANOVAs were conducted to determine if Max Drinks was related to ethnicity and to the ALDH2 and ADH1B genes. Results 8.8 10 9.3 12.2 15 was significantly associated with Max Drinks in both Chinese and Koreans, however, ADH1B*2 was not. was significantly associated with Max Drinks in both Chinese (F = 14.2, df = 2, p < .001) and Koreans (F = 4.5, df = 2, p = .011). Ø As hypothesized, Chinese and Korean individuals without ALDH2*2 alleles had the highest average Max Drinks (8.8 and 12.2) followed by those with one (6.2 and 9.3) and then two (3.3 and 8.0) ALDH2*2 alleles, although in Koreans only the difference between those with no and two alleles was significant. 0 Chinese Koreans sknirD naeM _____________________________________________________________________________________________________________________________________ 5 0 ADH1B*1/2*1 ADH1B*1/2*2 5 5.6 10 10.4 11 11.1 Korean 7.7 Ø ADH1B*2 15 Males 14.6 Females was not significantly associated with Max Drinks in either ethnic sample: Chinese, F=1.31 (2, 403), p = .271 Korean F=10.22 (2, 376), p = .805. Ø 9.1 participants had lower average Max Drinks (7.4 vs. 11.2, t=7.6, p<.001) than Korean participants. % of participants reported their Max Drinks occurred on their 21st birthday, but neither ALDH2*2 or ADH1B*2 alleles was associated with Max Drinks occurring on one's 21st birthday. Ø Due to ethnic difference and the issue of Ø Neither ALDH2*2 or ADH1B*2 was associated Ø Chinese population stratification, analyses were conducted separately for Chinese and Korean participants. individual’s alcohol intake (or capacity to drink), thereby contributing to their overall lower risk for developing alcohol dependence. Ø Limitations to the study include the use of self-report measures collected at one time point, a volunteer sample, and a restricted age range. This research was funded by NIH Grants: R01 AA11257, K02 AA00269, and K08 AA14265. 7.3 7.6 Chinese Ø Previous studies have shown an association of Ø These findings suggest ALDH2*2 lowers an ADH1B*2/*2 15 9 which Max Drinks was consumed. Acknowledgements 5.6 10 Ø Neither genotype was associated with age at ADH1B sknirD naeM Max Drinks college students were significantly more likely to have an ALDH2*2 allele and had a lower average maximum number of drinks ever consumed in a 24-hour than Korean-American college students. Because of these ethnic differences, analyses were conducted separately for Chinese and Koreans. Ø ALDH2*2 Ø ALDH2 to Korean American participants, Chinese American participants were more likely to have an ALDH2*2 allele (47% vs. 32%, x2 = 18.5, df = 2, p < .001). ADH1B*2 allele prevalence did not differ by ethnicity. Primary Pathway of Alcohol Metabolism ADH1B*2 alleles would have lower average Max Drinks. We explored whether Max Drinks occurred on one’s 21st birthday. 8 Ø Compared Figure 1. Ø We hypothesized individuals with ALDH2*2 and 5 genotyped at the ALDH2 and ADH1B loci. ØBoth ADH1B*2 and ALDH2*2 alleles have been ALDH2*2 with Max Drinks in Asian populations, and ADH1B*2 has also been associated with Max Drinks in Caucasians. Ø Chinese-American 3.3 6.2 Data Collection Ø ALDH2 is one of the forms of ALDH. ALCOHOL ACETALDEHYDE ACETATE Alcohol Dehydrogenase Aldehyde Dehydrogenase (ADH) (ALDH) _________________________________________________________________ Summary of Findings Ø 406 (50% female) Chinese-American and 379 Ø ADH1B is one of the forms of ADH. associated with reduced risk for alcohol dependence. Discussion ALDH2 with age at which Max Drinks was consumed.