Social Activities, Genetic Influences, and Drinking in First-Year College Students

Background and Purpose: The inaugural college year is a particularly vulnerable time for harmful drinking. The current study examined the associations between first-year students’ involvement in college social activities and alcohol use. We considered the interactive effects of social activity participation and genetic influences related to alcohol metabolism on student drinking and alcohol dependence problems. The ADH1B and ADH4 genes encode enzymes involved in the process of alcohol metabolism. A slower metabolism of ethanol (to acetaldehyde) is associated with drinking more alcohol and greater risk for alcohol dependence.

Methods: Data were from a study of undergraduate students enrolled at a 4-year public university with an ethnically-diverse student body. Participants were first-year students (N=2714), median age 18.46 years, and included drinkers who reported consuming at least one lifetime alcoholic drink (n=1699). Social activities participation (i.e., organized sports; fraternity/sorority; school activities; community activities; and church-related) was rated as never, rarely, sometimes, and often. Alcohol use was measured by current drinking characteristics (quantity x frequency) and alcohol dependence problems (count of 0-7 DSM-IV symptoms since attending VCU). Students provided saliva samples for DNA. Genetic markers included ADH1B-rs1229984, ADH1B-rs2066702, and ADH4-rs1126671; these are missense mutations associated with amino acid changes that alter the rate of metabolism. Chi-square and regression-based analyses were used to test relationships between social activities, genetic markers, and alcohol use and dependence problems. Analyses involving genetic data included African American and European American drinkers only (n=178 and n=575, respectively) and tested gene-by-environment interaction effects.

Results: Student drinkers, compared to non-drinkers, had more frequent participation in sorority/fraternity activities, and participated less frequently in school, community, and church-related activities. Organized sports participation was associated with more drinking. Student fraternity/sorority involvement was associated with both increased drinking and alcohol dependence problems. The relationship between more frequent fraternity/sorority participation and alcohol dependence was robust; remaining significant (p<.045) after accounting for participant drinking characteristics, alcohol expectancies, access to alcohol, and peer drinking. Significant gene-by-environment interactions were identified (p’s<.024). At ADH1B-rs2066702 (G/G or G/A versus A/A) and ADH4-rs1126671 (T/T or C/T versus C/C), risk variants were more strongly associated with alcohol use in the context of more frequent fraternity/sorority participation and with alcohol dependence problems with more frequent organized sports participation. Gene-by-environment interaction effects for ADH1B-rs1229984 (C/C; C/T; or T/T) were non-significant.

Conclusions and Implications: Our analysis of gene-by-environment relationships provides support for the importance of targeting risky college social activities for drinking. Prevention efforts targeted at fraternity/sorority activities and organized sports involvement may help reduce risky drinking in first-year college students, especially in those students who are carriers of alcohol metabolism genetic risk variants. The relationship of fraternity/sorority participation with alcohol dependence problems is not unexpected. Our analyses showed that this relationship remained robust even after controlling for other individual and social risk factors.