College attendance and its effect on drinking behaviors in a longitudinal study of adolescents

While college attendance has been shown to be associated with increased drinking behaviors, there are no studies to our knowledge that have examined whether college attendance moderates genetic influences for drinking. We first tested for changes in alcohol consumption in adolescents who did and did not subsequently attend college, and then tested for variation of the genetic and environmental determinants of drinking in these 2 groups.

Participants eligible for this study were selected from 2 samples from the National Longitudinal Study of Adolescent Health (Add Health), a national probability sample (n=7,083) and a sample of sibling pairs (n=855 pairs). Participants were assessed for measures of drinking behaviors as adolescents (wave I) and reinterviewed at 1 (wave II) and 6 years (wave III) following the initial survey. Changes in binge drinking and average quantity of alcohol consumed in the past year were estimated among 4 groups (2-year college students, 4-year college students, college withdrawers, noncollege participants) in sequential cohorts which spanned the ages of 13 to 24 across the 3 Add Health waves. Gene by environment interactions were then tested at wave III using biometrical models in the genetically informative pairs.

Participants who did not attend college reported more binge drinking and consumed greater quantities of alcohol as adolescents than participants who subsequently attended college. However, the college students not only surpassed their noncollege peers in alcohol use as young adults, but also exhibited a greater genetic influence on quantity of alcohol consumed per drinking episode.

Exposure to a college environment acts as an environmental moderator, supporting the hypothesis that the magnitude of genetic influence on certain aspects of alcohol consumption is greater in environments where drinking behaviors are more likely to be promoted.