Differentiating the Contribution of Context-Specific Social Influences on Underage Youth's Alcohol Consumption.

Background and objectives: We examined associations between sources of social influence (i.e. close friends, other underage people present) within specific settings with the number of drinks underage youth consumed.

Methods: Data were collected through a cross-sectional survey with 422 underage youth in California (14 to 19 years old) who reported past-6-month alcohol use. Participants were asked to think about the last time they drank alcohol in the past 6 months at: restaurants, bars/nightclubs, own home, another's home, outdoors, and fraternities/sororities. Outcomes were the number of whole drinks participants drank the last time in each setting. Independent measures were social characteristics of these drinking events including number of people <21 years old present, number of close friends present, number of <21 years old who consumed alcohol, and number of close friends who consumed alcohol. We also assessed socio-demographics and accounted for the overall exposure to each setting in the past 6 months.

Results: Using negative binomial regression models, the number of close friends was positively associated with number of drinks consumed at restaurants, another's home, and outdoors. The number of close friends drinking was positively associated with the number of drinks at restaurants, own home, another's home, and outdoors. Number of people <21 years old was positively associated with number of drinks at own home, and number of people <21 years old who consumed alcohol was positivity associated with number of drinks consumed at restaurants, own home, another's home, and outdoors.

Conclusions: Results suggest that social influence from close friends and from other underage youth are context-specific.