reported that none of their close friends drank alcohol at least once a month. Each variable was associated with age (polyserial correlations r = 0.40–0.50). Friends' alcohol use was associated with adolescent own quantity of alcohol use (polychoric correlation r = 0.66) and alcohol problem use (polychoric correlation r = 0.72). Ordered logistic regression was used to examine the associations between friends' alcohol use and adolescent own alcohol use. Friends' alcohol use predicted both quantity of alcohol use (b = 1.087, t = 13.95 P < 0.001) and alcohol problem use (b = 1.111, t = 14.10 P < 0.001) in analyses controlling for age, gender and zygosity.
