Most studies used a rigorous approach to AFD measurement by collecting data on this variable at multiple points during adolescence, and taking the first report of alcohol use in their analysis.18–21 Confounding is most extensively controlled for by Warner and White19 with reasonable levels of control also employed by Guttmannova et al20 21 and to a lesser extent by Rossow and Kuntsche.22 The possibility of overadjustment should be borne in mind, where for example peer variables may lie on the causal pathway to adult outcomes as well as being implicated in earlier AFD.
