The finding of a weak or absent association between AFD and later alcohol problems, after observed associations are attenuated with rigorous control for confounders, provides some support for a marker hypothesis.8 Put simply, those who possess an underlying vulnerability to alcohol problems may also be likely to start drinking early. Further support for the marker hypothesis may be inferred from the lack of strong evidence for the long-term effectiveness of interventions which aim to reduce alcohol related harm by preventing underage drinking.12 30 31 These reviews suggest that delaying AFD does not impact on long-term problems. The most recent findings by Guttmannova et al21 rejecting a marker hypothesis should, however, be borne in mind.
