African-American vs. 5.5% of European-American MOAFTS participants). Our conclusions regarding the relative contributions of genetic and environmental factors to the timing of first drink therefore may not generalize to the phenotype of any lifetime use. Fourth, although minimized by the short lag time from first use and/or symptom onset to time of interview (and the use of the first report when more than one report was available), the potential bias introduced by retrospective reporting should be considered, particularly if it varies by ethnicity.
