1. From the Departments of Food Technology (KK, HT, and AK), Public Health (JK and KS), and Medical Genetics (MP), University of Helsinki, Helsinki, Finland; the Departments of Molecular Medicine (KK, AK, and MP) and Mental Health and Alcohol Studies (JK), National Public Health Institute, Helsinki, Finland; and the Twin Research and Genetic Epidemiology Unit, St Thomas' Hospital, Kings College Lond