1. Prevention Research Center (A.Z.F., M.R.), Pacific Institute for Research and Evaluation, Berkeley, California 94704
2. Clinical Science Research Institute (S.S.), University of Warwick, Coventry CV4 7AL, United Kingdom
3. Department of Social and Preventive Medicine (S.S., J.D., M.T.), School of Medicine and Biomedical Sciences, University at Buffalo, Buffalo, New York 14214