1. Department of Epidemiology (J.B.L., T.S., M.A.B.), Chapel Hill, North Carolina 27599
2. Sheps Center for Health Services Research (D.L., M.A.B.), Chapel Hill, North Carolina 27599
3. Department of Pharmaceutical Sciences (C.R.M.), University of Basel, 4003 Basel, Switzerland
4. Department of Medicine (J.L.S.), University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599
5. Department of Epidemiology (S.S.J.), Boston University, Boston, Massachusetts 02118