1. Department of Epidemiology (S.T.H., L.C., S.S., P.M.), University of Alabama at Birmingham.
2. Department of Medicine (A.L.C.), University of Alabama at Birmingham.
3. Department of Medicine, Columbia University, New York, NY (N.M., M.A.).
4. Department of Biostatistics (B.C.J.), University of Alabama at Birmingham.
5. Department of Epidemiology, Johns Hopkins University, Baltimore, MD (K.F.).
6. American Medical Association, Chicago, IL (G.W.).