1. From the Departments of Biostatistics (K.P.J., R.C.N., D.B., F.D.) and Environmental Health (S.W.D.), Harvard T.H. Chan School of Public Health, Boston; the Department of Biostatistics, Mailman School of Public Health, Columbia University, New York (X.W.); and the Department of Urban and Regional Planning, University of Colorado Denver, Denver (P.D.).