1. From the Department of Human Genetics, Graduate School of Public Health, University of Pittsburgh, Pittsburgh, PA (V.N., X.W., D.P., Z.H.R., M.M.B., F.Y.D., M.I.K.); and Department of Epidemiology, Colorado School of Public Health, University of Colorado Anschutz Medical Campus, Aurora, CO (J.E.H., R.F.H.).