1. The Endocrine Research Unit, Division of Endocrinology and Metabolism (H.M.H., S.K., B.L.R.), Rochester, Minnesota 55905
2. Department of Laboratory Medicine and Pathology (M.F.B.), Rochester, Minnesota 55905
3. the Section of Biostatistics, Department of Health Sciences Research (W.M.O.), Mayo Clinic and Mayo Foundation, Rochester, Minnesota 55905