1. Department of Clinical Epidemiology (O.M.D., S.C.C., J.P.V.), Leiden University Medical Centre, Leiden 2300RC, The Netherlands
2. Department of Clinical Endocrinology (O.M.D., A.M.P.) and Metabolism, Leiden University Medical Centre, Leiden 2300RC, The Netherlands
3. Department of Clinical Epidemiology (E.H.-P., V.E.., H.T.S.), Aarhus DK-8000, Denmark
4. Department of Medicine (J.O.L.J.), Aarhus University Hospital, Aarhus DK-8000, Denmark