[1] Cornell Univ, Weill Med Coll, New York, NY USA
[2] Sahlgrenska Ostra Univ Hosp, Gothenburg, Sweden
[3] Ullevaal Univ Hosp, Oslo, Norway
[4] Univ Michigan, Ann Arbor, MI 48109 USA
[5] City Hosp, Birmingham, W Midlands, England
[6] Karolinska Univ Hosp, Stockholm, Sweden
[7] Univ Helsinki, Cent Hosp, FIN-00014 Helsinki, Finland
[8] Glostrup Univ Hosp, Copenhagen, Denmark
[9] Merck Res Labs Scandinavia, Stockholm, Sweden
[10] Viborg Hosp, Viborg, Denmark
[11] Umea Univ, S-90187 Umea, Sweden
[12] Haukeland Univ Hosp, N-5021 Bergen, Norway
[13] Univ Alabama, Birmingham, AL USA
[14] Nordic Sch Publ Hlth, Gothenburg, Sweden
[15] Merck & Co Inc, Whitehouse Stn, NJ USA