[1] Mem Hosp Rhode Isl, Ctr Primary Care & Prevent, Pawtucket, RI USA
[2] Tech Univ Munich, Klinikum Rechts Isar, Munich, Germany
[3] Univ Calif San Diego, San Diego, CA 92103 USA
[4] Univ North Carolina Chapel Hill, Dept Epidemiol, Chapel Hill, NC USA
[5] Univ Bern, Bern, Switzerland