[1] Erasmus MC, Dept Publ Hlth, Rotterdam, Netherlands
[2] Fred Hutchinson Canc Res Ctr, Publ Hlth Sci Div, Seattle, WA USA
[3] Mem Sloan Kettering Canc Ctr, Dept Epidemiol & Biostat, New York, NY USA
[4] NYU, Sch Med, Dept Populat Hlth, Div Epidemiol, New York, NY USA
[5] Kaiser Permanente Washington Hlth Res Inst, Biostat Unit, Seattle, WA USA
[6] Kaiser Permanente Northern Calif, Div Res, Oakland, CA USA
[7] Kaiser Permanente San Francisco, Dept Gastroenterol, San Francisco, CA USA
[8] Erasmus MC, Dept Publ Hlth, POB 2040, NL-3000 CA Rotterdam, Netherlands