1. Participation rates in telephone administered 24-h-recalls Experience from the Norwegian EPIC cohort

2. The Norwegian Women and Cancer study (NOWAC) Lund E, et al.: Int J Epidemiol. 2008 Feb;37(1):36-41

3. The Norwegian EPIC cohort Sub cohort from NOWAC Participants answered a second questionnaire in 1998 Women aged 41-56 EPIC-calibration study, single 24-HDR Comparison study, face-to-face/telephone Validation study: 4 x 24-HDR, questionnaire (Dr. A. Hjartåker)

4. Participation rates 1. Questionnaire: 57% 2. Questionnaire: 82% Single 24-HDR: 61 % (3000 invited, 2 reminders) Comparison study: Face-to-face: 69,4% - 63,8% (160 invited, 2 reminders) Telephone: 60,4% - 57,2% (180 invited, one reminder) ( M Brustad et al.: EJCN (2003) 57, 107–113) Validation study: 4 x 24-HDR: 57,2 % - 56,6% (500 invited, 2 reminders) Questionnaire: 84% (238 of 283) (A Hjartåker et al.: Public Health Nutrition (2007): 10(10), 1094–1103)

5. Thank you!