Recontacting Participants in the Observing Protein and Energy Nutrition (OPEN) Study: Re-OPEN

This study will evaluate the structure of error in self-reporting instruments on diet, in following up the Observing Protein and Energy Nutrition Study (OPEN) conducted in 1999 and 2000. The OPEN study, the largest of its kind, resulted in a wealth of nutritional biomarker data-measurable indicators of changes in organisms at the level of molecules or cells. A biomarker could help in understanding how environment and disease are related and about disease risks. Furthermore, its findings showed that the relative estimates of disease risk may be weakened by a food frequency questionnaire and a 24-hour questionnaire. Scientists have long recognized that self-reported information from questionnaires and interviews contains errors, but there has been uncertainty about the structure of such errors. For the proposed study, a food record and a food checklist-adjusted food frequency questionnaire will be compared with the previously used questionnaires, to determine whether the newer study instruments present less chance of measurement error. The results may provide better tools for a study on nutritional epidemiology, that is, the incidence and other aspects of disease and nutrition. OPEN study participants will be invited for follow-up. Patients who completed the 1999-2000 study who are not currently pregnant or a liquid weight loss diet may be eligible for this study. The original study recruited men and women 40 to 69 years of age. A letter with summary results from the original OPEN study will be sent to each of the 482 participants. Both the Food Record and the food checklist, called the Daily Food List, are instruments to be given. The Food Record asks the participant to record all foods and beverages consumed. The Daily Food List asks respondents to write in to the number of times a limited number of food categories are consumed. In addition, respondents will be asked to complete the National Cancer Institute Diet History Questionnaire (DHQ), identical to the one t