Internet-Based and Self-Reports in Assessing Diet and Physical Activity Within AARP

PRIMARY OBJECTIVES: I. Evaluate the measurement error structure of self-reported dietary assessment instruments, including, a food frequency questionnaire (National Cancer Institute \[NCI\]'s Diet History Questionnaire-II \[DHQ-II\]), and 24-hour recalls using the new automated self-administered 24-hour dietary recall (ASA24) instrument with respect to absolute energy intake, absolute protein intake, and protein density-and potentially other nutritional factors such as potassium intake. II. Investigate the measurement error structure associated with self-reported active and sedentary behaviors, including multiple administrations of a new 24-hour recall (activity completed over time in 24-hours \[ACT24\]) and selected questionnaires using energy expenditure from doubly labeled water (DLW) and physical activities measures of physical activity monitors as reference instruments. III. Evaluate alternative analytic approaches for combining different types of self-report data on diet and physical activity-related behaviors as well as self-report plus objective data (derived from activity monitors, heart rate monitors e.g.). IV. Within the context of an AARP-based cohort, explore the adjustment of observed RRs for several key cancer hypotheses related to diet and physical activity based on the measurement error data provided by the new study. V. Evaluate the potential for 'energy adjustment' that incorporates physical activity and body size. OUTLINE: Patients complete the ASA24 about foods, cooking methods, and other aspects of diet every 2 months for up to 6 times, and complete ACT24 about activities and time reporting every 2 months for up to 6 times. Patients also complete DHQ-II questionnaires at the beginning and end of the study about the frequency and portion sizes of foods consumed over the past 12 months, provide a 7-day food checklist twice with the DHQ-II, and provide a 4-day food record twice, once every 6 months. Physical activity monitors are worn to measure movement at different intensity levels and sitting or standing periods, twice during the study with 6 months between each time they are worn.