Actigraph Accelerometer Validation Study

The NCI is collaborating with other NIH Institutes on a proposed extramurally funded longitudinal study of Hispanic subpopulations in the United States referred to as the Hispanic Community Health Study (HCHS). Hispanic populations are understudied with respect to many diseases and risk factors. To better understand the relationship between physical activity and chronic disease, and to make specific activity prescriptions, better methods are needed to improve the validity and reliability of physical activity assessment instruments to assess the frequency, duration, and intensity of physical activity. In preparation for use in the HCHS, NCI plans to evaluate a new type of accelerometer, a small device worn on a belt at the waist that measures and records movement, capturing movement intensity and duration and associating it with clock-time. This new accelerometer will be used in the HCHS to allow examination of levels as well as patterns of activity. Physical activity was measured with accelerometers in the nationally representative 2003-2006 National Health and Nutrition Examination Survey (NHANES). Between the time of the NHANES and the HCHS, there has been a change in the technology of the accelerometer used in NHANES. To allow comparison of the physical activity data that will be collected in the HCHS to the data collected with the previous technology used in NHANES, a cross-validation study is needed. The proposed study, the ActiGraph Accelerometer Validation Study, will compare the ActiGraph model 7164 used in NHANES with the new model GT1M to be used in the HCHS by simultaneously collecting physical activity data using both ActiGraphs under different circumstances of walking or jogging. The study will recruit 120 men and women ages 18-74, corresponding to the age range of the HCHS. Normal weight, overweight and obese participants will be included in each age/gender cell. Because the devices measure movement, it is not essential that the study participants be from any particular ethnic group. To derive comparable data for the 2 devices, the 2 accelerometer models will be worn on a belt, with one positioned on each hip. Study participants will be asked to walk/jog around a track for a known distance at several self-selected paces. Minute-by-minute and summary data from the two devices will be evaluated for comparability.