Physical activity assessment methods in the Jackson Heart Study.
OBJECTIVES: Physical activity measures used in exam 1 of the Jackson Heart Study (JHS), including the diet and physical activity substudy (DPASS), are described. DESIGN: The JHS physical activity (PAC) survey instrument was administered by interview. Accelerometer data, pedometer step counts, and additional questionnaire data were collected from volunteer subsamples of the cohort, including the DPASS. OUTCOME MEASURES: The PAC assessed four different domains of physical activity (active living, work, home and garden, and sport and exercise indexes). The 24-hour accelerometer and pedometer monitoring provided objective measures for validation of cohort survey responses. The DPASS past week activity (PWA) questionnaire assessed time spent in moderate and vigorous activity during the previous seven days. Pedometer step counts for three days before three DPASS visits provided additional data for the DPASS. RESULTS: 5296 respondents completed the PAC, 423 completed 24-hour accelerometer monitoring, and 499 completed the DPASS measures; 85 completed both 24-hour monitoring and DPASS measures. Initial analyses of leisure and sports activity items showed similar distributions for men and women and for the cohort and DPASS participants, in a bimodal distribution, with similar proportions reporting infrequent and frequent activity. The physical activity measures from the JHS can provide unique information about the association between physical activity, other risk factors, and cardiovascular disease in African Americans.