FUNDING SOURCE: CDC PRC Special Interest Project, U48/CCU409664 SIP 13-00  (2000-2002)


CO-INVESTIGATORS: Barbara Ainsworth, PhD, MPH and Cheryl Addy, PhD

This special interest project had four specific aims; (1) to develop and cognitively test candidate short physical activity questionnaires (1 to 3 items) that can classify individuals into one of three physical activity surveillance categories (i.e., inactive, insufficiently active, meets recommendations), (2) conduct a reliability and validity study to identify the instrument that most accurately classifies individuals into the surveillance categories, (3) conduct a national survey of US adults, with over-sampling of African-Americans, and compare prevalence estimates between the new instrument and existing activity surveillance instruments, and (4) disseminate results from the work outlined in aims 1 through 3.

Aim 1: As a result of development and cognitive testing completed in July 2001, two candidate instruments (3 items each) were refined for validation testing.

Aim 2: The instruments were validated using activity monitors (accelerometers) and fourteen 24-hour physical activity recalls as criterion measures in a 28-day study period. After ten months of recruitment; we enrolled 108 adults in the study, which was 95% of our goal. Retention in the study was high (101 of 108 recruited [94%] completed the study), and compliance with detailed physical activity assessments was good (e.g., average number of 24-hr recalls was 13.0 [SD=1.6]). Fifty-six percent of the participants completing the study were women, and African American's represent 35% of the overall sample. Results from work in Aim 2 led to the selection of a three-item physical activity survey that asks about moderate and vigorous physical activities done at home, at work, and during leisure-time. Selection of the final three-item survey for administration in the national survey (Aim 3) was determined through consultation with the original SIP13 investigative team, Carol Macera, Ph.D., and collaborators on CDC's physical activity surveillance team.

Aim 3. The national survey was initiated by the University of South Carolina Survey Research Laboratory in March 2003 and completed in October of that year. A total of 3322 interviews were completed. Twenty-eight percent of all respondents report African-American ethnicity. As expected, representation of men in the sample was lower than women (36% and 64%, respectively). We are in the process of evaluating the results from the national survey.

Aim 4. Dissemination of SIP13 results is underway. A manuscript describing the results of Aim 2 will be submitted for peer review in September 2004. In addition, Dr. Matthews plans to submit an abstract in November 2004 for presentation at a national professional conference. Analysis of the national survey data obtained to complete aim three is underway and manuscript preparation is on track for completion by the end of the year.