A Racial Comparison of Differences between Self-Reported and Objectively Measured Physical Activity among US Adults with Diabetes.

Objective: To investigate: 1) the racial/ethnic disparities in meeting the recommended physical activity as measured by subjective vs objective measures in a national sample of individuals with type 2 diabetes mellitus; and 2) the racial/ethnic differences with respect to the magnitude of the discrepancy between self-reported and objectively measured moderate-to-vigorous intensity aerobic physical activity (MVPA). Methods: We used data from the National Health and Nutrition Examination Survey (NHANES) 2003-06 to calculate and compare the percentage of individuals with diabetes who achieved the recommended levels of physical activity as measured by subjective self-report (500 metabolic equivalents (MET)-minutes/week) and objective accelerometer measurement (150 minutes per week of MVPA) across racial/ethnic groups. Results: 71.2%, 15.7%, and 13.1% of participants were White, African American, and Hispanic, respectively. Based on self-report, 67.1%, 39.2%, and 55.1% of Whites, African Americans, and Hispanics, respectively, met the 500 MET-minutes/week threshold of physical activity (P<.0001). Objective measurement by accelerometer showed that 44.2%, 42.6%, and 65.1% of Whites, African Americans, and Hispanics, respectively, met the threshold (P<.0003). Conclusions: Many individuals with type 2 diabetes mellitus did not meet the recommended physical activity thresholds. African Americans had the lowest proportion of meeting both the self-reported and objectively measured thresholds. White patients with diabetes overestimated frequency of their physical activity, while their Hispanic counterparts significantly underestimated it. Also, the gap between the two measures of MVPA was largest among Hispanics.