Validation of the WHI brief physical activity questionnaire among women diagnosed with breast cancer

Objective: To investigate the psychometric properties of the physical activity (PA) measure of the Women's Health Initiative (WHI). Methods: Women diagnosed with breast cancer and enrolled in the Women's Healthy Eating and Living Study (average age 55 years) wore an accelerometer for 1 week and completed the 7-day Physical Activity Recall (PAR) and brief WHI measure. Results: Both self-reports correlated 0.73 with the accelerometer and had 100% sensitivity for meeting the current PA guideline, but specificity was significantly higher for the PAR. Conclusions: The WHI measure had comparable validity, sensitivity, and measurement bias compared to the widely accepted PAR.