PREDICTION OF TOTAL ENERGY EXPENDITURE AND MODERATE-TO-VIGOROUS PHYSICAL ACTIVITY BY THE NHANES PAQ

R.P. McGrath*, A.J. Moshfegh**, M. Kramer**, W.V. Rumpler**, D.J. Baer**, C.A. Vella*, P.W. Scruggs*, & D.R. Paul* *University of Idaho, Moscow, ID; **U.S. Department of Agriculture, Beltsville Human Nutrition Research Center, Beltsville, MD The NHANES physical activity questionnaire (PAQ) is a popular self-report method for measuring physical activity, although the validity of total energy expenditure (TEE) and moderate-to-vigorous physical activity (MVPA) estimates have yet to be validated. PURPOSE: To compare estimates of TEE (TEE-PAQ) and MVPA (MVPA-PAQ) from the NHANES PAQ with TEE via doubly labeled water (TEE-DLW), and total physical activity (TPA) and MVPA (MVPA-A) via accelerometer. METHODS: 244 women (age 49.2 ±10.8 yrs. and BMI 26.2 ± 4.85 kg/m2) and 242 men (age 49.7 ±11.0 yrs. and BMI 26.7 ± 4.08 kg/m2) completed the NHANES PAQ (2001 version). TEE was measured by the doubly labeled water technique over a 2-week period. TPA and MVPA-A were measured via accelerometer for a minimum of 7 days. T-tests were conducted to compare differences between TEE-PAQ and TEE-DLW, and MVPA-PAQ and MVPA-A. To compare the predictions of TEE-PAQ and TEE-DLW, regression analyses were conducted utilizing TPA and body weight as independent variables. RESULTS: TEE-PAQ (9.61 ± 2.60 MJ/d) was significantly lower than TEE-DLW (10.6 ± 2.38 MJ/d) (pThese data indicate that the NHANES PAQ underestimates TEE when compared to doubly labeled water (1.0 MJ/d), with a large amount of variability present (2.17 MJ/d on average per subject). The lower residual variance in the comparison between TEE-DLW and TPA (when compared to TEE-PAQ and TPA) indicate that TEE-PAQ may be the less valid approach. Similarly the PAQ overestimates MVPA by 11.2 min/d when compared to accelerometry, with an average error of 21.1 min/d per subject. Therefore, estimates of TEE and MVPA from the NHANES PAQ should be interpreted with caution. This study was funded by the USDA