Validation of the Arizona Activity Frequency Questionnaire using doubly labeled water

Purpose: Physical activity questionnaires (PAQs) are considered the most co st-efficient method to estimate total energy expenditure (TEE) in epidemiol ogical studies. However, relatively few PAQs have been validated using doub ly labeled water (DLW) in women or in samples with diverse ethnic backgroun ds. This study was conducted to validate the Arizona Activity Frequency Que stionnaire (AAFQ) for estimation of TEE and physical activity energy expend iture (PAEE) over 1 month using DLW as a reference method. Methods: Thirty- five relatively sedentary women completed the AAFQ before participating in an 8-d DLW protocol to measure TEE. TEE and PAEE were estimated from the AA FQ by calculating resting metabolic rate (RMR) using the equation of Miffli n et al. (AAFQ(mif)), by measuring RMR using indirect calorimetry (AAFQ(ic) ), and using MET conversion (AAFQ(met)). A predictive equation for TEE was generated. Results: The mean SD for TEE and PAEE from DLW were 9847 +/- 255 5 kJ.d(-1) and 5578 +/- 2084 kJ.d(-1), respectively. Formulas using RMR to calculate the TEE and PAEE from the AAFQ tended to underestimate TEE and PA EE, whereas those that included only weight tended to overestimate TEE and PAEE. On the basis of the Mifflin et al. equation, the AAFQ tends to undere stimate PAEE by 13%. This underestimation may be. explained by the low lean body mass of the sample population and by effectiveness of the METs/RMR ra tio in the obese. The following predictive equation was calculated: TEE (kJ .d(-1)) = (86.0 * average total daily MFTs) + (2.23 * RMRmif)-6726. When th e predictive equation is used, TEE calculated from the AAFQ is highly corre lated with DLW TEE (adjusted r(2) = 0.70, P<0.001). Conclusion: The AAFQ is an effective tool for the prediction of TEE and PAEE in epidemiological st udies.