AS218 - Nutrition and Physical Activity Assessment Study (NPAAS)

This page is intended to provide a study summary of WHI AS218 (R01 CA119171). See W27-NPAAS Lab Work (WHI Core) for specimen assay details on NPAAS.

Investigator Names and Contact Information

Ross Prentice, PhD, FHCRC,


This proposal requested support for a Nutrition and Physical Activity Assessment Study (NPAAS) within the Observational Study (OS) component of the Women’s Health Initiative (WHI). The NPAAS was conducted among 450 postmenopausal weight-stable women who are representative of OS women in age, body mass, and ethnicity. Participating women will provide the same food frequency questionnaire (FFQ) and physical activity questionnaire used at time of screening for WHI enrollment (1993-1998) in addition to other selected dietary and physical activity assessments.

Additionally, participating women followed a doubly-labeled water protocol to objectively assess total energy expenditure and an indirect calorimetry protocol to assess resting energy expenditure, thereby also yielding an objective assessment of activity-related energy expenditure. The expenditure of protein, sodium, and potassium were also assessed from urine specimens, and the concentrations of various nutrients will be measured in blood specimens.

These data are being used to evaluate and contrast measurement properties of carefully selected dietary and physical activity assessment tools and their combination, with an emphasis on: systematic bias as a function of body mass, ethnicity, age, and other individual characteristics; the magnitude of person-specific measurement errors; the correlation patterns among errors from differing assessment procedures; and the precision of nutrient consumption and activity-related energy expenditure estimates. Additionally, the NPAAS data are being used to calibrate the FFQ and physical activity questionnaire data collected at baseline, and subsequently, in the WHI, for use in a range of analyses to associate dietary and physical activity patterns with weight change and disease risk over an average 10-year follow-up period.


The overall aim of this proposal is to identify improved tools and methods for assessing individual diet and physical activity. Established biomarkers of total, activity-related, and protein, energy expenditure, as well as sodium and potassium expenditure, will provide the centerpiece for this effort, as these biomarkers plausibly adhere to a classical measurement model, and hence can be used to calibrate assessments that are practical in large-scale field studies, primarily self-report assessments. Blood concentrations of various nutrients will supplement these ‘recovery’ biomarkers. The overall aim will be achieved through the following five specific aims:

  1. To collect objective measures of total and resting energy expenditure; protein, sodium, and potassium expenditure; and selected micronutrient blood concentrations on a representative sample of 450 women from the Women’s Health Initiative Observational Study.
  2. To collect concurrent Food Frequency Questionnaire (FFQ), 4-Day Food Record (4DFR), and 24-hour Dietary Recall (2 week days and one weekend day) data.
  3. To collect questionnaire physical activity data using the WHI Personal Habits Questionnaire, as well as Physical Activity Frequency Questionnaire (adapted from University of Arizona questionnaire) and Physical Activity Recall (recall of previous 7 days) data, in this same group of women.
  4. Using appropriate measurement models and statistical methods to examine the measurement properties of estimates of total, protein, and activity-related, energy expenditure arising from these measurement tools and their combination. The measurement property evaluation will emphasize the dependence of measurement error on study subject characteristics, person-specific biases, and overall precision.
    Correlations of measurement errors between assessment instruments will also be examined. Recovery biomarkers of sodium and potassium expenditure and blood concentrations of various nutrients will also be used to assess self-report measurement properties. Measurement properties will be examined in relation to participant ethnicity, body mass, and other important characteristics.
  5. To produce biomarker-calibrated estimates of total energy consumption, absolute consumption of various nutrients, and of activity-related energy expenditure for use in a range of analyses of weight change and disease occurrence in the WHI. The calibration procedure will allow ethnicity, body mass, and age to affect the self-report adjustments. 


Some of the publications related to this ancillary study are:  

Ms1178 (Methods, Diet)- Prentice RL, Mossavar-Rahmani Y, Huang Y, Van Horn L, Beresford SA, Caan B, Tinker L, Schoeller D, Bingham S, Eaton CB, Thomson C, Johnson KC, Ockene J, Sarto G, Heiss G and Neuhouser ML. Evaluation and comparison of food records, recalls, and frequencies for energy and protein assessment by using recovery biomarkers. Am J Epidemiol. 2011 Jul 15. [Epub ahead of print]

Ms1385 (Methods, Physical Activity)- Neuhouser ML, Di C, Tinker LF, Thomson C, Sternfeld B, Mossavar-Rahmani Y, Stefanick ML, Sims S, Curb JD, Lamonte M, Seguin R, Johnson KC, Prentice RL. Physical activity assessment: biomarkers and self-report of activity-related energy expenditure in the Women’s Health Initiative. Am J Epidemiol. 2013 Mar 15;177(6):576-85. doi: 10.1093/aje/kws269. Epub 2013 Feb 22

Ms1532 (Methods, Psychosocial Characteristics)- Mossavar-Rahmani Y, Tinker LF, Huang Y, Neuhouser ML, McCann SE, Seguin RA, Vitolins MZ, Curb JD, Prentice RL. Factors relating to eating style, social desirability,body image and eating meals at home increase the precision of calibration equations correcting self-report measures of diet using recovery
biomarkers: findings from the Women’s Health Initiative. Nutr J. 2013 May 16;12(1):63. [Epub ahead of print]

A full listing of NPAAS- and NBS-related publications and presentations is available for viewing.  In addition, for a complete, up-to-date list of WHI papers related to this ancillary study, please use the searchable Bibliography section of this website. To search for papers by study number, access the Simple Search, and enter the study number in the “Related Studies” field.