Methods and Applications of Statistics in Clinical Trials, Volume 1: Concepts, Principles, Trials, and Designs

Chapter 78

Women’s Health Initiative Dietary Modification Trial: Update and Application of Biomarker Calibration to Self-Report Measures of Diet and Physical Activity

Y. Mossavar-Rahmani, L. F. Tinker, M. L. Neuhouser, Y. Huang, P. Shaw, J. M. Beasley, C. Di, C. Zheng, W. Li, and R. L. Prentice

78.1 Rationale for Biomarker Calibration of Self-Report Measures of Diet

Evidence has been accruing that self-reported dietary intake underestimates actual intake. Particularly noteworthy is that overweight and obese persons may systematically underreport energy intake [1–3]. Women who, at Women’s Health Initiative (WHI) enrollment during 1993–1998, were in their 50s underreported energy intake to a greater degree than women who were in their 70s, and there is some evidence that Black or Hispanic women may underreport energy intake to a greater degree than White women [1, 2]. Protein intake was also under-reported although to a lesser extent than energy, which resulted in a modest overestimation of protein density (% energy from protein). Numerous reasons may exist for this underreporting including social desirability [4,5], bias relating to recall or potentially an inadequate representation of regional or cultural foods when limited choice food frequency questionnaires (FFQs) are used as the assessment instruments.

Given this background and impetus from the Observing Protein and Energy Nutrition Study (OPEN) study [3], WHI investigators launched two biomarker studies: the Nutrient Biomarker ...