Addressing measurement error in diet assessment in the Women's Health Initiative: the use of biomarker-based calibration to mitigate measurement error

Oregon Convention Center 

Self-report dietary data are prone to both systematic and random sources of measurement error, impacting both the monitoring of nutritional status in the population and quantifying diet-disease relationships, making diet a difficult exposure to study. Researchers from the Women's Health Initiative (WHI) have conducted biomarker studies and calibration studies nested within WHI to be able to use statistical methods to adjust for measurement error. In addition to measurement error, dietary data are prone to skewness and excess zeroes in some cases, which must also be addressed. Using examples from WHI, the impact of measurement error on power and paramter estimates will be described, and techniques for mitigating this error will be illustrated, including both study design and statistical methods.