Claire Gormley (UCD, Ireland)

Abstract. 

 Classical approaches to assessing dietary intake are associated with measurement error. In an effort to address inherent measurement error in dietary self-report data there is increased interest in the use of dietary biomarkers as objective measures of intake. Furthermore, there is a growing consensus of the need to combine dietary biomarker data with self-report data. A review of state of the art methods used to combine biomarker and self-report data is conducted.

Two predominant methods, the calibration method and the method of triads, emerge as being used to combine biomarker and self-report data when aiming to improve estimates of dietary intake. Both methods crucially assume measurement error independence. To expose and understand the performance of these methods in a range of realistic settings, their underpinning statistical concepts are explored and unified, and thorough simulation studies conducted.

Results show that violation of the methods' assumptions greatly influences resulting inference, but that this effect is mitigated in cases where the biomarker and self-report data are strongly indicative of the true intake. There is much scope for the further development of models and biomarkers in tandem to achieve the ultimate goal of accurately inferring true dietary intake.

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