Abstract
The food frequency questionnaire (FFQ) is known to be prone to measurement error. Researchers have suggested excluding implausible energy reporters (IERs) of FFQ total energy when examining the relationship between a health outcome and FFQ-reported intake to obtain less biased estimates of the effect of the error-prone measure of exposure; however, the statistical properties of stratifying by IER status have not been studied. Under certain assumptions, including nondifferential error, we show that when stratifying by IER status, the attenuation of the estimated relative risk in the stratified models will be either greater or less in both strata (implausible and plausible reporters) than for the nonstratified model, contrary to the common belief that the attenuation will be less among plausible reporters and greater among IERs. Whether there is more or less attenuation depends on the pairwise correlations between true exposure, observed exposure, and the stratification variable. Thus exclusion of IERs is inadvisable but stratification by IER status can sometimes help. We also address the case of differential error. Examples from the Observing Protein and Energy Nutrition Study and simulations illustrate these results.
Original language | English |
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Pages (from-to) | 1538-1551 |
Number of pages | 14 |
Journal | Biometrical Journal |
Volume | 58 |
Issue number | 6 |
DOIs | |
State | Published - 1 Nov 2016 |
Externally published | Yes |
Bibliographical note
Publisher Copyright:© 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim
Funding
This work was supported by the National Cancer Institute at the National Institutes of Health (P30 CA012197 for J.A.T. and U01 CA057030 for R.J.C.).
Funders | Funder number |
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National Institutes of Health | U01 CA057030 |
National Cancer Institute | P30CA012197 |
Keywords
- Attenuation
- Bias (epidemiology)
- Food frequency questionnaire
- Models
- Statistical
- Underreporting