Characterizing Measurement Error in Dietary Sodium in Longitudinal Intervention Studies

Background: Previous measurement error work that investigates the relationship between a nutritional biomarker and self-reported intake levels has typically been at a single time point, in a single treatment group, or with respect to basic patient demographics. Few studies have examined the measurem...

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Main Authors: Adam Pittman, Elizabeth A. Stuart, Juned Siddique
Format: Article
Language:English
Published: Frontiers Media S.A. 2020-11-01
Series:Frontiers in Nutrition
Subjects:
Online Access:https://www.frontiersin.org/articles/10.3389/fnut.2020.581439/full
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author Adam Pittman
Elizabeth A. Stuart
Elizabeth A. Stuart
Juned Siddique
author_facet Adam Pittman
Elizabeth A. Stuart
Elizabeth A. Stuart
Juned Siddique
author_sort Adam Pittman
collection DOAJ
description Background: Previous measurement error work that investigates the relationship between a nutritional biomarker and self-reported intake levels has typically been at a single time point, in a single treatment group, or with respect to basic patient demographics. Few studies have examined the measurement error structure in longitudinal randomized trials, and whether the error varies across time or group. This structure is crucial to understand, however, in order to correct for measurement error in self-reported outcomes and properly interpret the longitudinal effects of dietary interventions.Methods: Using two longitudinal randomized controlled trials with internal longitudinal validation data (urinary biomarkers and self-reported values), we examine the relationship between urinary sodium and self-reported sodium and whether this relationship changes as a function of time and/or treatment condition. We do this by building a mixed effects regression model, allowing for a flexible error variance-covariance structure, and testing all possible interactions between time, treatment condition, and self-reported intake.Results: Using a backward selection approach, we arrived at the same final model for both validation data sets. We found no evidence that measurement error changes as a function of self-reported sodium. However, we did find evidence that urinary sodium can differ by time or treatment condition even when conditioning on self-reported values.Conclusion: In longitudinal nutritional intervention trials it is possible that measurement error differs across time and treatment groups. It is important for researchers to consider this possibility and not just assume non-differential measurement error. Future studies should consider data collection strategies to account for the potential dynamic nature of measurement error, such as collecting internal validation data across time and treatment groups when possible.
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spelling doaj.art-92d5b3456b6e41aca3d689173736d56b2022-12-21T22:08:44ZengFrontiers Media S.A.Frontiers in Nutrition2296-861X2020-11-01710.3389/fnut.2020.581439581439Characterizing Measurement Error in Dietary Sodium in Longitudinal Intervention StudiesAdam Pittman0Elizabeth A. Stuart1Elizabeth A. Stuart2Juned Siddique3Department of Biostatistics, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, United StatesDepartment of Biostatistics, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, United StatesDepartment of Mental Health, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, United StatesDepartment of Preventive Medicine, Northwestern University Feinberg School of Medicine, Chicago, IL, United StatesBackground: Previous measurement error work that investigates the relationship between a nutritional biomarker and self-reported intake levels has typically been at a single time point, in a single treatment group, or with respect to basic patient demographics. Few studies have examined the measurement error structure in longitudinal randomized trials, and whether the error varies across time or group. This structure is crucial to understand, however, in order to correct for measurement error in self-reported outcomes and properly interpret the longitudinal effects of dietary interventions.Methods: Using two longitudinal randomized controlled trials with internal longitudinal validation data (urinary biomarkers and self-reported values), we examine the relationship between urinary sodium and self-reported sodium and whether this relationship changes as a function of time and/or treatment condition. We do this by building a mixed effects regression model, allowing for a flexible error variance-covariance structure, and testing all possible interactions between time, treatment condition, and self-reported intake.Results: Using a backward selection approach, we arrived at the same final model for both validation data sets. We found no evidence that measurement error changes as a function of self-reported sodium. However, we did find evidence that urinary sodium can differ by time or treatment condition even when conditioning on self-reported values.Conclusion: In longitudinal nutritional intervention trials it is possible that measurement error differs across time and treatment groups. It is important for researchers to consider this possibility and not just assume non-differential measurement error. Future studies should consider data collection strategies to account for the potential dynamic nature of measurement error, such as collecting internal validation data across time and treatment groups when possible.https://www.frontiersin.org/articles/10.3389/fnut.2020.581439/fulllifestyle interventionmeasurement errornutritionsodium intakebiomarkersself-reporting habits
spellingShingle Adam Pittman
Elizabeth A. Stuart
Elizabeth A. Stuart
Juned Siddique
Characterizing Measurement Error in Dietary Sodium in Longitudinal Intervention Studies
Frontiers in Nutrition
lifestyle intervention
measurement error
nutrition
sodium intake
biomarkers
self-reporting habits
title Characterizing Measurement Error in Dietary Sodium in Longitudinal Intervention Studies
title_full Characterizing Measurement Error in Dietary Sodium in Longitudinal Intervention Studies
title_fullStr Characterizing Measurement Error in Dietary Sodium in Longitudinal Intervention Studies
title_full_unstemmed Characterizing Measurement Error in Dietary Sodium in Longitudinal Intervention Studies
title_short Characterizing Measurement Error in Dietary Sodium in Longitudinal Intervention Studies
title_sort characterizing measurement error in dietary sodium in longitudinal intervention studies
topic lifestyle intervention
measurement error
nutrition
sodium intake
biomarkers
self-reporting habits
url https://www.frontiersin.org/articles/10.3389/fnut.2020.581439/full
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AT elizabethastuart characterizingmeasurementerrorindietarysodiuminlongitudinalinterventionstudies
AT junedsiddique characterizingmeasurementerrorindietarysodiuminlongitudinalinterventionstudies