title: Considering the value of dietary assessment data in informing nutrition-related health policy.
abstract: Dietary assessment has long been known to be challenged by measurement error. A substantial amount of literature on methods for determining the effects of error on causal inference has accumulated over the past decades. These methods have unrealized potential for improving the validity of data collected for research studies and national nutritional surveillance, primarily through the NHANES. Recently, the validity of dietary data has been called into question. Arguments against using dietary data to assess diet-health relations or to inform the nutrition policy debate are subject to flaws that fall into 2 broad areas: 1) ignorance or misunderstanding of methodologic issues; and 2) faulty logic in drawing inferences. Nine specific issues are identified in these arguments, indicating insufficient grasp of the methods used for assessing diet and designing nutritional epidemiologic studies. These include a narrow operationalization of validity, failure to properly account for sources of error, and large, unsubstantiated jumps to policy implications. Recent attacks on the inadequacy of 24-h recall-derived data from the NHANES are uninformative regarding effects on estimating risk of health outcomes and on inferences to inform the diet-related health policy debate. Despite errors, for many purposes and in many contexts, these dietary data have proven to be useful in addressing important research and policy questions. Similarly, structured instruments, such as the food frequency questionnaire, which is the mainstay of epidemiologic literature, can provide useful data when errors are measured and considered in analyses.
authors.affiliation: Departments of Epidemiology and Biostatistics and Cancer Prevention and Control Program, and Center for Research in Nutrition and Health Disparities, University of South Carolina, Columbia, SC; jhebert@sc.edu.
authors.forename: James R
authors.initials: JR
authors.lastname: Hébert
authors.affiliation: Departments of Epidemiology and Biostatistics and.
authors.forename: Thomas G
authors.initials: TG
authors.lastname: Hurley
authors.affiliation: Departments of Epidemiology and Biostatistics and Cancer Prevention and Control Program, and Center for Research in Nutrition and Health Disparities, University of South Carolina, Columbia, SC;
authors.forename: Susan E
authors.initials: SE
authors.lastname: Steck
authors.affiliation: Department of Health Policy and Management, Boston University School of Public Health, Boston, MA; Center for Healthcare Organization and Implementation Research, Bedford Veterans Affairs Medical Center, Bedford, MA;
authors.forename: Donald R
authors.initials: DR
authors.lastname: Miller
authors.affiliation: Departments of Epidemiology and Biostatistics and Cancer Prevention and Control Program, and.
authors.forename: Fred K
authors.initials: FK
authors.lastname: Tabung
authors.affiliation: Human Nutrition Program, Department of Environmental Health Sciences, School of Public Health and Center for Human Growth and Development, University of Michigan, Ann Arbor, MI; Department of Nutrition, Harvard School of Public Health, Boston, MA.
authors.forename: Karen E
authors.initials: KE
authors.lastname: Peterson
authors.affiliation: Division of Research, Kaiser Permanente Northern California, Oakland, CA; and School of Medicine, University of California, Davis, Sacramento, CA.
authors.forename: Lawrence H
authors.initials: LH
authors.lastname: Kushi
authors.affiliation: Health Promotion, Education, and Behavior, Arnold School of Public Health, Center for Research in Nutrition and Health Disparities, University of South Carolina, Columbia, SC;
authors.forename: Edward A
authors.initials: EA
authors.lastname: Frongillo
mesh_terms: D004032:Diet; D004034:Diet Surveys; D016021:Epidemiologic Studies; D006262:Health; D006801:Humans; D015596:Nutrition Assessment; D018673:Nutrition Policy; D009752:Nutritional Status