Gains in statistical power from using a dietary biomarker in combination with self-reported intake to strengthen the analysis of a diet-disease association: An example from CAREDS

Laurence S. Freedman, Natas̃a Tasevska, Victor Kipnis, Arthur Schatzkin, Julie Mares, Lesley Tinker, Nancy Potischman

Research output: Contribution to journalArticlepeer-review

37 Scopus citations

Abstract

A major problem in detecting diet-disease associations in nutritional cohort studies is measurement error in self-reported intakes, which causes loss of statistical power. The authors propose using biomarkers correlated with dietary intake to strengthen analyses of diet-disease hypotheses and to increase statistical power. They consider combining self-reported intakes and biomarker levels using principal components or a sum of ranks and relating the combined measure to disease in conventional regression analyses. They illustrate their method in a study of the inverse association of dietary lutein plus zeaxanthin with nuclear cataracts, using serum lutein plus zeaxanthin as the biomarker, with data from the Carotenoids in Age-Related Eye Disease Study (United States, 2001-2004). This example demonstrates that the combined measure provides higher statistical significance than the dietary measure or the serum measure alone, and it potentially provides sample savings of 8%-53% over analysis with dietary intake alone and of 6%-48% over analysis with serum level alone, depending on the definition of the outcome variable and the choice of confounders entered into the regression model. The authors conclude that combining appropriate biomarkers with dietary data in a cohort can strengthen the investigation of diet-disease associations by increasing the statistical power to detect them.

Original languageEnglish (US)
Pages (from-to)836-842
Number of pages7
JournalAmerican journal of epidemiology
Volume172
Issue number7
DOIs
StatePublished - Oct 1 2010
Externally publishedYes

Keywords

  • carotenoids
  • cataract
  • lutein
  • ranks
  • sample size

ASJC Scopus subject areas

  • General Medicine

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