Measurement error from assessing use of vitamin supplements at one point in time

Epidemiology. 1998 Sep;9(5):567-9.


Although many epidemiologic studies ask about current use of vitamin supplements, long-term use is usually the exposure of etiologic interest. We conducted a mailed survey to investigate the relation between current and long-term (10-year) supplement use (N = 325 adults). Estimates of current daily intake for supplemental micronutrients were roughly twice that of average daily intake over the past 10 years. Correlations between current intake and long-term intake from supplements alone were 0.77, 0.75, and 0.65 for vitamin C, vitamin E, and calcium, respectively. A measure of supplement use at one point in time incorporates measurement error that will attenuate measures of association.

MeSH terms

  • Aged
  • Diet / statistics & numerical data
  • Dietary Supplements / statistics & numerical data*
  • Epidemiologic Measurements
  • Epidemiologic Methods
  • Female
  • Humans
  • Male
  • Middle Aged
  • Nutrition Assessment*
  • Random Allocation
  • Surveys and Questionnaires
  • Vitamins / administration & dosage*
  • Washington / epidemiology


  • Vitamins