Reporting of systematic reviews of micronutrients and health: a critical appraisal

Am J Clin Nutr. 2009 Apr;89(4):1099-113. doi: 10.3945/ajcn.2008.26821. Epub 2009 Feb 25.


Background: The quality of nutrition-related systematic reviews (SRs) is an unstudied but important factor affecting their usefulness.

Objectives: The objectives were to evaluate the reporting quality of published SRs and to identify areas of improvement.

Design: Descriptive and exploratory analyses of the reporting quality (7 nutrition items and 28 SR reporting items) of all English-language SRs published through July 2007 linking micronutrients and health outcomes in humans were conducted. Factors that may be associated with reporting quality were also evaluated.

Results: We identified 141 eligible SRs of 21 micronutrients. Ninety SRs that included only interventional studies met a higher proportion of our reporting criteria (median: 62%; interquartile range: 51%, 72%) than did 31 SRs with only observational studies (median: 53%; interquartile range: 47%, 60%) or 20 SRs with both study designs (median: 47%; interquartile range: 39%, 52%) (P < 0.001). SRs published after consensus reporting standards (since 2003) met a higher proportion of the reporting criteria than did earlier SRs (median: 59% compared with 50%; P = 0.01); however, the reporting of nutrition variables remained unchanged (median: 38% compared with 33%; P = 0.7). The least-reported nutrition criteria were baseline nutrient exposures (28%) and effects of measurement errors from nutrition exposures (24%). Only 58 SRs (41%) used quality scales or checklists to assess the methodologic quality of the primary studies included.

Conclusions: The reporting quality of SRs has improved 3 y after publication of SR reporting standards, but the reporting of nutrition variables has not. Improved adherence to consensus methods and reporting standards should improve the utility of nutrition SRs.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Bias
  • Biomedical Research / standards*
  • Biomedical Research / statistics & numerical data
  • Epidemiology
  • Evidence-Based Medicine
  • Health Services Research / standards*
  • Health Services Research / statistics & numerical data
  • Health Status*
  • Humans
  • Micronutrients / administration & dosage*
  • Periodicals as Topic
  • Research Design
  • Review Literature as Topic*


  • Micronutrients