Evidence-based nutrition - review of nutritional epidemiological studies

Abstract

Results from epidemiological studies are often used to explore the relationships between nutrition and health. The objective of this paper is to provide guidelines for evaluating the quality and strength of evidence from different types of epidemiological studies (including ecological, cross-sectional, case-control, cohort and experimental studies) for conclusions about the relationship between nutrition and health. The discussion include advantages and disadvantages of these different types of studies, exposures, outcomes, the role of chance, bias and confounding factors, recruitment and sampling procedures and criteria, study size and power, measurement error (random and systematic), time effects, observer and participant effects, compliance, as well as analysis and interpretation of results. A checklist for reviewing epidemiological studies is given as guide to assess the quality of the data and the suitability of the study results for specific conclusions.