THE ROLE OF MULTICENTER COHORT STUDIES IN STUDYING THE RELATION BETWEEN DIET AND CANCER

In spite of important progress made during recent decades in nutrition al epidemiology methods, many questions about the role of diet in dete rmining dancer risk remain elusive. One example of an unresolved quest ion is whether a high percentage of energy intake in the form of fat ( especially saturated fat) is associated with an increased risk of brea st cancer. Observations from international correlation and case-contro l studies support this hypothesis, while results from prospective coho rt studies, generally considered less prone to bias, do not. In this p aper, we review the advantages and limitations of these different type s of epidemiological study design, and discuss how multi-centre studie s may help answer some of the unresolved questions about relations bet ween diet, nutritional status, and cancer risk. Multi-centre cohort st udies may have the advantage of increased statistical power because of larger variations in individuals' dietary intake patterns and disease risk (as in international correlation studies), while at the same tim e offering all the possibilities of individual-level studies to model confounding and/or interaction effects. (C) 1997 Elsevier Science Irel and Ltd.