Diet, Nutrition, and Cancer Directions for Research (1983) / Chapter Skim
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4. Epidemiological Methods
4. Epidemiological Methods
Pages 12-18
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From page 12... ...
diet recalls Diet histories Biochemical markers of exposure Anthropometric measurements These approaches and their respective strengths and limitations were described in detail in Chapter 3 of the first report by the Committee on Diet, Nutrition, and Cancer (National Research Council, 1982~. The following paragraphs summarize methodological problems that characterize epidemiological studie s of diet and cancer and provide suggestions for research.
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From page 13... ...
Unfortunately, few markers that reflect longterm dietary exposures have yet been identified, since the concentrations of substances in biological fluids such as serum and urine are usually related to recent exposures or to the functioning of ho~eostatic control mechanisms rather than to long-term intakes and body stores. In another method, certain anthropometric measures known to be correlated with obesity (including indices based on height and weight or skinfold thickness)
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From page 14... ...
Moreover, current approaches to dietary data collection are generally based on the subjects' recollection of food items consumed, not their constituents, whereas most of the hypotheses being tested pertain to nutritive or nonnutritive food components. Since all foods are collections of such components, it has not been possible to relate the findings in epidemiological studies specifically to single constituents of foods.
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From page 15... ...
Research in this area should include a search for new aids to facilitate individual recalls and should enlist the participation of specialists in human behavior and psychometric measurement, who might be able to identify the best ways to elicit accurate information and to provide new insight into the factors that influence the responses of people asked to describe their diets. In addition, a search should be conducted for biochemical markers that reflect relevant dietary exposures some time in the remote past.
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From page 16... ...
Whenever possible, these studies should be based on exposure data collected directly from individuals rather than on per-capita consumption estimates. When sufficient information is available, they should also be based on morbidity rather than on mortality data, since the latter are influenced by survival patterns and can be misleading (National Research Council, 1982~.
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From page 17... ...
This is the most suitable approach for investigations based on biochemical indicators of dietary exposures. Cohort studies are best carried out in populations at high risk for diet-associated cancers, where representative dietary data can be readily obtained and where long-term followup can be aided by population-based cancer registries and good vital statistics data for end points.
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From page 18... ...
Moreover, since many of the dietary and nondietary factors in studies on cancer are highly intercorrelated, efforts should be made to explore statistical methods that are less sensitive to collinearity than is multiple logistic regression analysis. Fi nally, statistical techniques need to be developed to describe snore accurately the various forms of interaction among dietary variables.
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