Nutritional epidemiology studies within the EEB have increasingly relied on biochemical and anthropometric measurements to complement dietary interviews. In addition, they have modified food frequency instruments to better assess current dietary hypotheses and to reflect cognitive psychology research. Migrant and ethnic populations are often utilized because of the heterogeneity of dietary patterns. Molecular probes are identifying intermediates on the continuum between exposure and outcome. Several studies of breast and endometrial cancer are attempting to disentangle the roles of fat, calories, meat and dairy products, fatty acid composition, and other aspects of a westernized diet. Patterns of weight gain, body fat deposition, physical activity, alcohol consumption, and endogenous hormone levels are being investigated along with diet. The breast cancer studies distinguish between exposures during early reproductive life and later. Whether beta-carotene, other carotenoids, or other vegetable and fruit constituents explain the reduction in risk of many cancers consistently associated with increased vegetable and fruit intake is a major research focus. Various ways to integrate micronutrient intake from foods and supplements are being analyzed. Studies of cervical cancer, in the U.S. and in Latin America, are evaluating the protective role of micronutrients, specifically carotenoids, vitamin C, folate, and selenium, with emphasis on the stage of cervical carcinogenesis. Mutagens formed in cooking, specifically polyaromatic hydrocarbons and heterocyclic amines, and in food storage are being evaluated, along with the importance of metabolic activation and genetic susceptibility. Several methodologic studies have been developed to assess measurement errors and biases in dietary, anthropometric, nutrient, and hormone data.
