Max_r: an optimal method for the selection of subsets of foods for the measurement of specific nutrient exposures.

Max_r, a new method of food subset selection for the measurement of specific nutrient exposures, is programmed. Frequently, epidemiologic questionnaires are designed to measure several individual level exposures, including exposure to one or more nutrients. Although most nutrients are contained in a large number of foods, constraints on questionnaire size allow inclusion of only a subset of these. When nutrient exposure as measured in a subset of foods will be used to estimate the effect of the nutrient on disease risk with a logistic regression model, max_r is the optimal method of choosing the subset. Various aspects of the program are illustrated with a numerical example measuring dietary protein intake. The executable version of this Fortran program for IBM compatible PCs requires 3Mb of memory. It is available (along with complete documentation, test data and output) via e-mail from thomasd@epndce.nci.nih.gov or upon submission of a diskette formatted for MS-DOS.