Multilevel modeling in epidemiology with GLIMMIX

Previous work has shown that multilevel modeling can be a valuable techniqu e for epidemiologic analysis. The complexity of using this approach, howeve r, continues to restrict its general application. A critical factor is the lack of flexible and appropriate software for multilevel modeling. SAS prov ides a macro, GLIMMIX, that can be used for multilever modeling, but that i s not sufficient for a complete epidemiologic analysis. We here provide add itional code to obtain epidemiologic output from GLIMMIX, illustrated with new data on diet and breast cancer from the European Community Multicenter Study on Antioxidants, Myocardial Infarction, and Breast Cancer (EURAMIC). Our results give epidemiologists an easily used tool for fitting multilevel models.