OBJECTIVETo explore the application of counter-matching design in epidemiological research.

METHODSThrough elaboration of the study about gene-environment interactions in the etiology of breast cancer, methodology regarding counter-matching design and statistic methods was introduced.

RESULTSThis design improved the potential for detecting gene-environment interactions for diseases when both gene mutations and the environmental exposures of interest were rare in the general population.

CONCLUSIONCounter-matching appearsed to be more appropriate than most traditional epidemiologic methods for the study of interactions involving rare factors.