Evaluate the collective function of references cited together in a given text segment.
Classify their combined role into one of the following categories: 'method', 'background', or 'result'.

Text:Similar results have been obtained by a study performed in the North Indian population (31), which found that the genotypes MMP-2 (CT) and TIMP-2 (GC) increased genetic tendency towards prostate cancer by 1.
Category: