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:In accordance with other studies our analysis found that diabetes [6,10], COPD [2,19], impaired preoperative kidney function [4,20], and obesity [2,4,6,9,12] to be independent risk factors for mediastinitis.
Category: