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:Consistent with our results, there was no significant association of 25(OH)D and mortality in a 3-year follow-up study of 230 Chinese patients with a median peritoneal dialysis duration of 26 months [7].
Category: