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:Participants were monitored for deaths and hospital admissions using the Western Australian Data Linkage System.9
 For the present study, we excluded men with missing information on key variables (n=54); those with extreme SBP values (<80 or >250 mm Hg; n=6); those with a history of heart disease (n=3419) or stroke (n=1735) at baseline, to limit the effect of reverse causality; and those with an abdominal aortic aneurysm (‚â•30 mm in diameter) identified at screening (n=875) because these individuals are likely to have received medical intervention to address their risk of a major vascular event.
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