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:Regarding the associations between the -634G[C polymorphism and hypertension, Lacchini et al. (2014) have reported that the variant genotypes of -634G[C SNP were associated with left ventricular hypertrophy in patients with systemic hypertension of Brazilian population.
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