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Macdonald TM, Mackenzie IS, Wei L, Hawkey CJ, Ford I; SCOT study group collaborators.Macdonald TM, et al.BMJ Open. 2013 Jan 29;3(1):e002295. doi: 10.1136/bmjopen-2012-002295.BMJ Open. 2013.PMID: 23364320Free PMC article.