title: Retrospective Studies.
authors.affiliation: Vascular Surgery Research Group, Imperial College, London W6 8RP, UK. Electronic address: j.powell@imperial.ac.uk.
authors.forename: J T
authors.initials: JT
authors.lastname: Powell
authors.affiliation: Department of Public Health and Primary Care, University of Cambridge, Cambridge CB1 8RN, UK.
authors.forename: M J
authors.initials: MJ
authors.lastname: Sweeting
mesh_terms: D006801:Humans; D012189:Retrospective Studies