Syddall H E, Aihie Sayer A, Dennison E M, Martin H J, Barker D J P, Cooper C
MRC Epidemiology Resource Centre, University of Southampton, Southampton General Hospital, Southampton SO16 6YD, UK.
Int J Epidemiol. 2005 Dec;34(6):1234-42. doi: 10.1093/ije/dyi127. Epub 2005 Jun 17.