title: Understanding the evolution of multimorbidity: evidences from the North West Adelaide Health Longitudinal Study (NWAHS).
abstract: OBJECTIVE
  The aim of this study is to describe the evolution of multimorbidity.
  
  
  METHODS
  Data from 1854 South Australians who participated in the North West Adelaide longitudinal Health Study (NWAHS) was collected between baseline (2000-2002) and follow-up (2008-2010). Status for eight chronic diseases (CDs) was determined by biomedical measurement or self-report. Chronic disease (CD) mean age of occurrence and order of appearance was investigated.
  
  
  RESULTS
  The prevalence of multimorbidity increased from 32% to 64% during the 7.8±1.1 years of follow-up. The estimated mean age of onset of a new CD was significantly older for hypertension, cardiovascular disease (CVD) and chronic obstructive pulmonary disease (COPD) and younger for hypercholesterolemia, asthma and other mental problem. Hypercholesterolemia was more likely to develop as a first than as a subsequent CD (39%vs.16%, p<0.0001) while CVD (1%vs.5%, p<0.0001), diabetes (5%vs.11%, p<0.001) and COPD (6%vs.16%, p<0.0001) were less likely. The presence of mood disorders at baseline was associated with an increased risk of developing other mental disorders (36%vs.12%, p<0.0001), diabetes (18%vs.9%, p<0.01) and asthma (30%vs.21%, p<0.05).
  
  
  CONCLUSIONS
  Longitudinal data could be used to study the evolution of multimorbidity and could provide information on CDs mean age of occurrence, order of appearance and impact on the development of future CDs.
authors.affiliation: Ministère de la Santé et des Services sociaux, Québec, Québec, Canada; Institut National de Santé Publique du Québec, Québec, Québec, Canada; Population Research and Outcome Studies, University of Adelaide, Adelaide, South Australia, Australia.
authors.forename: Guillaume
authors.initials: G
authors.lastname: Ruel
authors.affiliation: Bureau of Health Information, Chatswood, New South Wales, Australia; Centre de recherche du Centre hospitalier Universitaire de Montréal, Université de Montréal, Montréal, Québec, Canada.
authors.forename: Jean-Frédéric
authors.initials: JF
authors.lastname: Lévesque
authors.affiliation: Discipline of General Practice, University of Adelaide, Adelaide, South Australia, Australia.
authors.forename: Nigel
authors.initials: N
authors.lastname: Stocks
authors.affiliation: Institut National de Santé Publique du Québec, Québec, Québec, Canada; Département de science infirmière, Université du Québec à Rimouski, Rimouski, Québec, Canada.
authors.forename: Caroline
authors.initials: C
authors.lastname: Sirois
authors.affiliation: Institut National de Santé Publique du Québec, Québec, Québec, Canada; Département de pharmacie, Université Laval, Québec, Québec, Canada.
authors.forename: Edeltraut
authors.initials: E
authors.lastname: Kroger
authors.affiliation: Health Observatory, University of Adelaide, Adelaide, South Australia, Australia.
authors.forename: Robert J
authors.initials: RJ
authors.lastname: Adams
authors.affiliation: Institut National de Santé Publique du Québec, Québec, Québec, Canada; Faculté de Médecine, Université Laval, Québec, Québec, Canada.
authors.forename: Mariève
authors.initials: M
authors.lastname: Doucet
authors.affiliation: Population Research and Outcome Studies, University of Adelaide, Adelaide, South Australia, Australia.
authors.forename: Anne W
authors.initials: AW
authors.lastname: Taylor
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D002908:Chronic Disease / Q000453:epidemiology; D006801:Humans; D008137:Longitudinal Studies; D008875:Middle Aged; D009017:Morbidity / Q000639:trends*; D015995:Prevalence; D013021:South Australia / Q000453:epidemiology