title: Multimorbidity patterns are differentially associated with functional ability and decline in a longitudinal cohort of older women.
abstract: BACKGROUND
  we aimed to identify multimorbidity patterns and relate these patterns to functional ability and decline.
  
  
  METHODS
  we included 7,270 participants of the older cohort of the Australian Longitudinal Study on Women's Health, who were surveyed every 3 years from 2002 to 2011. We used factor analysis to identify multimorbidity patterns from 31 self-reported chronic conditions among women aged 76-81 in 2002. We applied a linear increments model to account for attrition and related the multimorbidity patterns to functional ability and decline at subsequent surveys, as measured by activities of daily living (ADL) and instrumental activities of daily living (IADL). For each pattern, we determined mean ADL and IADL scores in the middle and highest third of factor score in comparison to a reference group.
  
  
  RESULTS
  we identified three multimorbidity patterns, labelled musculoskeletal/somatic (MSO), neurological/mental health (NMH) and cardiovascular (CVD). High factor scores for NMH, MSO and CVD were associated with significantly higher mean ADL and IADL scores (poorer functional ability) in 2005 compared with the reference group of low factor scores for all three factors. The CVD pattern was associated with the greatest decline in ADL between 2005 and 2011, whereas the NMH pattern was associated with the greatest decline in IADL.
  
  
  CONCLUSIONS
  distinct multimorbidity patterns were differentially associated with functional ability and decline. Given the paucity of studies on multimorbidity patterns, future studies should seek to assess the reproducibility of our findings in other populations and settings, and investigate the potential implications for improved prediction of functional decline.
authors.affiliation: School of Public Health, University of Queensland, Brisbane, QLD 4006, Australia.
authors.forename: Caroline A
authors.initials: CA
authors.lastname: Jackson
authors.affiliation: School of Public Health, University of Queensland, Brisbane, QLD 4006, Australia.
authors.forename: Mark
authors.initials: M
authors.lastname: Jones
authors.affiliation: School of Public Health, University of Queensland, Brisbane, QLD 4006, Australia.
authors.forename: Leigh
authors.initials: L
authors.lastname: Tooth
authors.affiliation: School of Public Health, University of Queensland, Brisbane, QLD 4006, Australia.
authors.forename: Gita D
authors.initials: GD
authors.lastname: Mishra
authors.affiliation: University of Newcastle-Research Centre for Gender, Health and Ageing, The University of Newcastle Callaghan, Newcastle, NSW 2308, Australia.
authors.forename: Julie
authors.initials: J
authors.lastname: Byles
authors.affiliation: School of Public Health, University of Queensland, Brisbane, QLD 4006, Australia.
authors.forename: Annette
authors.initials: A
authors.lastname: Dobson
mesh_terms: D000203:Activities of Daily Living; D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D000375:Aging; D001315:Australia / Q000453:epidemiology; D002908:Chronic Disease; D015897:Comorbidity; D005163:Factor Analysis, Statistical; D005260:Female; D015577:Geriatric Assessment; D006304:Health Status; D006801:Humans; D016014:Linear Models; D008137:Longitudinal Studies; D012307:Risk Factors; D013997:Time Factors
keywords: ageing; chronic disease; co-morbidity; disability; multimorbidity; older people