title: Somatic multimorbidity and self-rated health in the older population.
abstract: OBJECTIVE
  Chronic diseases are important predictors of self-rated health (SRH). This study investigated whether multimorbidity has a synergistic or cumulative impact on SRH. Moderation by gender and age was examined.
  
  
  METHODS
  Data originated from the Longitudinal Aging Study Amsterdam (N=2046, aged 57-98 years). We assessed the presence of lung disease, cardiac disease, peripheral atherosclerosis, stroke, diabetes mellitus, arthritis, and cancer. SRH was measured with the question "How is your health in general?" including 5 response categories. Generalized ordered probit models were applied; possible synergism was examined by testing for nonlinearity of the association.
  
  
  RESULTS
  The association between multimorbidity and SRH was nonlinear in that the effect of having a single disease was larger than the added effects of co-occurring diseases. However, from the second disease onward, each additional co-occurring disease caused cumulative declines in SRH. Only in the oldest old (85+), the impact of a single disease was similar to that of co-occurring diseases. Results were similar for men and women.
  
  
  CONCLUSIONS
  Our findings help to improve understanding of the impact multimorbidity has on SRH: Having a single disease increases the chance of poor health more than each co-occurring disease, indicating some overlap between diseases or adaptation to declining health.
authors: Department of Epidemiology and Biostatistics, EMGO/Longitudinal Aging Study Amsterdam, VU University Medical Centre, Van der Boechorststraat 7, 1081 BT Amsterdam, The Netherlands. h.galenkamp@vumc.nl
authors: Henrike
authors: H
authors: Galenkamp
authors: Arjan W
authors: AW
authors: Braam
authors: Martijn
authors: M
authors: Huisman
authors: Dorly J H
authors: DJ
authors: Deeg
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D001294:Attitude to Health; D002908:Chronic Disease; D015897:Comorbidity; D005260:Female; D006801:Humans; D008137:Longitudinal Studies; D008297:Male; D008875:Middle Aged; D009426:Netherlands; D012647:Self-Assessment; D012959:Socioeconomic Factors