title: Body mass index, dementia, and mortality in the elderly.
abstract: OBJECTIVE
  To explore the association between body mass index and mortality in the elderly taking the diagnosis of dementia into account.
  
  
  METHODS
  Cohort study.
  
  
  METHODS
  cohort study of aging in Medicare recipients in New York City.
  
  
  METHODS
  1,452 elderly individuals 65 years and older of both genders.
  
  
  METHODS
  We used proportional hazards regression for longitudinal multivariate analyses relating body mass index (BMI) and weight change to all-cause mortality.
  
  
  RESULTS
  There were 479 deaths during 9,974 person-years of follow-up. There were 210 cases of prevalent dementia at baseline, and 209 cases of incident dementia during follow-up. Among 1,372 persons with BMI information, the lowest quartile of BMI was associated with a higher mortality risk compared to the second quartile (HR=1.5; 95% CI: 1.1,2.0) after adjustment for age, gender, education, ethnic group, smoking, cancer, and dementia. When persons with dementia were excluded, both the lowest (HR=1.9; 95% CI=.3,2.6) and highest (HR=1.6; 95% CI: 1.1,2.3) quartiles of BMI were related to higher mortality. Weight loss was related to a higher mortality risk (HR=1.5; 95% CI: 1.2,1.9) but this association was attenuated when persons with short follow-up or persons with dementia were excluded.
  
  
  CONCLUSIONS
  The presence of dementia does not explain the association between low BMI and higher mortality in the elderly. However, dementia may explain the association between weight loss and higher mortality.
authors.affiliation: Taub Institute for Research in Alzheimer's Disease and the Aging Brain, Columbia University, New York, NY 10032, USA. jal94@columbia.edu
authors.forename: J A
authors.initials: JA
authors.lastname: Luchsinger
authors.forename: B
authors.initials: B
authors.lastname: Patel
authors.forename: M X
authors.initials: MX
authors.lastname: Tang
authors.forename: N
authors.initials: N
authors.lastname: Schupf
authors.forename: R
authors.initials: R
authors.lastname: Mayeux
mesh_terms: D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D000375:Aging / Q000502:physiology* / Q000523:psychology; D015992:Body Mass Index; D002423:Cause of Death; D015331:Cohort Studies; D003704:Dementia / Q000150:complications / Q000175:diagnosis / Q000453:epidemiology*; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D015994:Incidence; D008137:Longitudinal Studies; D008297:Male; D009026:Mortality; D015999:Multivariate Analysis; D009765:Obesity / Q000150:complications / Q000453:epidemiology; D018570:Risk Assessment; D012307:Risk Factors; D012737:Sex Factors; D015431:Weight Loss / Q000502:physiology*