title: Age, body mass index, and functional illness.
abstract: OBJECTIVE
  This study examines the relationship between body mass index (BMI) and selected measures of functional illness and whether the relationship between BMI and these outcomes is stronger in advanced ages.
  
  
  METHODS
  Four measures of functional illness were examined in national, longitudinal survey of noninstitutionalized adults. Tobit and Poisson models were used to estimate cross-sectional and longitudinal specifications.
  
  
  RESULTS
  BMI was related to functional illness but not in a linear form: Both obese and underweight persons manifested higher levels of functional illness on most outcomes during the baseline survey. Results from the change analyses, however, revealed that obesity was associated with more days hospitalized or ill in bed and an increase in functional limitations.
  
  
  CONCLUSIONS
  Obesity is associated with functional illness, but there is no evidence from these data that this relationship is stronger for older adults. Rather, the effect of obesity on some measures of functional illness is greater in the younger and middle ages.
authors.affiliation: Department of Sociology, Purdue University, West Lafayette, Indiana, USA. ferraro@purdue.edu
authors.forename: K F
authors.initials: KF
authors.lastname: Ferraro
authors.forename: T L
authors.initials: TL
authors.lastname: Booth
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000375:Aging / Q000502:physiology*; D015992:Body Mass Index; D003430:Cross-Sectional Studies; D005260:Female; D006304:Health Status; D006801:Humans; D008137:Longitudinal Studies; D008297:Male; D008875:Middle Aged; D009765:Obesity / Q000150:complications; D011795:Surveys and Questionnaires