title: The Dynamic contribution of chronic conditions to temporal trends in disability among U.S. adults.
abstract: BACKGROUND
  Although evidence has shown that U.S. late-life disability has been declining, studies have also suggested that there has been an increase in chronic diseases between 1984 and 2007.
  
  
  OBJECTIVE
  To further illuminate these potentially contradictory trends, we explicate how the contribution of chronic conditions changes across four common types of disability (ADL, IADL, mobility disability, and functional limitations) by age (A), period (P), and birth cohorts (C) among adults aged 20 and above.
  
  
  METHODS
  Our data came from seven cross-sectional waves of the National Health and Nutrition Examination Survey (NHANES). We utilize a cross-classified random effect model (CCREM) to simultaneously estimate age, period, and cohort trends for each disability. Each chronic condition was sequentially then simultaneously added to our base models (sociodemographics only). Reductions in predicted probability from the base model were then calculated for each chronic condition by each temporal dimension (A/P/C) to assess the contribution of each chronic condition.
  
  
  RESULTS
  There was increasing age-based contribution of chronic conditions to all disabilities. The period-based contribution remained quite stagnant across years while cohort-based contributions showed a continual decline for recent cohorts. Arthritis showed the greatest contribution to disability of all types which was followed by obesity. Cancer was the least important contributor to disabilities.
  
  
  CONCLUSIONS
  Although chronic conditions are becoming less disabling across recent cohorts, other competing risk factors might suggest prevailing causes of disability.
authors.affiliation: Institute for Behavioral and Community Health, San Diego State University, 9245 Sky Park Court, Suite 220, San Diego, CA 92123, USA; Graduate School of Public Health, San Diego State University, 5500 Campanile Dr. Hardy Tower, Room 119, San Diego, CA 92182-4162, USA. Electronic address: slin@mail.sdsu.edu.
authors.forename: Shih-Fan
authors.initials: SF
authors.lastname: Lin
authors.affiliation: Department of Sociology, San Diego State University, 5500 Campanile Dr. Nasatir Hall, Room 224, San Diego, CA 92123, USA.
authors.forename: Audrey N
authors.initials: AN
authors.lastname: Beck
authors.affiliation: Graduate School of Public Health, San Diego State University, 5500 Campanile Dr. Hardy Tower, Room 119, San Diego, CA 92182-4162, USA; Center for Economic and Social Research USC, Population Research Center, 635 Downey Way, Los Angeles, CA 90089-3332, USA.
authors.forename: Brian K
authors.initials: BK
authors.lastname: Finch
mesh_terms: D000203:Activities of Daily Living; D000328:Adult; D000367:Age Factors; D000368:Aged; D000375:Aging; D001168:Arthritis / Q000150:complications*; D002908:Chronic Disease; D015897:Comorbidity; D003430:Cross-Sectional Studies; D006233:Persons with Disabilities; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D051346:Mobility Limitation; D009749:Nutrition Surveys; D009765:Obesity / Q000150:complications*; D012307:Risk Factors; D014481:United States; D055815:Young Adult
keywords: Age-period-cohort; Chronic condition; Disability