title: Trends in U.S. adult chronic disability rates over time.
abstract: BACKGROUND
  Trends in the patterns and prevalence of chronic disability among U.S. residents carry important implications for public health and public policies across multiple societal sectors.
  
  
  OBJECTIVE
  To examine trends in U.S. adult population rates of chronic disability from 1998 to 2011 using 7 different disability measures and examining the implications of trends in population age, race and ethnicity, and body mass index (BMI).
  
  
  METHODS
  We used National Health Interview Survey data on civilian, non-institutionalized U.S. residents ages ≥ 18 from selected years between 1998 and 2011. We used self-reported information on functional impairments, activity/participation limitations, and expected duration to create 7 chronic disability measures. We used direct standardization to account for changes in age, race/ethnicity, and BMI distributions over time. Multivariable logistic regression models identified associations of disability with sociodemographic characteristics.
  
  
  RESULTS
  Without adjustment, population rates of all 7 disabilities increased significantly (p < 0.0001) from 1998 to 2011. The absolute percentage change was greatest for movement difficulties: 19.3% in 1998 and 23.3% in 2011. After separate adjustments for trends in age, race/ethnicity, and BMI distributions, 6 disability types continued to show increased rates over time (p < 0.01), except for sensory disabilities. Over time, poor education, poverty, and unemployment remained significantly associated with disability.
  
  
  CONCLUSIONS
  If these trends continue, the numbers and proportions of U.S. residents with various disabilities will continue rising in coming years. In particular, the prevalence of movement difficulties and work limitations will increase. Furthermore, disability will remain strongly associated with low levels of education, employment, and income.
authors.affiliation: Mongan Institute for Health Policy, Massachusetts General Hospital, Boston, USA; Department of Medicine, Harvard Medical School, Boston, USA. Electronic address: liezzoni@mgh.harvard.edu.
authors.forename: Lisa I
authors.initials: LI
authors.lastname: Iezzoni
authors.affiliation: Department of Quantitative Health Sciences, University of Massachusetts Medical School, Worcester, MA, USA.
authors.forename: Stephen G
authors.initials: SG
authors.lastname: Kurtz
authors.affiliation: Department of Quantitative Health Sciences, University of Massachusetts Medical School, Worcester, MA, USA; Center for Healthcare Organization and Implementation Research (CHOIR), Bedford Veteran Affairs Medical Center, Bedford, MA, USA.
authors.forename: Sowmya R
authors.initials: SR
authors.lastname: Rao
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D015992:Body Mass Index; D006233:Persons with Disabilities; D005260:Female; D006304:Health Status; D006306:Health Surveys; D006801:Humans; D008297:Male; D008875:Middle Aged; D009068:Movement; D012959:Socioeconomic Factors; D014478:Unemployment; D014481:United States; D055815:Young Adult
keywords: Disability; Movement difficulties; National health interview survey; Prevalence rates