title: Contribution of chronic diseases to disability in elderly people in countries with low and middle incomes: a 10/66 Dementia Research Group population-based survey.
abstract: BACKGROUND
  Disability in elderly people in countries with low and middle incomes is little studied; according to Global Burden of Disease estimates, visual impairment is the leading contributor to years lived with disability in this population. We aimed to assess the contribution of physical, mental, and cognitive chronic diseases to disability, and the extent to which sociodemographic and health characteristics account for geographical variation in disability.
  
  
  METHODS
  We undertook cross-sectional surveys of residents aged older than 65 years (n=15 022) in 11 sites in seven countries with low and middle incomes (China, India, Cuba, Dominican Republic, Venezuela, Mexico, and Peru). Disability was assessed with the 12-item WHO disability assessment schedule 2.0. Dementia, depression, hypertension, and chronic obstructive pulmonary disease were ascertained by clinical assessment; diabetes, stroke, and heart disease by self-reported diagnosis; and sensory, gastrointestinal, skin, limb, and arthritic disorders by self-reported impairment. Independent contributions to disability scores were assessed by zero-inflated negative binomial regression and Poisson regression to generate population-attributable prevalence fractions (PAPF).
  
  
  RESULTS
  In regions other than rural India and Venezuela, dementia made the largest contribution to disability (median PAPF 25.1% [IQR 19.2-43.6]). Other substantial contributors were stroke (11.4% [1.8-21.4]), limb impairment (10.5% [5.7-33.8]), arthritis (9.9% [3.2-34.8]), depression (8.3% [0.5-23.0]), eyesight problems (6.8% [1.7-17.6]), and gastrointestinal impairments (6.5% [0.3-23.1]). Associations with chronic diseases accounted for around two-thirds of prevalent disability. When zero inflation was taken into account, between-site differences in disability scores were largely attributable to compositional differences in health and sociodemographic characteristics.
  
  
  CONCLUSIONS
  On the basis of empirical research, dementia, not blindness, is overwhelmingly the most important independent contributor to disability for elderly people in countries with low and middle incomes. Chronic diseases of the brain and mind deserve increased prioritisation. Besides disability, they lead to dependency and present stressful, complex, long-term challenges to carers. Societal costs are enormous.
  
  
  BACKGROUND
  Wellcome Trust; WHO; US Alzheimer's Association; Fondo Nacional de Ciencia Y Tecnologia, Consejo de Desarrollo Cientifico Y Humanistico, Universidad Central de Venezuela.
authors: King's College London, Institute of Psychiatry, Health Services and Population Research Department, Centre for Public Mental Health, London, UK. r.sousa@iop.kcl.ac.uk
authors: Renata M
authors: RM
authors: Sousa
authors: Cleusa P
authors: CP
authors: Ferri
authors: Daisy
authors: D
authors: Acosta
authors: Emiliano
authors: E
authors: Albanese
authors: Mariella
authors: M
authors: Guerra
authors: Yueqin
authors: Y
authors: Huang
authors: K S
authors: KS
authors: Jacob
authors: A T
authors: AT
authors: Jotheeswaran
authors: Juan J Llibre
authors: JJ
authors: Rodriguez
authors: Guillermina Rodriguez
authors: GR
authors: Pichardo
authors: Marina Calvo
authors: MC
authors: Rodriguez
authors: Aquiles
authors: A
authors: Salas
authors: Ana Luisa
authors: AL
authors: Sosa
authors: Joseph
authors: J
authors: Williams
authors: Tirso
authors: T
authors: Zuniga
authors: Martin
authors: M
authors: Prince
mesh_terms: D000367:Age Factors; D000368:Aged; D002681:China / Q000453:epidemiology; D002908:Chronic Disease / Q000453:epidemiology*; D003430:Cross-Sectional Studies; D003704:Dementia / Q000150:complications / Q000191:economics / Q000453:epidemiology*; D006233:Persons with Disabilities / Q000706:statistics & numerical data*; D004293:Dominican Republic / Q000453:epidemiology; D006306:Health Surveys; D006801:Humans; D007194:India / Q000453:epidemiology; D008800:Mexico / Q000453:epidemiology; D010568:Peru / Q000453:epidemiology; D011203:Poverty / Q000706:statistics & numerical data; D012044:Regression Analysis; D012959:Socioeconomic Factors; D014687:Venezuela / Q000453:epidemiology