title: An estimation of the prevalence of intellectual disabilities and its association with age in rural and urban populations in India.
abstract: BACKGROUND
  Intellectual disability (ID) is a global public health concern. Prevalence of ID and its association with age and other demographic factors is required for planning purposes in India.
  
  
  OBJECTIVE
  This study analyzed the age-adjusted prevalence of ID in rural and urban populations and its correlation with age in children and adults.
  
  
  METHODS
  Disability data published in the report (2002) of National Sample Survey Organization were analyzed, using Z-test to measure differences in age-adjusted prevalence. Spearman rho was calculated to determine strength and direction of the association, and regression analysis was used to predict prevalence rate, based on age in rural and urban population settings.
  
  
  RESULTS
  Overall, India has a prevalence of 10.5/1000 in ID. Urban population has slightly higher rate (11/1000) than rural (10.08/1000; P = 0.044). Age was found to be highly correlated with prevalence of ID in rural children (ϱ =0.981, P = 0.019) as well as in children (ϱ = -0.954, P = 0.000) and adults (ϱ = -0.957, P = 0.000) in urban population. The possibility of confounding or the existence of covariates for children in urban settings was noted.
  
  
  CONCLUSIONS
  Results of this study match findings in other epidemiological studies. However, multistage, large-scale studies are recommended for investigating prevalence rates with different severity levels of ID.
authors.affiliation: Department of Epidemiology, School of Health Sciences, College of Public Service, Jackson State University, Jackson, USA.
authors.forename: Ram
authors.initials: R
authors.lastname: Lakhan
authors.affiliation: Department of Public Health, Eastern Washington University, Cheney, Washington, USA.
authors.forename: Olúgbémiga T
authors.initials: OT
authors.lastname: Ekúndayò
authors.affiliation: Department of Behavioral Health and Education, School of Health Sciences, College of Public Service, Jackson State University, Jackson, Mississippi, USA.
authors.forename: Mohammad
authors.initials: M
authors.lastname: Shahbazi
keywords: Age; India; National Sample Survey Organization report; confounding; covariates; intellectual disability; population studies; prevalence; rural; urban