title: Does household access to improved water and sanitation in infancy and childhood predict better vocabulary test performance in Ethiopian, Indian, Peruvian and Vietnamese cohort studies?
abstract: Test associations between household water and sanitation (W&S) and children's concurrent and subsequent Peabody Picture Vocabulary Test (PPVT) scores.
  
  
  
  Prospective cohort study.
  
  
  
  Ethiopia, India, Peru, Vietnam.
  
  
  
  7269 children.
  
  
  
  PPVT scores at 5 and 8 years. Key exposure variables were related to W&S, and collected at 1, 5 and 8 years, including 'improved' water (eg, piped, public tap or standpipe) and 'improved' toilets (eg, collection, storage, treatment and recycling of human excreta).
  
  
  
  Access to improved water at 1 year was associated with higher language scores at 5 years (3/4 unadjusted associations) and 8 years (4/4 unadjusted associations). Ethiopian children with access to improved water at 1 year had test scores that were 0.26 SD (95% CI 0.17 to 0.36) higher at 5 years than children without access. Access to improved water at 5 years was associated with higher concurrent PPVT scores (in 3/4 unadjusted associations), but not later scores (in 1/4 unadjusted associations). 5-year-old Peruvian children with access to improved water had better concurrent performance on the PPVT (0.44 SD, 95% CI 0.30 to 0.59) than children without access to improved water. Toilet access at 1 year was also associated with better PPVT scores at 5 years (3/4 unadjusted associations) and sometimes associated with test results at 8 years (2/4 unadjusted associations). Toilet access at 5 years was associated with concurrent PPVT scores (3/4 unadjusted associations). More than half of all associations in unadjusted models (water and toilets) persisted in adjusted models, particularly for toilets in India, Peru and Vietnam.
  
  
  
  Access to 'improved' water and toilets had independent associations with children's PPVT scores that often persisted with adjustment for covariates. Our findings suggest that effects of W&S may go beyond subacute and acute infections and physical growth to include children's language performance, a critical component of cognitive development.
authors.affiliation: Research and Quality Assurance; IMA World Health/Tanzania, Dar es Salaam, Tanzania.
authors.forename: Kirk A
authors.initials: KA
authors.lastname: Dearden
authors.affiliation: Department of Global Health, Boston University, Boston, Massachusetts, USA.|Health Economics and Epidemiology Research Office, Faculty of Health Sciences, Department of Internal Medicine, School of Clinical Medicine, University of the Witwatersrand, Johannesburg, South Africa.|Department of Epidemiology, Boston University, School of Public Health, Boston, Massachusetts, USA.
authors.forename: Alana T
authors.initials: AT
authors.lastname: Brennan
authors.affiliation: Economics and Sociology Departments and Population Studies Center, University of Pennsylvania, Philadelphia, Pennsylvania, USA.
authors.forename: Jere R
authors.initials: JR
authors.lastname: Behrman
authors.affiliation: Population Studies Center, University of Pennsylvania, Philadelphia, Pennsylvania, USA.
authors.forename: Whitney
authors.initials: W
authors.lastname: Schott
authors.affiliation: Department of Health Science, Brigham Young University, Salt Lake City, Utah, USA.
authors.forename: Benjamin T
authors.initials: BT
authors.lastname: Crookston
authors.affiliation: School of Public Health, Yale University, New Haven, Connecticut, USA.
authors.forename: Debbie L
authors.initials: DL
authors.lastname: Humphries
authors.affiliation: Instituto de Investigación Nutricional, Lima, Peru.
authors.forename: Mary E
authors.initials: ME
authors.lastname: Penny
authors.affiliation: Division of Community Health Sciences, School of Public Health, University of California at Berkeley, Berkeley, California, USA.
authors.forename: Lia C H
authors.initials: LC
authors.lastname: Fernald
mesh_terms: D002648:Child; D002657:Child Development; D002675:Child, Preschool; D015331:Cohort Studies; D005002:Ethiopia; D005260:Female; D006801:Humans; D007194:India; D007223:Infant; D007807:Language Tests / Q000706:statistics & numerical data*; D008297:Male; D010568:Peru; D011446:Prospective Studies; D012499:Sanitation / Q000706:statistics & numerical data*; D014744:Vietnam; D014825:Vocabulary; D060753:Water Quality
keywords: PPVT; child development; cognition; lower and middle income countries; sanitation; water