title: An epidemiological study of urban and rural children in Pakistan: examining the relationship between delayed psychomotor development, low birth weight and postnatal growth failure.
abstract: BACKGROUND
  Low birth weight is known to be associated with postnatal growth failure. It is not yet established that both conditions are determinants of psychomotor development. The study investigated whether or not low birth weight leads to delayed psychomotor development of a child, and whether it can be mitigated by adequate postnatal growth.
  
  
  METHODS
  A cross-sectional study was conducted in 2002 in 15 rural and 11 urban communities of Sindh province, Pakistan. Assessment of 1234 children less than 3 years of age included Bayley's Scale of Infant Development II, socioeconomic questionnaire and anthropometry; WHO standards were used to calculate z-scores of height-for-age, weight-for-height and weight-for-age. The underlying study hypotheses were tested through multiple regression modelling.
  
  
  RESULTS
  Out of 1219 children, 283 (23.2%) had delayed psychomotor development and 639 (52.4%) were undernourished according to the composite index of anthropometric failure. Strong negative associations with the psychomotor development index were detected between stunting and being underweight, with a larger magnitude of effect for stunting (p<0.001). The strong relationship persisted even when the analysis was restricted to non-malnourished children. The psychomotor index increased by 2.07 points with every unit increase in height-for-age z-score.
  
  
  CONCLUSIONS
  The relationship between low birth weight and psychomotor development appears to be mediated largely by postnatal growth and nutritional status. This association suggests that among undernourished children there is significant likelihood of a group that is developmentally delayed. It is important to emphasize developmental needs in programmes that target underprivileged children.
authors.affiliation: Informed Decisions for Actions in Maternal and Newborn Health (IDEAS), Department of Disease Control, Faculty of Infectious and Tropical Diseases, London School of Hygiene & Tropical Medicine, Keppel St, London WC1E 7HT, UK bilal.avan@lshtm.ac.uk.
authors.forename: Bilal I
authors.initials: BI
authors.lastname: Avan
authors.affiliation: Department of Social and Preventive Medicine, University of Montreal, 850 St-Denis, Montreal H2X 0A9, Quebec, Canada.
authors.forename: Syed A
authors.initials: SA
authors.lastname: Raza
authors.affiliation: Nutrition and Public Health Intervention Research Unit, Department of Population Health, Faculty of Epidemiology and Population Health, London School of Hygiene & Tropical Medicine, Keppel St, London WC1E 7HT, UK.
authors.forename: Betty R
authors.initials: BR
authors.lastname: Kirkwood
mesh_terms: D000886:Anthropometry; D001827:Body Height; D001835:Body Weight; D002648:Child; D015362:Child Nutrition Disorders / Q000150:complications; D003430:Cross-Sectional Studies; D016021:Epidemiologic Studies; D005183:Failure to Thrive / Q000453:epidemiology*; D006801:Humans; D007223:Infant; D007230:Infant, Low Birth Weight; D007231:Infant, Newborn; D009752:Nutritional Status; D010154:Pakistan / Q000453:epidemiology; D011596:Psychomotor Disorders / Q000453:epidemiology*; D012424:Rural Population / Q000706:statistics & numerical data*; D012959:Socioeconomic Factors; D014505:Urban Population / Q000706:statistics & numerical data*
keywords: Child development; Low birth weight; Nutritional status; Postnatal growth failure; Psychomotor development