title: Interpretation of World Health Organization growth charts for assessing infant malnutrition: a randomised controlled trial.
abstract: OBJECTIVE
  The study aims to assess the effects of switching from National Center for Health Statistics (NCHS) growth references to World Health Organization (WHO) growth standards on health-care workers' decisions about malnutrition in infants aged <6 months.
  
  
  METHODS
  We conducted a single blind randomised crossover trial involving 78 health-care workers (doctors, clinical officers, health service assistants) in Southern Malawi. Participants were offered hypothetical clinical scenarios with the same infant plotted on NCHS-based weight-for-age charts and again on WHO-based charts. Additional scenarios compared growth charts with a single final weight against charts with the same final weight plus a preceding growth trend. Reported (i) level of concern, (ii) referral suggestions and (iii) feeding advice were elicited with a questionnaire.
  
  
  RESULTS
  Even after adjusting for health-care worker type and experience, using WHO rather than NCHS charts increased: (i) concern: aOR 4.4 (95% CI 2.4-8.1); (ii) odds of referral: aOR 5.1 (95% CI 2.4-10.8); and (iii) odds of feeding advice which would interrupt exclusive breastfeeding (aOR 2.4, 95% CI 1.2-4.9). A preceding steady growth trend line did not affect concern, referral or feeding advice.
  
  
  CONCLUSIONS
  Health-care workers take insufficient account of linear growth trend, clinical and feeding status when interpreting a low weight-for-age plot. Because more infants <6 months fall below low centile lines on WHO growth charts, their use may increase inappropriate referrals and risks undermining already low rates of exclusive breastfeeding. To avoid their being misinterpreted in this way, WHO charts need accompanying guidelines and training materials that recognise and address this possible adverse effect.
authors.affiliation: UCL Institute for Global Health, University College London, London, United Kingdom.
authors.forename: Umar N
authors.initials: UN
authors.lastname: Ahmad
authors.forename: Mwawi
authors.initials: M
authors.lastname: Yiwombe
authors.forename: Patrick
authors.initials: P
authors.lastname: Chisepo
authors.forename: Tim J
authors.initials: TJ
authors.lastname: Cole
authors.forename: Geert T
authors.initials: GT
authors.lastname: Heikens
authors.forename: Marko
authors.initials: M
authors.lastname: Kerac
mesh_terms: D001942:Breast Feeding; D018592:Cross-Over Studies; D057238:Growth Charts; D006282:Health Personnel; D006801:Humans; D007223:Infant; D007228:Infant Nutrition Disorders / Q000175:diagnosis*; D007227:Infant Nutritional Physiological Phenomena; D008295:Malawi; D009752:Nutritional Status; D016037:Single-Blind Method; D018709:Statistics, Nonparametric; D014944:World Health Organization
keywords: breastfeeding; growth chart; international child health; nutrition infant; randomised controlled trial