title: Reduced utility of serum IGF-1 levels in predicting retinopathy of prematurity reflects maternal ethnicity.
abstract: OBJECTIVE
  To validate known risk factors and identify a threshold level for serum insulin-like growth factor 1 (IGF-1) in the development of severe retinopathy of prematurity (ROP) in an ethnically diverse population at a tertiary neonatal unit, 2011-2013.
  
  
  METHODS
  A prospective cohort masked study was conducted. Serum IGF-1 levels at 31, 32 and 33 weeks were measured and risk factor data collected including gestational age (GA), birth weight (BW), absolute weight gain (AWG) and maternal ethnicity. The eventual ROP outcome was divided into two groups: minimal ROP (Stages 0 and 1) and severe ROP (Stage 2 or worse including Type 1 ROP).
  
  
  RESULTS
  36 patients were recruited: 14 had minimal ROP and 22 severe ROP. Significant differences between the groups were found in GA, BW, AWG and IGF-1 at 32 and 33 weeks. There was minimal rise in IGF-1 in Stage 2 patients and/or black patients (p=0.0013) between 32 and 33 weeks but no pragmatic threshold level of IGF-1 that could distinguish between minimal or severe ROP.
  
  
  CONCLUSIONS
  There were significant differences in GA, BW, AWG and IGF-1 at 32 and 33 weeks between those babies with severe ROP and those with minimal ROP. However, there was no threshold level of IGF-1 at a time point between 31 and 33 weeks that can be used to exclude a large proportion of babies from screening. We also found ethnic differences in IGF-1 levels with infants born to black mothers having significantly lower IGF-1 levels at 32 and 33 weeks gestation. The determination of ROP risk using IGF-1 is a race-specific phenomenon.
authors: The Royal London Hospital, Barts Health NHS Trust, London, UK Moorfields Eye Hospital NHS Foundation Trust, London, UK.
authors: M Ashwin
authors: MA
authors: Reddy
authors: The Royal London Hospital, Barts Health NHS Trust, London, UK Moorfields Eye Hospital NHS Foundation Trust, London, UK.
authors: Himanshu I
authors: HI
authors: Patel
authors: The Royal London Hospital, Barts Health NHS Trust, London, UK.
authors: Shah M
authors: SM
authors: Karim
authors: The Royal London Hospital, Barts Health NHS Trust, London, UK.
authors: Helen
authors: H
authors: Lock
authors: Department of Clinical Biochemistry, Croydon University Hospital, London, UK.
authors: Leslie
authors: L
authors: Perry
authors: Moorfields Eye Hospital NHS Foundation Trust, London, UK.
authors: Catey
authors: C
authors: Bunce
authors: The Royal London Hospital, Barts Health NHS Trust, London, UK Blizard Institute, Barts and the London School of Medicine and Dentistry, London, UK.
authors: Steve
authors: S
authors: Kempley
authors: The Royal London Hospital, Barts Health NHS Trust, London, UK Blizard Institute, Barts and the London School of Medicine and Dentistry, London, UK.
authors: Ajay K
authors: AK
authors: Sinha
mesh_terms: D044466:Asian People / Q000208:ethnology; D001724:Birth Weight; D044383:Black People / Q000208:ethnology; D015331:Cohort Studies; D005006:Ethnicity; D005260:Female; D005865:Gestational Age; D006801:Humans; D007124:Immunoenzyme Techniques; D007334:Insulin-Like Growth Factor I / Q000378:metabolism*; D007363:Intensive Care Units, Neonatal; D009035:Mothers; D011446:Prospective Studies; D012178:Retinopathy of Prematurity / Q000097:blood* / Q000208:ethnology*; D012307:Risk Factors; D015430:Weight Gain; D044465:White People / Q000208:ethnology
chemical_list: D007334:Insulin-Like Growth Factor I
keywords: Biochemistry; Child health (paediatrics); Retina; Treatment Lasers