title: Racial variation in retinopathy of prematurity. The Cryotherapy for Retinopathy of Prematurity Cooperative Group.
abstract: OBJECTIVE
  To determine and compare the incidence of severe, vision-threatening retinopathy of prematurity (ROP) in black and white low-birth-weight infants.
  
  
  METHODS
  Prospective cohort study.
  
  
  METHODS
  Seventy neonatal intensive care units in 23 US participating centers in the Multicenter Trial of Cryotherapy for Retinopathy of Prematurity.
  
  
  METHODS
  A total of 4099 premature infants weighing less than 1251 g at birth were enrolled to evaluate the natural history of ROP. This 'Natural History' cohort included 2158 white infants and 1584 black infants who were followed up prospectively according to a Natural History protocol.
  
  
  METHODS
  Incidence and severity of acute ROP.
  
  
  RESULTS
  While ROP occurred with similar frequency in all racial subgroups, severe ROP was less common in black infants. One hundred sixty (7.4%) of 2158 white infants reached threshold ROP (defined as at least 5 contiguous or 8 cumulative clock-hours of stage 3 retinopathy in zone 1 or zone 2 in the presence of "plus disease" [dilation and tortuosity of the posterior pole blood vessels]), but only 51 (3.2%) of 1584 black infants progressed to threshold ROP. Using multiple logistic regression analysis, race emerged as a highly significant factor (P < .001) in the development of threshold disease, even when birth weight, gestational age status at delivery, sex, multiple births, and transport status were considered.
  
  
  CONCLUSIONS
  Severe, vision-threatening ROP occurs with greater frequency in low-birth-weight white infants than in low-birth-weight black infants who are seemingly at equivalent risk. The reason for this disparity is unknown. We speculate that differences in retinal pigmentation may confer relative protection against free radical-mediated phototoxic injury in black infants.
authors.affiliation: N. Edgar Miles Center for Pediatric Ophthalmology, Department of Ophthalmology, Medical University of South Carolina, Charleston, USA. saundric@musc.edu
authors.forename: R A
authors.initials: RA
authors.lastname: Saunders
authors.forename: M L
authors.initials: ML
authors.lastname: Donahue
authors.forename: L M
authors.initials: LM
authors.lastname: Christmann
authors.forename: A V
authors.initials: AV
authors.lastname: Pakalnis
authors.forename: B
authors.initials: B
authors.lastname: Tung
authors.forename: R J
authors.initials: RJ
authors.lastname: Hardy
authors.forename: D L
authors.initials: DL
authors.lastname: Phelps
mesh_terms: D001724:Birth Weight; D044383:Black People; D015331:Cohort Studies; D003452:Cryosurgery; D005260:Female; D005865:Gestational Age; D006801:Humans; D015994:Incidence; D007223:Infant; D007231:Infant, Newborn; D008297:Male; D011446:Prospective Studies; D012178:Retinopathy of Prematurity / Q000208:ethnology* / Q000209:etiology / Q000601:surgery; D012720:Severity of Illness Index; D014481:United States / Q000453:epidemiology; D044465:White People; D001741:Black or African American