title: Preterm birth and later retinal detachment: a population-based cohort study of more than 3 million children and young adults.
abstract: OBJECTIVE
  Ophthalmologic complications after preterm birth are common. Small studies show an association between retinopathy of prematurity and later retinal detachment. There are no population-based studies of preterm birth and risk of retinal detachment, which was the objective of the current investigation.
  
  
  METHODS
  Nationwide Swedish cohort study based on population registries.
  
  
  METHODS
  Of 3 423 697 subjects born in Sweden, 1 271 725 were born between 1973 and 1986 (i.e., before the national screening program for retinopathy of prematurity started), and 2 151 972 were born between 1987 and 2008. The participants were followed up from 1 year of age until 2009.
  
  
  METHODS
  Unadjusted and adjusted hazard ratios (HRs) for retinal detachment were calculated using Cox proportional hazards regression.
  
  
  METHODS
  Incident retinal detachment, as defined by a diagnosis in the Swedish Patient Register (both inpatient and hospital-based outpatient data).
  
  
  RESULTS
  During follow-up (median follow-up, 17.4 years), 1749 subjects were diagnosed with retinal detachment. Among the 188 852 subjects born prematurely (i.e., at <37 weeks of gestation), there were 124 cases of retinal detachment, of which 42 occurred in the 20 470 subjects born before 32 weeks of gestation. Compared with subjects born at term (37-41 weeks), the adjusted HR for retinal detachment after extremely preterm birth (<28 weeks of gestation) was 19.2 (95% confidence interval [CI], 10.3-35.8) for births between 1973 and 1986 and 8.95 (95% CI, 3.98-20.1) for births between 1987 and 2008. The corresponding HRs in subjects born very prematurely (28-31 weeks) were 4.32 (95% CI, 2.70-6.90) and 2.80 (95% CI, 1.38-5.69), respectively. Moderately preterm birth (32-36 weeks) was not associated with an increased risk of retinal detachment.
  
  
  CONCLUSIONS
  Birth before 32 weeks of gestation is associated with a substantially increased relative risk of retinal detachment. These findings may have implications for ophthalmologic follow-up of children and adults born very prematurely.
authors.affiliation: Clinical Epidemiology Unit, Department of Medicine Solna, Karolinska Institutet, Stockholm, Sweden; Department of Women's and Children's Health, Karolinska Institutet, Stockholm, Sweden. Electronic address: anna-karin.edstedt.bonamy@ki.se.
authors.forename: Anna-Karin E
authors.initials: AK
authors.lastname: Bonamy
authors.forename: Gerd
authors.initials: G
authors.lastname: Holmström
authors.forename: Olof
authors.initials: O
authors.lastname: Stephansson
authors.forename: Jonas F
authors.initials: JF
authors.lastname: Ludvigsson
authors.forename: Sven
authors.initials: S
authors.lastname: Cnattingius
mesh_terms: D000293:Adolescent; D000328:Adult; D001724:Birth Weight; D002648:Child; D015331:Cohort Studies; D005260:Female; D005865:Gestational Age; D006801:Humans; D015994:Incidence; D052577:Infant, Extremely Low Birth Weight; D019102:Infant, Very Low Birth Weight; D008297:Male; D047928:Premature Birth / Q000453:epidemiology*; D016016:Proportional Hazards Models; D012042:Registries; D012163:Retinal Detachment / Q000175:diagnosis / Q000453:epidemiology*; D012307:Risk Factors; D013548:Sweden / Q000453:epidemiology; D055815:Young Adult