title: Familial correlation of retinal vascular caliber in Singapore Chinese.
abstract: OBJECTIVE
  Our study aimed to explore the heritability of retinal vascular caliber among Singapore Chinese families.
  
  
  METHODS
  In the Strabismus, Amblyopia, and Refractive Error Study in Singaporean Chinese Preschoolers (STARS) family study conducted from 2008 to 2010, a total of 727 participants (304 parent-child pairs, 83 sibling pairs, and 87 spouse pairs) were included in the analysis. According to standardized protocols, retinal photography, blood pressure measurements, anthropometric measurements, and interviews were performed at clinic. Retinal vascular caliber was assessed by a computer-assisted imaging program (IVAN). Familial correlation of retinal vascular caliber among family pairs was calculated by the FCOR procedure with S.A.G.E. computer software program package and heritability was double the value of the familial correlation.
  
  
  RESULTS
  Mean age was 8.59 years in 304 children and 39.90 years in 423 parents. Mean CRAE and CRVE were 157.09 and 220.80 μm in children, and 150.29 and 220.70 μm in parents, respectively. In multivariate analysis, familial correlation of CRVE was 0.36 (P < 0.001) among parent-child pairs and 0.28 (P < 0.05) among sibling pairs, respectively. Heritability of CRVE was 0.72 and 0.56 among parent-child pairs and sibling pairs, respectively. Family correlation and heritability of CRAE were not significant.
  
  
  CONCLUSIONS
  This familial correlation study showed a strong correlation of retinal venular caliber in Singapore Chinese families among parent-child pairs and sibling pairs, independent of age, sex, blood pressure, and BMI. Our findings provide further evidence on substantial heritability of the microvasculature.
authors.affiliation: Singapore Eye Research Institute, Singapore National Eye Centre, Singapore.
authors.forename: Ling-Jun
authors.initials: LJ
authors.lastname: Li
authors.forename: Jiemin
authors.initials: J
authors.lastname: Liao
authors.forename: Qiao
authors.initials: Q
authors.lastname: Fan
authors.forename: Carol Yim-Lui
authors.initials: CY
authors.lastname: Cheung
authors.forename: M Kamran
authors.initials: MK
authors.lastname: Ikram
authors.forename: Ching-Yu
authors.initials: CY
authors.lastname: Cheng
authors.forename: Seang-Mei
authors.initials: SM
authors.lastname: Saw
authors.forename: Tien-Yin
authors.initials: TY
authors.lastname: Wong
mesh_terms: D000328:Adult; D044466:Asian People / Q000706:statistics & numerical data*; D001794:Blood Pressure / Q000235:genetics; D002648:Child; D002675:Child, Preschool; D005260:Female; D006801:Humans; D008297:Male; D008833:Microcirculation; D008875:Middle Aged; D009216:Myopia / Q000208:ethnology* / Q000235:genetics*; D010290:Parents; D010641:Phenotype; D015995:Prevalence; D012171:Retinal Vessels / Q000033:anatomy & histology*; D012846:Singapore / Q000453:epidemiology
keywords: Singapore Chinese; familial correlation; retinal vascular caliber