title: Body mass index and its effects on retinal vessel diameter in 6-year-old children.
abstract: OBJECTIVE
  To examine the relationship between body mass index (BMI) and other anthropometric measures with retinal vessel diameter in children.
  
  
  METHODS
  A random cluster sample of 34 schools was selected in the Sydney metropolitan area during 2003-04, and 1740 children aged 6 years participated in The Sydney Childhood Eye Study. Retinal images were taken and vessel diameter was measured using a computer-imaging program. Anthropometric measures, including weight, height, waist circumference, BMI and body surface area (BSA), were obtained and defined using standardized protocols. Data on confounders, including ocular parameters, ethnicity, birth parameters and blood pressure, were similarly collected.
  
  
  RESULTS
  Mean BMI was 16.2 kg/m(2) (+/-2.1 s.d.) in 1608 (92.4%) children with complete data. After controlling for age, sex, ethnicity, axial length of the eyeball, birth weight and mean arterial blood pressure, children with BMI above the cardiovascular risk threshold (defined as BMI>16.1 kg/m(2) in boys and BMI>15.9 kg/m(2) in girls) had mean retinal venular diameter 2.1 microm larger than those with BMI below this threshold (P=0.026). Increasing weight and BSA were also positively associated with wider retinal venules. Children in the highest quartile of BMI had mean retinal arteriolar diameter 2.2 microm smaller than those in the lowest quartile. Increasing waist circumference and shorter height were also associated with narrower retinal arterioles.
  
  
  CONCLUSIONS
  In this sample of 6-year-old children, greater BMI, weight and BSA were associated with wider retinal venules, while greater BMI and larger waist circumference were associated with narrower retinal arterioles. These findings suggest a possible effect of increased body mass and adiposity on early microvascular structural alterations in childhood, long before the development of cardiovascular disease.
authors.affiliation: Centre for Vision Research, Department of Ophthalmology, Westmead Millennium Institute, Westmead Hospital, University of Sydney, Sydney, New South Wales 2145, Australia.
authors.forename: B
authors.initials: B
authors.lastname: Taylor
authors.forename: E
authors.initials: E
authors.lastname: Rochtchina
authors.forename: J J
authors.initials: JJ
authors.lastname: Wang
authors.forename: T Y
authors.initials: TY
authors.lastname: Wong
authors.forename: S
authors.initials: S
authors.lastname: Heikal
authors.forename: S M
authors.initials: SM
authors.lastname: Saw
authors.forename: P
authors.initials: P
authors.lastname: Mitchell
mesh_terms: D000886:Anthropometry; D001160:Arterioles / Q000033:anatomy & histology*; D015992:Body Mass Index; D002648:Child; D003430:Cross-Sectional Studies; D005123:Eye / Q000098:blood supply*; D005260:Female; D006801:Humans; D008297:Male; D012171:Retinal Vessels / Q000033:anatomy & histology*