Heritability of retinal vessel diameters and blood pressure: a twin study.
OBJECTIVE
To assess the relative influence of genetic and environmental effects on retinal vessel diameters and blood pressure in healthy adults, as well as the possible genetic connection between these two characteristics.


METHODS
In 55 monozygotic and 50 dizygotic same-sex healthy twin pairs, aged 20 to 46 years, interpolated diameter estimates for the central retinal artery (CRAE), the central retinal vein (CRVE), and the artery-to-vein diameter ratio (AVR) were assessed by analysis of digital gray-scale fundus photographs of right eyes.


RESULTS
The heritability was 70% (95% CI: 54%-80%) for CRAE, 83% (95% CI: 73%-89%) for CRVE, and 61% (95% CI: 44%-73%) for mean arterial blood pressure (MABP). Retinal artery diameter decreased with increasing age and increasing arterial blood pressure. Mean vessel diameters in the population were 165.8 +/- 14.9 microm for CRAE, 246.2 +/- 17.7 microm for CRVE, and 0.67 +/- 0.05 microm for AVR. No significant influence on artery or vein diameters was found for gender, smoking, body mass index (BMI), total cholesterol, fasting blood glucose, or 2-hour oral glucose tolerance test values.


CONCLUSIONS
In healthy young adults with normal blood pressure and blood glucose, variations in retinal blood vessel diameters and blood pressure were predominantly attributable to genetic effects. A genetic influence may have a role in individual susceptibility to hypertension and other vascular diseases. The results suggest that retinal vessel diameters and the possible associated variations in risk of vascular disease are primarily genetic characteristics.
Taarnhøj
Nina C B B
NC
Department of Ophthalmology, Herlev Hospital, University of Copenhagen, Denmark. ninat@dadlnet.dk
Larsen
Michael
M
Sander
Birgit
B
Kyvik
Kirsten O
KO
Kessel
Line
L
Hougaard
Jesper L
JL
Sørensen
Thorkild I A
TI
D000328:Adult; D000367:Age Factors; D001786:Blood Glucose / Q000378:metabolism; D001794:Blood Pressure / Q000235:genetics*; D015992:Body Mass Index; D002784:Cholesterol / Q000097:blood; D003430:Cross-Sectional Studies; D004777:Environment; D005260:Female; D006801:Humans; D040582:Inheritance Patterns; D008297:Male; D008875:Middle Aged; D012161:Retinal Artery / Q000033:anatomy & histology* / Q000502:physiology; D012169:Retinal Vein / Q000033:anatomy & histology* / Q000502:physiology; D012737:Sex Factors; D014429:Twins, Dizygotic / Q000235:genetics*; D014430:Twins, Monozygotic / Q000235:genetics*
D001786:Blood Glucose; D002784:Cholesterol