Phenotypic and genetic correlation of blood pressure and body mass index with retinal vascular caliber in children and adolescents: the Guangzhou twin eye study.

PURPOSE

To examine the phenotypic and genetic associations of blood pressure and body mass index (BMI) with retinal vascular caliber.

METHODS

A total of 657 monozygotic and 378 dizygotic twin pairs aged 7 to 19 years were recruited from the Guangzhou Twin Registry. All twins underwent digital retinal photography and measurement of retinal vascular caliber. The genetic correlations between the traits were estimated by applying a multivariate Cholesky model.

RESULTS

In traditional regression analyses, participants with a higher mean arterial pressure (MAP) and a higher BMI were significantly more likely to have narrower retinal arterioles, whereas participants with a higher BMI level were more likely to have a wider retinal venule (all P < 0.001). In multivariate Cholesky models, only 1% to 2% of the phenotypic variation in retinal arteriole was shared with those in MAP and BMI, although the majority of these phenotypic variations were explained by shared genetic components. The phenotypic variation in retinal venule was not shared with those in MAP and BMI.

CONCLUSIONS

Retinal vascular caliber is significantly but weakly associated with MAP and BMI in children and young adolescents. These phenotypic correlations are mainly attributable to genetic components.