Smaller birth size is associated with narrower retinal arterioles in early adolescence

In the current study, we aimed to examine the associations of low birth weight with retinal vascular caliber and vascular fractal dimension during early adolescence.

A population-based study of 12-year-old schoolchildren (2353/3144 [75.3%]) recruited from a random cluster sample of 21 schools. Birth weight, birth length and head circumference were obtained via parent report of the child's birth record. Retinal images were taken and vessel diameter and fractal dimension were quantified using validated computer-based methods.

After adjusting for age, sex, ethnicity, body mass index, iris color, axial length, mean arterial blood pressure, prematurity and fellow retinal vascular caliber, children in the lowest quartiles of birth weight had ∼2.5 μm narrower mean retinal arteriolar caliber than those in the highest quartiles (p for trend = 0.001). Associations were observed between shorter birth length and smaller head circumference with narrower retinal arterioles. Smaller head circumference was associated with decreased fractal dimension (p for trend = 0.03).

Children with lower birth weight were more likely to have narrower retinal arterioles, while those with smaller head circumference were more likely to have reduced complexity of their retinal microvasculature. These variations in microvascular structure in adolescence could reflect a susceptibility to cardiovascular disease during adulthood, resulting from a disadvantaged growth environment in utero.