Impact of Size at Birth on the Microvasculature: The Avon Longitudinal Study of Parents and Children

BACKGROUND. The impact of early life factors on the microvasculature is relatively unknown. OBJECTIVES. We hypothesized that small birth size may be associated with structural variations in the retinal vasculature in children. METHODS. The Avon Longitudinal Study of Parents and Children followed a cohort of children born in 1991–1992 from birth. The current study included the first 263 children who were systematically screened in the year-12 follow-up. Complete data were available for 166 children with a gestation of ≥37 weeks. Retinal circulatory measures were evaluated, including retinal microvascular tortuosity and bifurcation optimality deviance, an indicator of abnormal endothelial function. RESULTS. Optimality deviance and retinal tortuosity were higher among those with lower birth weight. Linear regression modeling was used to assess the association of retinal microvascular measures with birth weight. The standardized β coefficient between optimality deviance and birth weight was –.182 adjusted for gender and age in weeks; additional adjustment for systolic blood pressure and heart rate had little impact on the β coefficient. A similar association was observed for retinal tortuosity. CONCLUSION. The findings of this study suggest that early life factors may have an important impact on retinal vascular structure, possibly through an adverse effect on endothelial function.