Effects of Physical Activity and Inactivity on Microvasculature in Children: The Hong Kong Children Eye Study

Abstract

<p><span>Purpose</span>: The purpose of this study was to investigate the effects of physical activity and inactivity on the microvasculature in children, as measured from retinal photographs.</p><p><span>Methods</span>: All participants were from the Hong Kong Children Eye Study, a population-based cross-sectional study of children aged 6 to 8 years. They received comprehensive ophthalmic examinations and retinal photography. Their demographics and involvement in physical activity and inactivity were obtained from validated questionnaires. A validated Deep Learning System was used to measure, from retinal photographs, central retinal arteriolar equivalent (CRAE) and central retinal venular equivalent (CRVE).</p><p><span>Results</span>: In the final analysis of 11,959 participants, 6244 (52.2%) were boys and the mean age was 7.55 (1.05) years. Increased ratio of physical activity to inactivity was associated with wider CRAE (<em>β</em> = 1.033, <em>P</em> = 0.007) and narrower CRVE (<em>β</em> = –2.079, <em>P</em> < 0.001). In the subgroup analysis of boys, increased ratio of physical activity to inactivity was associated with wider CRAE (<em>β</em> = 1.364, <em>P</em> = 0.013) and narrower CRVE (<em>β</em> = –2.563, <em>P</em> = 0.001). The subgroup analysis of girls also showed increased ratio of physical activity to inactivity was associated with narrower CRVE (<em>β</em> = –1.759, <em>P</em> = 0.020), but not CRAE.</p><p><span>Conclusions</span>: Increased activity in children is associated with healthier microvasculature, as shown in the retina. Our study contributes to the growing evidence that physical activity positively influences vascular health from a young age. Therefore, this study also underscores the potential of using the retinal vasculature as a biomarker of cardiovascular health.</p>