Influence of physical fitness and activity behavior on retinal vessel diameters in primary schoolchildren.

Retinal vessel alterations have been shown to be associated with cardiovascular risk factors and physical inactivity as early as childhood. In this context, the analysis of physical activity in children has solely been based on questionnaire assessments. The study aimed to examine the association of physical fitness performance and self-reported physical activity with retinal vessel diameters in young children. Three hundred ninety-one primary schoolchildren [7.3 years (SD 0.4)] were examined in this cross-sectional study. The primary outcome was endurance performance measured with the 20-m shuttle run. The additional tests consisted of a 20-m sprint, jumping sidewards and balancing backwards. Retinal microcirculation was assessed using a static retinal vessel analyzer. Parents completed questionnaires about physical and sedentary activities. Endurance performance was associated with narrower retinal venular diameters [-0.9 (95%CI: -1.8; -0.1) measuring units (mu)/ unit shuttle run, P = 0.04] and a higher arteriolar to venular ratio [0.003 (-0.001; 0.006)/unit shuttle run, P = 0.06]. The sprint performance was associated with narrower retinal arterioles [4.7 (0.8; 8.6) mu/unit sprint, P = 0.02]. Indoor playing activity correlated with narrower retinal venules [-0.04 (-0.07; -0.01) mu/per unit, P = 0.02]. Our data suggest that objectively measured endurance performance relates with better retinal vessel health in early childhood.