Association between chest-to-head circumference ratio at birth and childhood neurodevelopment: the Japan Environment...

Children born growth-restricted are well recognized to be at an increased risk of poor neurodevelopmental outcomes. This prospective study examined the influence of chest-to-head circumference ratio at birth on neurodevelopment in the first three years among children enrolled in the Japan Environment and Children's Study. We analyzed information of 84,311 children (43,217 boys, 41,094 girls). Children were divided into low, normal, and high chest-to-head circumference ratio groups. Neurodevelopment was assessed every six months (from 6 months to 3 years) using the Ages and Stages Questionnaire (Japanese translation), with delays defined as scores below 2 standard deviations from the mean. Additionally, we evaluated the contributions of chest and head circumference to the observed association. Linear mixed-effect regression revealed increased risk of delays in communication, gross motor, fine motor, problem-solving, and personal-social skills in the low-ratio group compared to the normal-ratio group. Adjusted risk ratios were in the range of 1.14 - 1.39 in boys and 1.16 - 1.37 in girls, with no such increase observed in the high-ratio group. The heightened risk in the low-ratio group was likely associated with a relatively narrow chest rather than a large head. The area under the ROC curves in predicting any developmental delay at three years for newborn measurements ranged from 0.513 to 0.526 in boys and 0.509 to 0.531 in girls. These findings suggest that a low chest-to-head circumference ratio may indicate children who are at risk for neurodevelopmental deficits. However, the ability to predict poor neurodevelopmental outcomes at three years of age is limited.