Body Mass Index Mediates the Association between Growth Trajectories and Cardiometabolic Risk in Children

Abstract

Background: Few studies have published mediation analyses to quantify the role concurrent BMI plays in the relationship between growth and cardiometabolic risk (CMR) outcomes. Methods: We used data from a longitudinal cohort study conducted in children aged 0-60 months through The Applied Research Group for Kids (TARGet Kids!) in Canada. Four age and sex standardized BMI (zBMI) trajectories were identified using latent class mixed models. CMR were assessed using a CMR score. Concurrent zBMI was the zBMI measured on the same visit as CMR. Mediation analyses were performed comparing each trajectory with the reference trajectory. Results: One thousand one hundred sixty-five children were included. On average, compared with being in the stable low trajectory, being in the catch-up trajectory was associated with an increased CMR score of 0.42, 0.28 of which was mediated through concurrent zBMI [95% confidence interval (CI) 0.17 to 0.41, p = 0.001]; being in the stable high trajectory was associated with an increased CMR score of 0.23, 0.24 through concurrent zBMI (95% CI 0.18 to 0.31, p < 0.001). Similarly, being in the rapid accelerating trajectory was associated with an increased CMR score of 1.43, 1.18 of which was through concurrent zBMI (95% CI 0.89 to 1.50, p < 0.001). Conclusions: There was a strong evidence that the effect of BMI trajectories on CMR was indirect via concurrent BMI. It is important for researchers to choose the most appropriate analytic method based on the study hypothesis to understand the total or direct effect of growth patterns on cardiometabolic disease risk in children.

Keywords: cardiometabolic risk; early childhood; growth; mediation analysis; mediator.