The role of the metabolic profile in mediating the relationship between body mass index and left ventricular mass in adolescents: analysis of a prospective cohort study

Background: We aimed to quantify the role of the plasma metabolic profile in explaining the effect of adiposity on cardiac structure.

Methods and results: Body mass index (BMI) was measured at age 11 in the Avon Longitudinal Study of Parents and Children. Left ventricular mass indexed to height2.7 (LVMI), was assessed by echocardiography at age 17. The metabolic profile was quantified via 1H-nuclear magnetic resonance (NMR) spectroscopy at age 15.

Multivariable confounder (maternal age, parity, highest qualification, maternal smoking, pre-pregnancy BMI, pre-pregnancy height, household social class and adolescent birthweight, adolescent smoking, fruit and vegetable consumption, physical activity) -adjusted linear regression estimated the association of BMI with LVMI and mediation by metabolic traits. We considered 156 metabolomic traits individually, jointly as principal components (PCs) explaining 95% of the variance in the NMR platform, and assessed whether the PCs for the metabolic traits added to the proportion of the association explained by putative cardiovascular risk factors (systolic and diastolic blood pressures, insulin, triglycerides, low density lipoprotein, and glucose).

A 1kg/m2 higher BMI was associated with a 0.70 g/m2.7 (0.53, 0.88) and 0.66 g/m2.7 (0.53, 0.79) higher LVMI in males (N=437) and females (N=536), respectively. Putative risk factors explained 3% (95% CI: 2% to 5%) of this association in males, increasing to 10% (95% CI: 8%, 13%) when including metabolic PCs. In females, the standard risk factors explained 3% (95% CI: 2%, 5%) of the association, and did not increase when including the metabolic PCs.

Conclusion: The addition of the NMR-measured metabolic traits appear to mediate more of the association of BMI on LVMI than the putative risk factors alone in adolescent males, but not females.