Meet-in-the-middle meets multi-omics identifying molecular signatures of environmental drivers of childhood overweight.

BACKGROUND

Obesity is a multi-cause chronic disease recognized across the lifespan, with childhood obesity prevalence rising over the past decades. Although exposome-wide association studies have identified early-life environmental drivers of child obesity, and explored the multi-omics signatures of the exposome of children, it is understudied whether the combined effects of multiple exposures are potentially mediated by multi-omics.

METHODS

Within the Human Early Life Exposome (HELIX) project, 1041 mother-child pairs were surveyed for a wide range of environmental exposures including over 354 prenatal and childhood exposures. Multi-omics molecular features were measured during childhood, encompassing the blood methylome and transcriptome, plasma proteins and urinary and serum metabolites. Exposome and multi-omics features were integrated into latent factors by Multi-omics Factor Analysis, based on which structural equation modelling was used to assess whether multi-omics mediated associations between exposome and child body mass index (BMI).

RESULTS

Key findings included: (i) prenatal nutrition, exercise, and passive smoking influencing BMI via DNA methylation of HOXA5 and Tenascin XB; (ii) childhood exposure to PCBs and phenols linked with BMI through inflammation and coagulation pathways; and (iii) childhood PCB and dietary exposures associated with BMI via immune pathways.

CONCLUSIONS

This novel untargeted workflow elucidated biological mechanisms linking environmental exposures to child obesity, potentially supporting targeted public health interventions.