Table 1.

Key terms and concepts.

Term/concept	Explanation
Infancy body mass index (BMI) peak	An individual-level BMI trajectory milestone characterized by a vertex that typically occurs between 7 and 9 months of age. Later age and higher magnitude of this milestone has been associated with future obesity and metabolic risk.
Childhood BMI rebound	An individual-level BMI trajectory milestone characterized by a nadir that typically occurs between 3 and 6 years of age. Earlier age and higher magnitude of this milestone has been related to future obesity and metabolic risk.
False discovery rate (FDR)	A statistical procedure that protects against type 1 error (i.e., false positive findings) when making multiple comparisons. The correction requires an investigator-defined threshold of acceptable type 1 error. In this study, we used an error rate of 5%.
Untargeted metabolomics platform	An unbiased laboratory approach to measuring low-molecular-weight compounds (metabolites) in a biosample. This type of platform typically involves mass spectrometry (MS) paired with liquid (LC) and/or gas chromatography (GC) to estimate relative concentrations of all detectable metabolites (from hundreds to thousands) in a biosample. The broad coverage of this type of platform makes it ideal for hypothesis generation and discovery of new biomarkers.
Metabolic syndrome (MetS) z-score	A metabolic syndrome risk z-score calculated as the average of externally age- and sex-standardized waist circumference, systolic blood pressure, reversed high-density lipoprotein (HDL), the homeostatic model assessment of insulin resistance (HOMA-IR), and triglycerides.
Weighted correlation network analysis (WGCNA)	A correlation-based dimension reduction procedure that constructs latent variables (“consensus networks”) that account for the majority of variability in a high-dimensional dataset.
Meeting-in-the-middle	An analytical strategy that involves identifying a features (e.g., metabolites) from a high-dimensional dataset (e.g., untargeted metabolomics data) that are associated with an exposure, and also associated with an outcome.