2.5 | Statistical analysis
Student’s t-test, non-parametric Mann-Whitney U test, Chi-square test,
and Fisher’s exact test were performed to investigate maternal clinical
characteristics using R programming. The Kruskal-Wallis test and Post
hoc comparisons were applied to compare neonatal clinical
characteristics between DCDA-C, DCDA-D-L, and DCDA-D-S. The Uniform
Manifold Approximation and Projection (UMAP) was used to compare the
hair metabolome profiles between three twin groups using uMAP and
ggplot2 R-packages. The hair metabolite profiles were adjusted by log
transformation and Pareto scaling to ensure the Gaussian distribution of
the hair dataset prior to statistical analysis. The adjusted logistic
regression models were applied to eliminate the confounding effect of
gestation age. Metabolic pathway activities were estimated using
identified metabolites by Metaboanalyst 5.0. Moreover, the metabolic
network was in silico reconstruction based on KEGG metabolic
framework using the Metascape package in Cytoscape (Version 3.9.1).
Pearson’s correlation was executed to determine the correlation between
hair metabolite levels, metabolic pathways, physical development
indices, and five developmental domains of ASQ-3. The metabolic
heatmaps, pathway activity plots, and circus plots were illustrated by
pheatmap, ggplot2, and GOplot R-packages.