Fig. 6: Metabolic variation across three populations.

a PCA plot of 153 significantly differentiated metabolites across three age-sex matched ethnic cohorts of 1146 individuals each (The first two PCs explain 23% of variation). Selection criteria for 153 metabolites include: 1) significantly associated with ethnicity in the discovery cohort (70% participants, two-sided linear regression analysis P < 1 × 10^-5 after multiple-test correction), and 2) significantly associated with ethnicity in the test cohort (30% participants, two-sided test P < 0.05 and same direction of estimates as in the discovery cohort). b Circos plot of 128 well-characterized and known metabolites (in sequence from outermost to innermost layer): 1) metabolite super-pathways, 2) significant associations with HT, Obs, T2D, and CVD, denoted by a black dot, 3) estimates of regression coefficient for association with ethnicities (CI: Indian compared to Chinese, CM: Malay compared to Chinese, IM: Malay compared to Indian). Curved lines at the centre highlight significant pairwise correlation between metabolites. Grey lines represent pairwise correlations within the same super-pathway; blue lines represent pairwise correlations across sub-pathways but within the same super-pathway; green lines represent pairwise correlations across super-pathways. c Violin plot showing contribution (as partial r-squared values) of age, dietary PCs, BMI, sex, and genetic PCs on variation of plasma abundance of 153 metabolites in 7546 individuals, with the outline indicating kernel probability density, the width of the shaded area represents the proportion of data located there. The embedded boxplot shows the median and interquartile range (box), with whiskers extending to 1.5 times the interquartile range. The inset plot zooms in on the partial r-squared distribution between 0.0–0.1. BMI body mass index, CVD cardiovascular disease, HT hypertension, Obs Obesity, PCA Principal Component Analysis, T2D type 2 diabetes.