Bozzetto L, et al. - Give the association of plasma apolipoprotein C3 (ApoC3) with higher plasma triglyceride and type 2 diabetes incidence, researchers examined the association of body mass index (BMI) or glucose metabolism with ApoC3 in healthy monozygotic (MZ) twins. They divided 47 MZ twin-pairs (20 man, 27 women; aged 23-42 years) in subgroups according to discordance or concordance for (a) BMI (within-pair difference (Δ) in BMI ≥ 3.0 or < 3.0 kg/m²), or (b) 2-h glucose iAUC, during oral glucose tolerance test (ΔGlucose iAUC ≥ 97.5 or < 97.5 mmol×120 minutes). No differences were noted in ApoC3 between leaner and heavier co-twins in BMI-Discordant or BMI-Concordant subgroups. In the Glucose-Discordant subgroup, significantly higher ApoC3 was observed in twins with higher Glucose iAUC than in their co-twins with the lower Glucose iAUC. In addition, higher waist circumference, body fat percentage, liver fat content, worse insulin-sensitivity and beta-cell function and higher cholesterol and triglyceride in plasma VLDL, IDL, and LDL were reported for co-twins with higher Glucose iAUC. These findings suggest no correlation of ApoC3 with acquired differences in BMI, but it was associated with early dysregulation of glucose metabolism. Obesity and genetic background did not influence this association.