Background Recent studies demonstrated that low‐density lipoprotein‐tryglyceride (LDL‐TG) may represent another marker of cardiovascular risks. We therefore measured LDL‐TG including the low‐density lipoprotein (LDL) subclass distribution and investigated the association between LDL‐TG subclass profile and the clustering of metabolic syndrome (MetS) components and insulin resistance in Japanese children. Methods The study included 237 schoolchildren (boys 115, girls 122). Four subclasses of low‐density lipoprotein‐tryglyceride (large, medium, small, and very small) was quantified using high‐performance liquid chromatography. Total LDL‐TG and TG levels in LDL subclasses were evaluated among four MetS component groups; non‐abdominal obesity, abdominal obesity, pre‐MetS, and MetS. Results Total LDL‐TG (P = 0.0003, P = 0.0175) and triglyceride levels in LDL subclasses were significantly different among four MetS component groups (large: P = 0.0002, P = 0.0084; medium: P = 0.0009, P = 0.0491; small: P =0.0025, P = 0.0509; very small: P = 0.0808, P = 0.0228; boys and girls, respectively). Total LDL‐TG (r = 0.411, P < 0.0001, r = 0.378. P < 0.0001) and triglyceride levels in LDL subclasses correlated positively with the homeostasis model of assessment ratio (large: r = 0.396, P < 0.0001, r = 0.346, P < 0.0001; medium: r = 0.274, P = 0.0030, r = 0.228, P = 0.0115; small: r = 0.342, P = 0.0002, r = 0.292, P = 0.0011; very small: r = 0.385, P < 0.0001, r = 0.426, P < 0.0001, boys and girls, respectively). Conclusions Subclass distribution of LDL‐TG was significantly associated with the clustering of MetS components in both sexes, and insulin resistance is a significant determinant of LDL‐TG in all LDL subclasses. Lipoprotein‐tryglyceride subclass analysis, rather than LDL‐C, may provide a precise evaluation for cardiovascular disease risks in children with MetS.

Abdominal bioelectrical impedance analysis (aBIA) has been in use to measure visceral fat area (VFA) in adults. Accurately measuring visceral fat using aBIA in children is challenging. Forty-six school-aged Japanese children aged 6–17 years (25 boys and 21 girls) were included in this study. All were measured, and their VFA obtained using aBIA (VFA-aBIA) and abdominal computed tomography (CT) (VFA-CT) were compared. VFA-aBIA was corrected using the Passing–Bablok method (corrected VFA-aBIA). The relationships between corrected VFA-aBIA and obesity-related clinical factors were analyzed, including non-alcoholic fatty liver disease (NAFLD) and serum leptin and adiponectin levels. Boys had higher VFA-CT than girls (p = 0.042), although no significant differences were found in their waist circumference, waist-to-height ratio, and body mass index. The corrected VFA-aBIA using y = 9.600 + 0.3825x (boys) and y = 7.607 + 0.3661x (girls) correlated with VFA-CT in both boys and girls. The corrected VFA-aBIA in patients with NAFLD was higher than that in those without NAFLD. Serum leptin and adiponectin levels were positively and negatively correlated with corrected VFA-aBIA, respectively. In conclusion, corrected VFA-aBIA was clearly correlated with VFA-CT and was related to NAFLD and serum leptin and adiponectin levels in school-aged Japanese children.