LDL particle size, fat distribution and insulin resistance in obese children

Background: The importance of small dense low-density lipoprotein (sdLDL) cholesterol in coronary heart disease has been demonstrated in many studies. Body fat accumulation, especially abdominal adiposity, is one of the important factors modifying the expression of sdLDL in adults. Objective: To determine the prevalence of sdLDL in obese children, and to investigate its relationship with anthropometric and metabolic variables. Subjects: A total of 30 obese children ( 22 males, 8 females) aged 12.6 +/- 0.6 years (mean +/- s.e.), who presented to our outpatient clinic with obesity. Methods: LDL peak particle diameter was determined using gel electrophoresis. LDL subclasses were classified into sdLDL ( pattern B; diameter <25.5 nm) and non-sdLDL ( pattern A; diameter >= 25.5 nm). Anthropometric and metabolic variables were also determined to identify factors modifying LDL particle size. Results: sdLDL was detected in 11 children (40.0%). In children with sdLDL, waist/height ratio was significantly higher ( P = 0.0466), and they had significantly higher triglyceride (TG) ( P = 0.0035) and lower high-density lipoprotein cholesterol (HDLC) levels ( P = 0.036). Peak LDL diameter as a continuous variable was significantly correlated with HDLC and TG levels. In multiple regression analysis, body mass index and waist/height ratio were significant determinants of the peak LDL diameter variability. Conclusions: We found a high prevalence of sdLDL in obese children, and a relationship of peak LDL diameter with abdominal fat accumulation, HDLC and TG levels. The presence of sdLDL might be an important risk factor for the metabolic syndrome.