Fasting Insulin Level in Obese Children: Relationship to Comorbidities of Childhood Obesity

Kim, Soo Young; Shin, Dong Han; Kim, Hyung Jin; Eun, Baik Lin; Park, Sang Hee; Cha, Sang Hoon; Lee, Kee Hyoung

Abstract

PURPOSE
It is well known that childhood obesity associated with high morbidity of hyperlipidemia, hypertension, fatty liver and type 2 diabetes mellitus. Recently investigators have revealed that hyperinsulinemia in obese children is related with not only insulin resistance but also hyperlipidemia and fatty liver. We investigated the relationship between fasting insulin level and comorbidities of childhood obesity. Also we determined the prevalence of asymptomatic fatty liver and presumed nonalcoholic steatohepatitis and to assess the correlation of fatty liver with degree of obesity and serum insulin level.
METHODS
We measured fasting serum insulin in 300 obese children (obesity index greater than 20 percent), from 8 to 15 years old age and blood pressure, fasting serum glucose and lipid profiles were also checked. Fatty liver was diagnosed by liver function test and abdominal ultrasonography. The correlations of insulin with BMI, blood pressure and lipid profiles were analyzed by linear regression. The prevalences of hypertension, hyperlipidemia and fatty liver were compared according to fasting insulin level.
RESULTS
Mean obesity index of obese children was 35.26 (37.01 in male, 31.61 in female). Mean body mass index of obese children was 26.15 kg/m2 (26.72 kg/m2 in male, 24.98 kg/m2 in female). Among obese children, 87 children had hypercholesterolemia (>or=200 mg/dL, 28.9%), 60 children had hypertriglyceridemia (>or=150 mg/dL, 20.0%), 128 children had fatty liver (42.7%) and 139 children had hyperinsulinemia (46.6%). Serum insulin level had positive correlation with body mass index (r=0.274, P>0.01), systolic blood pressure (r=0.291, P<0.01), serum triglyceride (r=0.339, P<0.01) and not with serum total cholesterol. The prevalences of hypertriglyceridemia and fatty liver were higher in obese children with hyperinsulinemia than with normal insulin level (P<0.01). The severity of fatty liver was positively related to BMI, obesity index, triglyceride, insulin, HOMA. Fatty liver with elevated ALT was found in 40 subjects (13.3%).
CONCLUSION
In this study, fasting insulin level had closely related with dyslipidemia and fatty liver in obese children. Our results suggest that monitoring of insulin level is helpful to assess the morbidities and should become a part of routine care of obese children.