Endocrine Abstracts

Background: IRS consists of ≥3 of the following components: obesity (BMI >98th centile), abnormal insulin glucose homeostasis, hypertension, dyslipidaemia. Elevated serum alanine aminotransferase (ALT) is a marker of NAFLD.

Objective: To define the prevalence of IRS and NAFLD in obese children referred to our centre.

Methods: subjects: mean BMI-SDS +6 (+0.6 to +14), median age 13.4 years (3–19), female 66%, British Asian 24%, underwent an oral glucose tolerance test with results categorised by WHO criteria: impaired fasting glucose (IFG), impaired glucose tolerance (IGT), T2DM. Fasting hyperinsulinaemia (FH) and 120 minute hyperinsulinaemia (HI) were defined >26 and >95 mIU/l respectively. HOMA-IR was calculated (normal <2.5). Fasting lipids were measured in 42, ALT in 29 and blood pressure in 24. Abnormalities were defined: cholesterol > 95th centile for age and sex, triglycerides ≥ 1.75 mmol/l, ALT>45 IU/l, systolic BP> 95th centile for age and sex.

Results: Abnormalities of glucose and insulin homeostasis were observed in: IFG 4%, IGT 13%, T2DM 6% (only one child with IGT was identified with IFG), HOMA-IR >2.5 78%, FH 42%, HI 38% and acanthosis nigricans 40%. British Asians were more likely than British White to have acanthosis nigricans (OR 4.1, 95%CI 1.3–12.7). Elevated lipids, ALT and BP were identified in 33.5% (cholesterol 9.5%, triglycerides 24%), 42% and 54% respectively. BP was correlated with BMI (r² =0.17, P=0.05) and HOMA-IR contributed 16% to the variance of ALT (P=0.04). Controlling for age and puberty, HOMA-IR was determined by female sex (P=0.002), acanthosis nigricans (P=0.002) and BMI-SDS (P=0.04). 36% had obesity alone, 43% had 2 components IRS and 21% had ≥3 components IRS. The number of components of IRS was determined by increasing age (P=0.03) and family history of T2DM (P=0.02).

Conclusion: In obese children, female sex, British Asian background, increasing age and family history of T2DM appear to be risk factors for IRS. Increased insulin resistance was observed in children with NAFLD.