Ectopic Fat in Youth: The Contribution of Hepatic and Pancreatic Fat to Metabolic Disturbances

Objective: To study the relationships between parameters of glucose and insulin metabolism and visceral and abdominal ectopic fat in youth. Methods: A cross sectional study of 50 children (24 females), 8-18 years old. Anthropometrics, body composition, blood-work and visceral and ectopic fat by magnetic resonance imaging were assessed. Insulin secretion, insulin sensitivity and beta cell function were calculated from an oral glucose tolerance test. Results: BMI z-scores ranged between -1.3 and 4.5. The hepatic fat fraction (HFF) ranged between 0 and 36% and pancreatic fat fraction (PFF) between 0 and 14%. Visceral fat, HFF and PFF were associated with clinical and biochemical metabolic abnormalities, and correlated with markers of insulin sensitivity (r = 20.60, P < 0.01; r = 20.64, P < 0.01; r = 20.48, P < 0.01, respectively) insulin secretion (r = 0.55, P < 0.01; r = 0.57, P < 0.01; r = 0.41, P < 0.01, respectively), and beta cell function (r = 20.49, P < 0.01; r = 20.59, P < 0.01; r = 20.39, P < 0.01, respectively). Conclusions: Accumulations of pancreatic and hepatic fat have complementary clinical consequences in youth. While visceral and hepatic fat demonstrated a dominant effect, even relatively small degrees of pancreatic fat deposition may contribute to metabolic alterations.