Insulin secretion and sensitivity in black versus white prepubertal healthy children

• Published in: The Journal of clinical endocrinology and metabolism Vol. 82; no. 6; pp. 1923 - 1927
• Main Authors: ARSLANIAN, S, SUPRASONGSIN, C, JANOSKY, J. E
• Format: Conference Proceeding Journal Article
• Language: English
• Published: Bethesda, MD Endocrine Society 01-06-1997
• Subjects: African Continental Ancestry Group; Biological and medical sciences; Blood Glucose - analysis; Child; European Continental Ancestry Group; Female; Fundamental and applied biological sciences. Psychology; Glucose Clamp Technique; Hormone metabolism and regulation; Humans; Insulin - blood; Insulin - metabolism; Insulin Resistance; Insulin Secretion; Male; Mammalian female genital system; Osmolar Concentration; Puberty; Reference Values; Regression Analysis; Sex Characteristics; Vertebrates: reproduction; Human; Pancreatic hormone; Negroid; Insulin; Endocrine secretion; Protein hormone; Sensitivity; Prepuberty; Interindividual comparison; Race; Hormonal regulation; Hormonal investigation; Caucasoid; Child; Comparative study
• ISSN: 0021-972X; 1945-7197
• DOI: 10.1210/jc.82.6.1923

We had previously demonstrated greater insulin secretion and lower insulin sensitivity in black pubertal adolescents compared with whites. This study aimed to investigate whether similar black/white differences are present in the prepubertal period or are characteristics of the pubertal period. Twelve black and 11 white healthy prepubertal children, matched for age, body mass index, and Tanner I pubertal development, underwent a 2-h hyperglycemic clamp (225 mg/dL). Physical fitness was assessed by maximal oxygen consumption (VO2max) measurement during graded bicycle ergometry, and resting energy expenditure was measured by indirect calorimetry after overnight fast. Fasting and first phase insulin concentrations were higher in blacks than in whites [14.7 +/- 1.3 vs. 10.4 +/- 1.2 (P = 0.02) and 76.9 +/- 6.8 vs. 52.1 +/- 6.4 microU/mL (P = 0.016)]. There were no differences in second phase insulin levels and insulin sensitivity index. Both maximal oxygen consumption (VO2max) and resting energy expenditure were lower in black children, whereas insulin-like growth factor I was higher. After controlling for these differences, race contributed significantly to basal insulin, but not to first phase insulin. In summary, previously reported black/white differences in insulin secretion and sensitivity during adolescence may have their origin in early childhood manifested as hyperinsulinemia. However, genetic (race) vs. environmental factors (physical activity/fitness and energy balance) should be carefully scrutinized as potential factors responsible for such differences.