Longitudinal changes in insulin sensitivity, insulin secretion, and beta-cell function during puberty.
OBJECTIVE
To determine longitudinal changes in insulin sensitivity (SI), insulin secretion, and beta-cell function during puberty in white and black youth.


METHODS
The tolbutamide-modified frequently sampled intravenous glucose tolerance test and minimal modeling were used to measure SI, the acute insulin response to glucose (AIRg), and beta-cell function (disposition index, DI) in white (n = 46) and black (n = 46) children (mean [+/-SD] age at baseline = 10.2 +/- 1.7 years). Growth curve models (including 272 observations) with SI, AIRg, and DI regressed on Tanner stage were run after adjusting for covariates.


RESULTS
After adjusting for covariates, growth curve models revealed that SI decreased and subsequently recovered by the end of puberty in whites and blacks (both p < .05), AIRg decreased linearly across Tanner stages in both races (both p < .001), and DI decreased across puberty in blacks (p = .001) but not in whites (p = .2).


CONCLUSIONS
White and black youth exhibited transient insulin resistance and diminished AIRg during puberty. The progressive decline in DI among blacks versus whites may reflect a unique effect of puberty on beta-cell compensation in blacks. Future studies are needed to identify whether this difference contributes to the increased risk of type II diabetes in young blacks.
Ball
Geoff D C
GD
Department of Preventive Medicine, University of Southern California, Los Angeles, USA.
Huang
Terry T-K
TT
Gower
Barbara A
BA
Cruz
Martha L
ML
Shaibi
Gabriel Q
GQ
Weigensberg
Marc J
MJ
Goran
Michael I
MI
D001741:Black or African American; D001786:Blood Glucose / Q000378:metabolism; D001837:Body Weights and Measures; D016009:Chi-Square Distribution; D002648:Child; D002675:Child, Preschool; D004734:Energy Metabolism / Q000502:physiology; D005260:Female; D005951:Glucose Tolerance Test; D006801:Humans; D007328:Insulin / Q000378:metabolism*; D007333:Insulin Resistance / Q000502:physiology*; D000078790:Insulin Secretion; D050417:Insulin-Secreting Cells / Q000378:metabolism* / Q000502:physiology; D008137:Longitudinal Studies; D008297:Male; D011627:Puberty / Q000208:ethnology / Q000502:physiology*; D012044:Regression Analysis; D044465:White People
D001786:Blood Glucose; D007328:Insulin