Obesity and the development of insulin resistance and impaired fasting glucose in black and white adolescent girls: a longitudinal study.
OBJECTIVE
Age at onset of type 2 diabetes has decreased during the past 20 years, especially in black women. Studies of factors associated with insulin resistance and hyperglycemia in preadolescent and adolescent populations are essential to understanding diabetes development.


METHODS
The National Heart, Lung, and Blood Institute (NHLBI) Growth and Health Study (NGHS) is a 10-year cohort study of the development of obesity in black and white girls. Two NGHS centers examined the associations of obesity, puberty, and race with fasting insulin, glucose, and homeostasis model assessment of insulin resistance (HOMA-IR; a calculated index of insulin resistance) measures at 9-10 years of age (baseline) and 10 years later.


RESULTS
Black girls had greater baseline and year-10 BMI than white girls, with a greater 10-year incidence of obesity. BMI-insulin correlations were positive in both black and white girls at both visits, but insulin remained higher in black girls after controlling for BMI. In black girls, insulin and HOMA-IR were higher in the prepubertal period (before the emergence of racial differences in BMI), increased more during puberty, and decreased less with its completion. Baseline BMI predicted year-10 glucose and the development of impaired fasting glucose (IFG) in black girls. In white girls, the rate of BMI increase during follow-up predicted these outcomes. The 10-year incidence of diabetes in black girls was 1.4%.


CONCLUSIONS
Black-white differences in insulin resistance are not just a consequence of obesity, but precede the pubertal divergence in BMI. The development of IFG appears to be a function of the rate of increase of BMI in white girls and early obesity in black girls.
Klein
David J
DJ
Division of Endocrinology and Cardiology, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio 45229, USA.
Aronson Friedman
Lisa
L
Harlan
William R
WR
Barton
Bruce A
BA
Schreiber
George B
GB
Cohen
Robert M
RM
Harlan
Linda C
LC
Morrison
John A
JA
D000293:Adolescent; D044383:Black People; D001786:Blood Glucose / Q000032:analysis / Q000378:metabolism*; D015992:Body Mass Index; D002648:Child; D003431:Cross-Cultural Comparison; D005260:Female; D018149:Glucose Intolerance / Q000453:epidemiology*; D006706:Homeostasis; D006801:Humans; D007328:Insulin / Q000097:blood* / Q000378:metabolism; D007333:Insulin Resistance / Q000502:physiology*; D008137:Longitudinal Studies; D009316:National Institutes of Health (U.S.); D009765:Obesity / Q000097:blood / Q000453:epidemiology*; D012044:Regression Analysis; D014481:United States; D044465:White People; D001741:Black or African American
D001786:Blood Glucose; D007328:Insulin