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Age‐Related Changes in Insulin Sensitivity and β‐Cell Function Among European‐American and African‐American Women
Author(s) -
ChandlerLaney Paula C.,
Phadke Radhika P.,
Granger Wesley M.,
Fernández José R.,
Muñoz Julian A.,
Man Chiara Dalla,
Cobelli Claudio,
Ovalle Fernando,
Gower Barbara A.
Publication year - 2011
Publication title -
obesity
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.438
H-Index - 199
eISSN - 1930-739X
pISSN - 1930-7381
DOI - 10.1038/oby.2010.212
Subject(s) - medicine , endocrinology , overweight , basal (medicine) , insulin resistance , type 2 diabetes , obesity , insulin , diabetes mellitus
Type 2 diabetes (T2D) is more prevalent among African‐American (AA) than European‐American (EA) women for reasons that are unknown. Ethnic differences in physiological processes related to insulin sensitivity (S I ) and secretion, and age‐related changes in these processes, may play a role. The purpose of this study was to identify ethnicity‐ and age‐related differences in S I and β‐cell responsivity among AA and EA females, and to determine whether these differences are independent of body composition and fat distribution. Healthy, normoglycemic females aged 7–12 years ( n = 62), 18–32 years ( n = 57), and 40–70 years ( n = 49) were recruited for entry into this study. Following an overnight fast, S I , intravenous glucose tolerance (Kg), acute C‐peptide secretion (X0), and basal, first‐phase, second‐phase, and total β‐cell responsivity to glucose (PhiB, Phi1, Phi2, and Phi TOT , respectively) were measured by an intravenous glucose tolerance test. Total % body fat was assessed by dual‐energy X‐ray absorptiometry, and intra‐abdominal adiposity (IAAT) by computed tomography. Main effects of age group and ethnicity were measured with analysis of covariance, adjusting for % fat, IAAT, and S I as indicated. AA had lower S I , and higher Kg, X0, Phi1, and Phi TOT ( P < 0.05), which remained after adjustment for % fat and IAAT. Greater X0, Phi1, and Phi TOT among AA were independent of S I . Advancing age was associated with greater Phi2 among both EA and AA. To conclude, inherent ethnic differences in β‐cell function exist independently of adiposity and S I . Future research should examine whether ethnic differences in β‐cell physiology contribute to disparities in T2D risk.