Influence of gestational diabetes on the long-term control of glucose tolerance.
OBJECTIVE
Gestational diabetes (GDM) carries a high risk of subsequent diabetes. We asked what impact prior GDM has on beta cell function and insulin action in women who maintain normal glucose tolerance (NGT) for a long time.


METHODS
Ninety-one women with NGT (aged 41 +/- 8 years, mean+/-SD) were studied (by mathematical modelling of the C-peptide response to an OGTT) 7 [6] years (median [interquartile range]) after the index pregnancy, during which 52 had GDM (pGDM) and 39 had NGT (pNGT). In all women an OGTT had also been performed at 29 +/- 3 weeks of the index pregnancy.


RESULTS
Women with pGDM were matched with women with pNGT for age, familial diabetes, time and weight gain since index pregnancy, parity, BMI (25.4 +/- 3.9 vs 26.8 +/- 6.4 kg/m(2)), and fasting (4.64 +/- 0.56 vs 4.97 +/- 0.46 mmol/l) and 2 h plasma glucose levels (5.91 +/- 1.14 vs 5.91 +/- 1.21 mmol/l). Nonetheless, fasting (49 [29] vs 70 [45] pmol min(-1) m(-2), p < 0.001) and total insulin secretion (32 [17] vs 48 [21] nmol m(-2), p < 0.0001) and beta cell glucose sensitivity (slope of the insulin secretion/plasma glucose concentration-response function) (95 [71] vs 115 [79] pmol min(-1) m(-2) (mmol/l)(-1), p = 0.025) were reduced in the pGDM group compared with the pNGT group, while insulin sensitivity was preserved (424 [98] vs 398 [77] ml min(-1) m(-2)). At index pregnancy, women with pGDM and those with pNGT had similar age and BMI. However, both insulin sensitivity (359 [93] vs 417 [92] ml min(-1) m(-2), p = 0.0012) and the insulin/glucose incremental area ratio (an empirical index of beta cell function; 98 [74] vs 138 [122] pmol/mmol, p = 0.028) were reduced in women with pGDM.


CONCLUSIONS
Even in women who maintain normal insulin sensitivity, impaired beta cell function is carried over into the NGT status several years after a GDM pregnancy.
Seghieri
G
G
Division of Internal Medicine, Spedali Riuniti, Pistoia, Italy.
Tesi
F
F
Anichini
R
R
De Bellis
A
A
Barsotti
E
E
Mari
A
A
Ferrannini
E
E
D000328:Adult; D001786:Blood Glucose / Q000378:metabolism*; D015331:Cohort Studies; D003920:Diabetes Mellitus / Q000453:epidemiology; D016640:Diabetes, Gestational / Q000097:blood*; D005260:Female; D005500:Follow-Up Studies; D005951:Glucose Tolerance Test; D006801:Humans; D007333:Insulin Resistance; D050417:Insulin-Secreting Cells / Q000502:physiology; D007700:Kinetics; D011247:Pregnancy; D011263:Pregnancy Trimester, Third; D012016:Reference Values; D016896:Treatment Outcome
D001786:Blood Glucose