Failure to increase insulin secretory capacity during pregnancy-induced insulin resistance is associated with ethnicity and gestational diabetes.
OBJECTIVE
To assess changes in insulin resistance and β-cell function in a multiethnic cohort of women in Oslo, Norway, from early to 28 weeks' gestation and 3 months post partum and relate the findings to gestational diabetes mellitus (GDM).


METHODS
Population-based cohort study of 695 healthy pregnant women from Western Europe (41%), South Asia (25%), Middle East (15%), East Asia (6%) and elsewhere (13%). Blood samples and demographics were recorded at mean 15 (V1) and 28 (V2) weeks' gestation and 3 months post partum (V3). Universal screening was by 75 g oral glucose tolerance test at V2, GDM with modified IADPSG criteria (no 1-h measurement): fasting plasma glucose (PG) ≥5.1 or 2-h PG ≥8.5 mmol/l. Homeostatic model assessment (HOMA)-β (β-cell function) and HOMA-IR (insulin resistance) were calculated from fasting glucose and C-peptide.


RESULTS
Characteristics were comparable across ethnic groups, except age (South Asians: younger, P<0.001) and prepregnant BMI (East Asians: lower, P=0.040). East and South Asians were more insulin resistant than Western Europeans at V1. From V1 to V2, the increase in insulin resistance was similar across the ethnic groups, but the increase in β-cell function was significantly lower for the East and South Asians compared with Western Europeans. GDM women compared with non-GDM women were more insulin resistant at V1; from V1 to V2, their β-cell function increased significantly less and the percentage increase in β-cell function did not match the change in insulin resistance.


CONCLUSIONS
Pregnant women from East Asia and South Asia were more insulin resistant and showed poorer HOMA-β-cell function than Western Europeans.
Department of Endocrinology, Obesity and Preventive Medicine, Oslo University Hospital HF, PO Box 4959 Nydalen, 0424 Oslo, Norway. kjersti.morkrid@medisin.uio.no
Kjersti
K
Mørkrid
Anne K
AK
Jenum
Line
L
Sletner
Mari H
MH
Vårdal
Christin W
CW
Waage
Britt
B
Nakstad
Siri
S
Vangen
Kåre I
KI
Birkeland
D000328:Adult; D015331:Cohort Studies; D016640:Diabetes, Gestational / Q000097:blood / Q000453:epidemiology / Q000208:ethnology / Q000378:metabolism*; D005006:Ethnicity / Q000706:statistics & numerical data; D005260:Female; D005500:Follow-Up Studies; D005843:Geography; D006801:Humans; D007328:Insulin / Q000097:blood / Q000378:metabolism*; D007333:Insulin Resistance / Q000208:ethnology / Q000502:physiology; D000078790:Insulin Secretion; D049590:Postpartum Period / Q000097:blood / Q000208:ethnology / Q000378:metabolism; D011247:Pregnancy / Q000097:blood / Q000208:ethnology* / Q000378:metabolism* / Q000706:statistics & numerical data; D011262:Pregnancy Trimester, Second / Q000097:blood / Q000208:ethnology / Q000378:metabolism; D011263:Pregnancy Trimester, Third / Q000097:blood / Q000208:ethnology / Q000378:metabolism; D055815:Young Adult
D007328:Insulin