This Article Full Text Full Text (PDF) All Versions of this Article: 91/1/93    most recent Author Manuscript (PDF) Submit a related Letter to the Editor Purchase Article View Shopping Cart Alert me when this article is cited Alert me when eLetters are posted Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Request Copyright Permission Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Retnakaran, R. Articles by Zinman, B. Search for Related Content PubMed PubMed Citation Articles by Retnakaran, R. Articles by Zinman, B. Related Collections Diabetes and Insulin Female Endocrinology Metabolism

Ethnicity Modifies the Effect of Obesity on Insulin Resistance in Pregnancy: A Comparison of Asian, South Asian, and Caucasian Women

Division of Endocrinology (R.R., A.J.G.H., B.Z.) and Department of Laboratory Medicine and Pathobiology (P.W.C.), University of Toronto, Toronto, Ontario, Canada M5G 1L5; and Leadership Sinai Centre for Diabetes (R.R., A.J.G.H., B.Z.) and Division of Obstetrics and Gynecology (M.S.), Mount Sinai Hospital, Toronto, Ontario, Canada M5G 1X5

Address all correspondence and requests for reprints to: Dr. Bernard Zinman, Leadership Sinai Centre for Diabetes, Mount Sinai Hospital, Lebovic Building, Room L5-024, 600 University Avenue, Toronto, Ontario, Canada M5G 1X5. E-mail: zinman{at}mshri.on.ca

Context: Women of Asian and South Asian descent are at increased risk of developing gestational diabetes mellitus compared with Caucasians, despite lower body mass index (BMI). Nevertheless, there has been limited study of insulin action during pregnancy in these ethnic groups.

Objective: The objective of the study was to compare insulin sensitivity in pregnancy in Asian, South Asian, and Caucasian subjects and to determine whether the impact of obesity on insulin action is modified by ethnicity.

Design and Participants: A cross-sectional study was performed in outpatients undergoing oral glucose tolerance testing in late pregnancy. Participants were stratified into three groups: 1) Caucasian (n = 116); 2) South Asian (n = 31); and 3) Asian (n = 28).

Main Outcome Measure: Insulin sensitivity was measured using the oral glucose tolerance test (IS_OGTT) index of M. Matsuda and R. DeFronzo, previously validated in pregnancy.

Results: There were no significant ethnic differences in insulin sensitivity despite variation in prepregnancy BMI (Caucasians, 25.2 kg/m²; South Asians, 23.3 kg/m²; Asians, 21.4 kg/m²; overall P = 0.0001). On multiple linear regression analysis, the strongest independent determinants of IS_OGTT were gestational diabetes mellitus (t = –5.71; P < 0.0001) and BMI (t = –5.43; P < 0.0001). Importantly, both Asian (t = –2.87; P = 0.0047) and South Asian (t = –2.46; P = 0.015) ethnicity also emerged as negative, independent determinants of IS_OGTT. Furthermore, Asian ethnicity significantly modified the association of prepregnancy BMI with IS_OGTT (interaction term, t = –2.29; P = 0.0231)

Conclusions: Asian and South Asian ethnicity are both independently associated with increased insulin resistance in late pregnancy. Prepregnancy BMI has a much greater effect on insulin resistance in pregnancy in Asian women than in Caucasians. Ethnicity thus emerges as a factor that modulates the effect of obesity on insulin resistance in pregnancy.

This article has been cited by other articles:

				T. M. Wolever, J. C Brand-Miller, J. Abernethy, A. Astrup, F. Atkinson, M. Axelsen, I. Bjorck, F. Brighenti, R. Brown, A. Brynes, et al. Measuring the glycemic index of foods: interlaboratory study Am. J. Clinical Nutrition, January 1, 2008; 87(1): 247S - 257S. [Abstract] [Full Text] [PDF]

				R. Retnakaran, A. J.G. Hanley, and B. Zinman Does Hypoadiponectinemia Explain the Increased Risk of Diabetes and Cardiovascular Disease in South Asians? Diabetes Care, August 1, 2006; 29(8): 1950 - 1954. [Full Text] [PDF]