Characteristics of glucose metabolism in Nordic and South Asian subjects with type 2 diabetes

PLoS One. 2013 Dec 31;8(12):e83983. doi: 10.1371/journal.pone.0083983. eCollection 2013.

Abstract

Background: Insulin resistance and type 2 diabetes are more prevalent in people of South Asian ethnicity than in people of Western European origin. To investigate the source of these differences, we compared insulin sensitivity, insulin secretion, glucose and lipid metabolism in South Asian and Nordic subjects with type 2 diabetes.

Methods: Forty-three Nordic and 19 South Asian subjects with type 2 diabetes were examined with intra-venous glucose tolerance test, euglycemic clamp including measurement of endogenous glucose production, indirect calorimetry measuring glucose and lipid oxidation, and dual x-ray absorptiometry measuring body composition.

Results: Despite younger mean ± SD age (49.7 ± 9.4 vs 58.3 ± 8.3 years, p = 0.001), subjects of South Asian ethnicity had the same diabetes duration (9.3 ± 5.5 vs 9.6 ± 7.0 years, p = 0.86), significantly higher median [inter-quartile range] HbA1c (8.5 [1.6] vs 7.3 [1.6] %, p = 0.024) and lower BMI (28.7 ± 4.0 vs 33.2 ± 4.7 kg/m(2), p<0.001). The South Asian group exhibited significantly higher basal endogenous glucose production (19.1 [9.1] vs 14.4 [6.8] µmol/kgFFM · min, p = 0.003). There were no significant differences between the groups in total glucose disposal (39.1 ± 20.4 vs 39.2 ± 17.6 µmol/kgFFM · min, p = 0.99) or first phase insulin secretion (AUC0-8 min: 220 [302] vs 124 [275] pM, p = 0.35). In South Asian subjects there was a tendency towards positive correlations between endogenous glucose production and resting and clamp energy expenditure.

Conclusions: Subjects of South Asian ethnicity with type 2 diabetes, despite being younger and leaner, had higher basal endogenous glucose production, indicating higher hepatic insulin resistance, and a trend towards higher use of carbohydrates as fasting energy substrate compared to Nordic subjects. These findings may contribute to the understanding of the observed differences in prevalence of type 2 diabetes between the ethnic groups.

Publication types

  • Comparative Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Absorptiometry, Photon
  • Adult
  • Asia / ethnology
  • Calorimetry, Indirect
  • Diabetes Mellitus, Type 2 / ethnology*
  • Diabetes Mellitus, Type 2 / metabolism
  • Energy Metabolism
  • Europe / ethnology
  • Female
  • Glucose / metabolism*
  • Glucose Clamp Technique
  • Glucose Tolerance Test
  • Glycated Hemoglobin A / metabolism
  • Humans
  • Insulin / metabolism
  • Insulin Resistance*
  • Liver / metabolism*
  • Male
  • Middle Aged
  • Vitamin D / analysis

Substances

  • Glycated Hemoglobin A
  • Insulin
  • Vitamin D
  • Glucose

Grant support

The study was funded with grants from the South Eastern Norway Regional Health Authority, the EXTRA Foundation, The Norwegian Diabetes Association, and Freia Chokolade Fabrik’s Medical Foundation. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.