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Acta Diabetologica

, Volume 51, Issue 1, pp 53–60 | Cite as

Insulin resistance and beta-cell function in different ethnic groups in Kenya: the role of abdominal fat distribution

  • D. L. Christensen
  • D. Faurholt-Jepsen
  • K. Faerch
  • D. L. Mwaniki
  • M. K. Boit
  • B. Kilonzo
  • I. Tetens
  • H. Friis
  • K. Borch-Johnsen
Original Article

Abstract

Little is known about the pathophysiology of diabetes in Africans. Thus, we assessed whether insulin resistance and beta-cell function differed by ethnicity in Kenya and whether differences were modified by abdominal fat distribution. A cross-sectional study in 1,087 rural Luo (n = 361), Kamba (n = 378), and Maasai (n = 348) was conducted. All participants had a standard 75-g oral glucose tolerance test (OGTT). Venous blood samples were collected at 0, 30, and 120 min. Serum insulin was analysed at 0 and 30 min. From the OGTT, we assessed the homoeostasis model assessment of insulin resistance by computer model, early phase insulin secretion, and disposition index (DI) dividing insulin secretion by insulin resistance. Abdominal subcutaneous adipose tissue (SAT) and visceral adipose tissue (VAT) thickness were carried out by ultrasonography. Linear regression analyses were done to assess ethnic differences in insulin indices. The Maasai had 32 and 17 % higher insulin resistance than the Luo and Kamba, respectively (p < 0.001). Early phase insulin secretion was 16 % higher in the Maasai compared to the Luo (p < 0.001). DI was 12 % (p = 0.002) and 10 % (p = 0.015) lower in the Maasai compared to the Luo and Kamba, respectively. Adjustments of SAT (range 0.1–7.1 cm) and VAT (range 1.5–14.2 cm) largely explained these inter-group differences with the Maasai having the highest combined abdominal fat accumulation. The Maasai had the highest insulin resistance and secretion, but the lowest relative beta-cell function compared to the Luo and Kamba. These differences were primarily explained by abdominal fat distribution.

Keywords

Insulin resistance Insulin secretion Ethnicity Obesity 

Abbreviations

DI

Disposition index

HOMA2-IR

Homoeostasis model assessment of insulin resistance by computer model

IFG

Impaired fasting glucose

IGT

Impaired glucose tolerance

OGTT

Oral glucose tolerance test

SAT

Abdominal subcutaneous adipose tissue

VAT

Visceral adipose tissue

Notes

Acknowledgments

We are grateful to all participants, the local chiefs and sub-chiefs, the local elder councils and district politicians. We are also indebted to the late Benedict Omondi (KEMRI), Tobias Oketch (CVBCR), Arthur J Ukumu (DVBD), Odero Sabiano (DVBD), and Saidi Kisiwa (KEMRI) for their skilful collection and analysis of blood samples in the field. Likewise, we sincerely thank all local assistants for their effort in excellent social mobilization and collection of data. We acknowledge the permission by the Director of KEMRI to publish this manuscript. The study was supported by DANIDA, Cluster of International Health (University of Copenhagen), Steno Diabetes Center, Beckett Foundation, Dagmar Marshall Foundation, Dr. Thorvald Madsen’s Grant, Kong Christian den Tiende’s Foundation, Brdr. Hartmann Foundation. The funding bodies had no role in the study design, data collection, data analysis, data interpretation or decision to publish the findings.

Conflict of interest

The authors declare no conflict of interest.

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Copyright information

© Springer-Verlag Italia 2013

Authors and Affiliations

  • D. L. Christensen
    • 1
    • 2
  • D. Faurholt-Jepsen
    • 3
  • K. Faerch
    • 2
  • D. L. Mwaniki
    • 4
    • 5
  • M. K. Boit
    • 6
  • B. Kilonzo
    • 4
  • I. Tetens
    • 7
  • H. Friis
    • 3
  • K. Borch-Johnsen
    • 8
  1. 1.Department of International Health, Immunology, and MicrobiologyUniversity of CopenhagenCopenhagenDenmark
  2. 2.Steno Diabetes CenterGentofteDenmark
  3. 3.University of CopenhagenFrederiksbergDenmark
  4. 4.KEMRINairobiKenya
  5. 5.Family Health InternationalNairobiKenya
  6. 6.Kenyatta UniversityNairobiKenya
  7. 7.Technical University of DenmarkSøborgDenmark
  8. 8.Holbæk SygehusHolbækDenmark

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