Ethnic Differences in the Role of Adipocytokines Linking Abdominal Adiposity and Insulin Sensitivity Among Asians

Parvaresh Rizi E 1 , Teo Y 1 , Leow MK 1 , Venkataraman K , Khoo EY 1 , Yeo CR 1 Show all authors , Chan E 1 , Song T 1 , Sadananthan SA 1 , Velan SS 1 , Gluckman PD 1 , Lee YS 1 , Chong YS 1 , Tai ES 1 , Toh SA 1 , Khoo CM 1

Affiliations 

  • 1 Department of Medicine (E.P.R., Y.T., E.Y.H.K., C.R.Y., E.C., T.S., E.S.T., S.-A.T., C.M.K.), Yong Loo Lin School of Medicine, National University of Singapore, Singapore 117597; Department of Medicine (E.P.R., E.Y.H.K., E.S.T., S.-A.T., C.M.K.), National University Health System, Singapore 119228; Duke-National University of Singapore Graduate Medical School (E.S.T., S.-A.T., C.M.K.), Singapore 169857; Department of Endocrinology (M.K.-S.L.), Tan Tock Seng Hospital, Singapore 308433; Singapore Institute for Clinical Sciences (A*STAR) (M.K.-S.L., S.A.S., S.S.V., P.D.G., Y.S.L.), Brenner Centre for Molecular Medicine, Singapore 117609; Department of Obstetrics & Gynaecology (S.A.S., Y.S.C.), National University of Singapore, Singapore 119077; Singapore Bioimaging Consortium (S.S.V.), A*STAR, Singapore 138667; Clinical Imaging Research Centre (S.S.V.), A*STAR-NUS, Singapore 119077; and Department of Paediatrics (Y.S.L.), Yong Loo Lin School of Medicine, National University of Singapore, Singapore 117597
J Clin Endocrinol Metab, 2015 11;100(11):4249-56.
PMID: 26308293 DOI: 10.1210/jc.2015-2639

Abstract

CONTEXT: Among Asian ethnic groups, Chinese or Malays are more insulin sensitive than South Asians, in particular in lean individuals. We have further reported that body fat partitioning did not explain this ethnic difference in insulin sensitivity.

OBJECTIVE: We examined whether adipocytokines might explain the ethnic differences in the relationship between obesity and insulin resistance among the three major ethnic groups in Singapore.

DESIGN AND PARTICIPANTS: This was a cross-sectional study of 101 Chinese, 82 Malays, and 81 South Asian men. Insulin sensitivity index (ISI) was measured using hyperinsulinemic euglycemic clamp. Visceral (VAT) and subcutaneous adipose tissue (SAT) volumes were quantified using magnetic resonance imaging.

MAIN OUTCOME MEASURES: Plasma total and high-molecular-weight adiponectin, leptin, visfatin, apelin, IL-6, fibroblast growth factor 21 (FGF21), retinol binding protein-4 (RBP 4), and resistin were measured using enzyme-linked immunoassays.

RESULTS: Principle component (PC) analysis on the adipocytokines identified three PCs, which explained 49.5% of the total variance. Adiponectin loaded negatively, and leptin and FGF21 loaded positively onto PC1. Visfatin, resistin, and apelin all loaded positively onto PC2. IL-6 loaded positively and RBP-4 negatively onto PC3. Only PC1 was negatively associated with ISI in all ethnic groups. In the path analysis, SAT and VAT were negatively associated with ISI in Chinese and Malays without significant mediatory role of PC1. In South Asians, the relationship between VAT and ISI was mediated partly through PC1, whereas the relationship between SAT and ISI was mediated mainly through PC1.

CONCLUSIONS: The relationships between abdominal obesity, adipocytokines and insulin sensitivity differ between ethnic groups. Adiponectin, leptin, and FGF21 play a mediating role in the relationship between abdominal adiposity and insulin resistance in South Asians, but not in Malays or Chinese.

* Title and MeSH Headings from MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

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