Total and high molecular weight adiponectin and ethnic-specific differences in adiposity and insulin resistance: a cross-sectional study.
BACKGROUND
Ethnic-specific differences in insulin resistance (IR) are well described but the underlying mechanisms are unknown. Adiponectin is an insulin sensitizing adipocytokine that circulates as multiple isoforms, with high molecular weight (HMW) adiponectin associated with greatest insulin sensitivity. The objective of this study is to determine if plasma total and HMW adiponectin concentrations underlie ethnic-specific differences in IR.


METHODS
Healthy Canadian Aboriginal, Chinese, European, and South Asian adults (N = 634) were assessed for sociodemographics; lifestyle; fasting plasma insulin, glucose, and total and HMW adiponectin; and adiposity measures [BMI, waist circumference, waist-to-hip ratio, percent body fat, and subcutaneous and visceral adipose tissue (quantified by computed tomography)]. The homeostasis model assessment-insulin resistance (HOMA-IR) assessed IR.


RESULTS
South Asians had the greatest HOMA-IR, followed by Aboriginals, Chinese, and Europeans (P < 0.001). Plasma total and HMW adiponectin concentrations were lower in Chinese and South Asians than Aboriginal and Europeans (P < 0.05). Total and HMW adiponectin were inversely associated with HOMA-IR (P < 0.001). Ethnicity modified the relationship between HMW adiponectin and HOMA-IR with stronger effects observed in Aboriginals (P = 0.001), Chinese (P = 0.002), and South Asians (P = 0.040) compared to Europeans. This was not observed for total adiponectin (P = 0.431). At mean total adiponectin concentrations South Asians had higher HOMA-IR than Europeans (P < 0.001).


CONCLUSIONS
For each given decrease in HMW adiponectin concentrations a greater increase in HOMA-IR is observed in Aboriginals, Chinese, and South Asians than Europeans. Ethnic-specific differences in HMW adiponectin may account for differences in IR.
Department of Pediatrics, University of British Columbia, Child and Family Research Institute, 272-950 West 28th Avenue, Vancouver, V5Z 4H4, Canada. adevlin@cfri.ubc.ca.
Dian C
DC
Sulistyoningrum
Danijela
D
Gasevic
Scott A
SA
Lear
Joe
J
Ho
Andrew
A
Mente
Angela M
AM
Devlin
D052242:Adiponectin / Q000097:blood*; D050154:Adiposity / Q000208:ethnology*; D000328:Adult; D044467:American Indian or Alaska Native / Q000706:statistics & numerical data; D044466:Asian People / Q000706:statistics & numerical data; D015415:Biomarkers / Q000097:blood; D015992:Body Mass Index; D002170:Canada / Q000453:epidemiology; D002681:China / Q000208:ethnology; D003430:Cross-Sectional Studies; D005006:Ethnicity / Q000706:statistics & numerical data*; D005260:Female; D006801:Humans; D007333:Insulin Resistance / Q000208:ethnology*; D050152:Intra-Abdominal Fat / Q000000981:diagnostic imaging; D008297:Male; D008875:Middle Aged; D012307:Risk Factors; D050151:Subcutaneous Fat / Q000000981:diagnostic imaging; D014057:Tomography, X-Ray Computed; D055105:Waist Circumference; D049629:Waist-Hip Ratio; D044465:White People / Q000706:statistics & numerical data
C499918:ADIPOQ protein, human; D052242:Adiponectin; D015415:Biomarkers