Article

Diabetologia

, Volume 55, Issue 5, pp 1329-1337

First online:

Relationship between diabetes risk and admixture in postmenopausal African-American and Hispanic-American women

  • L. QiAffiliated withDepartment of Public Health Sciences, University of California
  • , R. NassirAffiliated withDepartment of Biochemistry and Molecular Medicine, University of California, UC DavisDepartment of Internal Medicine, University of California
  • , R. KosoyAffiliated withDepartment of Biochemistry and Molecular Medicine, University of California, UC DavisDepartment of Internal Medicine, University of California
  • , L. GarciaAffiliated withDepartment of Public Health Sciences, University of California
  • , J. D. CurbAffiliated withDepartment of Geriatric and Internal Medicine, John A Burns School of Medicine, University of Hawaii, Manoa
  • , L. TinkerAffiliated withFred Hutchinson Cancer Research Center
  • , B. V. HowardAffiliated withMedStar Health Research InstituteGeorgetown and Howard Universities Center for Clinical and Translational Science
  • , J. RobbinsAffiliated withDepartment of Biochemistry and Molecular Medicine, University of California, UC DavisDepartment of Internal Medicine, University of California
  • , M. F. SeldinAffiliated withDepartment of Biochemistry and Molecular Medicine, University of California, UC DavisDepartment of Internal Medicine, University of California Email author 

Abstract

Aims/hypothesis

Type 2 diabetes is more prevalent in African-Americans (AFAs) and Hispanic-Americans (HAs) than in European-Americans. We assessed whether continental admixture was correlated with diabetes risk in these high-risk groups.

Methods

We estimated the proportion of sub-Saharan African (AFR), Amerindian (AMI) and European admixture using 92 ancestry-informative marker genotypes in 16,476 AFA and HA women from the Women’s Health Initiative. Cox regression models were used to examine the association between admixture and diabetes risk, with and without accounting for socioeconomic status (SES) and adiposity measurements.

Results

AFR admixture was significantly associated with diabetes risk in AFA women when adjusting for entry age, neighbourhood SES and BMI or waist/hip ratio (WHR) (all p < 0.0001). In HA women, AMI admixture had significant associations with diabetes risk that remained significant after adjustment for SES and BMI (all p < 0.0005). In both AFAs and HAs, SES showed significant negative associations while BMI or WHR had significant positive associations with diabetes risk, with and without adjustment for genetic admixture.

Conclusions/interpretation

In AFAs, admixture, SES and BMI/WHR each independently contribute to diabetes risk after accounting for each of the other factors; in HAs, admixture, SES and BMI each independently contribute to diabetes risk after accounting for each of the other factors, whereas admixture is not significantly associated with diabetes risk after accounting for SES and WHR. The findings emphasise the importance of considering both genetic and environmental causes in the aetiology of type 2 diabetes.

Keywords

Body mass index Diabetes Ethnicity Genetics Waist/hip circumference ratio