Relationship between diabetes risk and admixture in postmenopausal African-American and Hispanic-American women.
OBJECTIVE
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
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.
Department of Public Health Sciences, University of California, Davis, CA, USA.
L
L
Qi
R
R
Nassir
R
R
Kosoy
L
L
Garcia
J D
JD
Curb
L
L
Tinker
B V
BV
Howard
J
J
Robbins
M F
MF
Seldin
D050154:Adiposity / Q000235:genetics; D000368:Aged; D044383:Black People / Q000235:genetics / Q000706:statistics & numerical data*; D003924:Diabetes Mellitus, Type 2 / Q000208:ethnology* / Q000235:genetics; D005260:Female; D006630:Hispanic or Latino / Q000235:genetics / Q000706:statistics & numerical data*; D006801:Humans; D008875:Middle Aged; D017698:Postmenopause; D012306:Risk; D012923:Social Class; D044465:White People / Q000235:genetics / Q000706:statistics & numerical data; D001741:Black or African American