Correlation analysis of genetic admixture and social identification with body mass index in a Native American community.
OBJECTIVE
Body mass index (BMI) is a well-known measure of obesity with a multitude of genetic and non-genetic determinants. Identifying the underlying factors associated with BMI is difficult because of its multifactorial etiology that varies as a function of geoethnic background and socioeconomic setting. Thus, we pursued a study exploring the influence of the degree of Native American admixture on BMI (as well as weight and height individually) in a community sample of Native Americans (n = 846) while accommodating a variety of socioeconomic and cultural factors.


METHODS
Participants' degree of Native American (NA) ancestry was estimated using a genome-wide panel of markers. The participants also completed an extensive survey of cultural and social identity measures: the Indian Culture Scale (ICS) and the Orthogonal Cultural Identification Scale (OCIS). Multiple linear regression was used to examine the relation between these measures and BMI.


RESULTS
Our results suggest that BMI is correlated positively with the proportion of NA ancestry. Age was also significantly associated with BMI, while gender and socioeconomic measures (education and income) were not. For the two cultural identity measures, the ICS showed a positive correlation with BMI, while OCIS was not associated with BMI.


CONCLUSIONS
Taken together, these results suggest that genetic and cultural environmental factors, rather than socioeconomic factors, account for a substantial proportion of variation in BMI in this population. Further, significant correlations between degree of NA ancestry and BMI suggest that admixture mapping may be appropriate to identify loci associated with BMI in this population.
Scripps Translational Science Institute and The Department of Molecular and Experimental Medicine, The Scripps Research Institute, La Jolla, California, 92037.
Trina M
TM
Norden-Krichmar
Ian R
IR
Gizer
Ondrej
O
Libiger
Kirk C
KC
Wilhelmsen
Cindy L
CL
Ehlers
Nicholas J
NJ
Schork
D000293:Adolescent; D000328:Adult; D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D001827:Body Height; D015992:Body Mass Index; D001835:Body Weight; D005260:Female; D005819:Genetic Markers; D055106:Genome-Wide Association Study; D006801:Humans; D007198:Indians, North American; D008297:Male; D008875:Middle Aged; D009656:North America; D010375:Pedigree; D012044:Regression Analysis; D012933:Social Identification; D012959:Socioeconomic Factors; D055815:Young Adult
D005819:Genetic Markers