Correlation analysis of genetic admixture and social identification with body mass index in a Native American Community

Authors

  • Trina M. Norden-Krichmar,

    1. Scripps Translational Science Institute and The Department of Molecular and Experimental Medicine, The Scripps Research Institute, La Jolla, California
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  • Ian R. Gizer,

    1. Department of Psychological Sciences, University of Missouri, Columbia, Missouri
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  • Ondrej Libiger,

    1. Scripps Translational Science Institute and The Department of Molecular and Experimental Medicine, The Scripps Research Institute, La Jolla, California
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  • Kirk C. Wilhelmsen,

    1. Department of Genetics and Neurology, University of North Carolina, Chapel Hill, North Carolina
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  • Cindy L. Ehlers,

    Corresponding author
    1. Department of Molecular and Cellular Neuroscience, The Scripps Research Institute, La Jolla, California
    • Correspondence to: Nicholas J. Schork; J. Craig Venter Institute, La Jolla, CA 92037 USA. E-mail: nschork@jcvi.org and Cindy L. Ehlers; The Scripps Research Institute, La Jolla, CA 92037 USA, E-mail: cindye@scripps.edu

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  • Nicholas J. Schork

    Corresponding author
    1. Scripps Translational Science Institute and The Department of Molecular and Experimental Medicine, The Scripps Research Institute, La Jolla, California
    2. J. Craig Venter Institute, La Jolla, California
    • Correspondence to: Nicholas J. Schork; J. Craig Venter Institute, La Jolla, CA 92037 USA. E-mail: nschork@jcvi.org and Cindy L. Ehlers; The Scripps Research Institute, La Jolla, CA 92037 USA, E-mail: cindye@scripps.edu

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Abstract

Objectives

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. Am. J. Hum. Biol. 26:347–360, 2014. © 2014 Wiley Periodicals, Inc.

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