Influence of Ancestry in Adiposity Anthropometric Measures in Hispanics with Type 2 Diabetes

Program: Abstracts - Orals, Featured Poster Presentations, and Posters
Session: SUN 758-779-Cardiometabolic Risk & Vascular Biology
Clinical
Sunday, June 16, 2013: 1:45 PM-3:45 PM
Expo Halls ABC (Moscone Center)

Poster Board SUN-773
Liliana Uribe-Bruce*1, Ondrej Libiger2, Athena Philis-Tsimikas3, Maria I. Garcia4, Monica Ruiz4, Nathan E Wineinger5 and Nicholas J Schork6
1The Scripps Research Institute, Scripps Translational Science institute, San Diego, CA, 2The Scripps Research Institute, La Jolla, CA, 3Scripps Whittier Diabetes Inst, La Jolla, CA, 4Scripps Whittier Diabetes Institute, La Jolla, CA, 5Scripps Translational Science Institute, La Jolla, CA, 6Scripps Translational Science Institute, Scripps Health, Scripps Research Institute, La Jolla, CA
Aim of Investigation:  To explore the relationship between genetically-determined ancestry proportions and clinical adiposity measurements in an admixed Hispanic population with Type 2 Diabetes (T2D).

Background:  Body fat distribution is an important risk factor for T2D and cardiovascular disease. However, the clinical utility of proposed measures of body fat distribution, such as waist circumference (Wc) and waist-to-height ratio (WtHR), is complicated by the fact that their distributions vary among races and ethnic groups.(1,2) Establishing normative values that facilitate the use of these anthropometric clinical measures is particularly challenging in Hispanic populations due to their complex admixture patterns involving European, Amerindian and African ancestries.

Methods:  DNA samples from 238 Mexican-American males and females with T2D who were recruited to be participants in a Diabetes Genetic databank initiative in San Diego, CA, were genotyped with Illumina’s Metabochip.  We calculated the degree of Native American ancestry for each individual in the cohort using the genotype data and a panel of individuals whose ancestries were known and included several Native American individuals living in present day Mexico.(3) Regression analysis was pursued to assess the relationship between ancestry and Wc, WtHR, body mass index (BMI) and formal education (Ed), while controlling for covariates such as gender and age.

Results: We found a statistically significant negative correlation between the degree of Native American ancestry and Wc (p=0.00008), WtHR (p=0.002) and BMI (p=0.001), adjusted for age, gender, income and Ed.  We also observed a statistically significant correlation between Ed and Wc, WtHR and BMI (adjusted for age gender, degree of Native American ancestry and income). 

Conclusions:  Our results suggest that Native American ancestry in a population of Mexican Americans with T2D is associated with smaller Wc, WtHR and BMI. In addition, socioeconomic factors such as Ed need to be included in the analysis of adiposity distribution and obesity when studying diverse populations.  Given the genetic diversity and patterns of admixture across human groups now labeled as “Hispanics,” we suggest that genetic ancestry should be part of studies in these groups to determine the true normative clinical values of Wc and WtHR to facilitate the determination of cardiovascular and T2D risk.

(1) World Health Organization.  Waist circumference and Waist-Hip Ratio: Report of a WHO expert Consultation, 2011.  Accessed at whqlibdoc.who.int/publications/2011 on January 15, 2013.  (2) Gwynn R. Ch., et al. "Measures of Adiposity and Cardiovascular Disease Risk Factors, New York City Health and Nutrition Examination Survey 2004". Prev Chronic Dis 2011;8(3);A56.  (3) Libiger O, Schork NJ.  "A method for Inferring an Individual's Genetic Ancestry and Degree of Admixture Associated with Six Major Continental Populations".  Front Gene.  doi 10.3389/fgene.2012.00322

Disclosure: AP: Advisory Group Member, Novo Nordisk, Advisory Group Member, Sanofi, Advisory Group Member, Merck & Co., Research Funding, Takeda, Research Funding, Daiichi Sankyo, Research Funding, Merck & Co., Research Funding, Novo Nordisk, Research Funding, Sanofi, Research Funding, Eli Lilly & Company, Research Funding, Amylin Pharmaceuticals, Research Funding, Astra Zeneca, Research Funding, Pfizer, Inc.. NJS: Founder, Cypher Genomics,La Jolla, CA. Nothing to Disclose: LU, OL, MIG, MR, NEW

*Please take note of The Endocrine Society's News Embargo Policy at http://www.endo-society.org/endo2013/media.cfm

Sources of Research Support: NIH Grant 5KL2-RR025773-04