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Cheng CY, Reich D, Haiman CA, Tandon A, Patterson N, Elizabeth S, Akylbekova EL, Brancati FL, Coresh J, Boerwinkle E, Altshuler D, Taylor HA, Henderson BE, Wilson JG, Kao WHL. African ancestry and its correlation to type 2 diabetes in African Americans: a genetic admixture analysis in three U.S. population cohorts. PLoS One 2012; 7:e32840. [PMID: 22438884 PMCID: PMC3306373 DOI: 10.1371/journal.pone.0032840] [Citation(s) in RCA: 58] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2011] [Accepted: 01/31/2012] [Indexed: 11/18/2022] Open
Abstract
The risk of type 2 diabetes is approximately 2-fold higher in African Americans than in European Americans even after adjusting for known environmental risk factors, including socioeconomic status (SES), suggesting that genetic factors may explain some of this population difference in disease risk. However, relatively few genetic studies have examined this hypothesis in a large sample of African Americans with and without diabetes. Therefore, we performed an admixture analysis using 2,189 ancestry-informative markers in 7,021 African Americans (2,373 with type 2 diabetes and 4,648 without) from the Atherosclerosis Risk in Communities Study, the Jackson Heart Study, and the Multiethnic Cohort to 1) determine the association of type 2 diabetes and its related quantitative traits with African ancestry controlling for measures of SES and 2) identify genetic loci for type 2 diabetes through a genome-wide admixture mapping scan. The median percentage of African ancestry of diabetic participants was slightly greater than that of non-diabetic participants (study-adjusted difference = 1.6%, P<0.001). The odds ratio for diabetes comparing participants in the highest vs. lowest tertile of African ancestry was 1.33 (95% confidence interval 1.13–1.55), after adjustment for age, sex, study, body mass index (BMI), and SES. Admixture scans identified two potential loci for diabetes at 12p13.31 (LOD = 4.0) and 13q14.3 (Z score = 4.5, P = 6.6×10−6). In conclusion, genetic ancestry has a significant association with type 2 diabetes above and beyond its association with non-genetic risk factors for type 2 diabetes in African Americans, but no single gene with a major effect is sufficient to explain a large portion of the observed population difference in risk of diabetes. There undoubtedly is a complex interplay among specific genetic loci and non-genetic factors, which may both be associated with overall admixture, leading to the observed ethnic differences in diabetes risk.
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Affiliation(s)
- Ching-Yu Cheng
- Department of Epidemiology, Johns Hopkins University, Baltimore, Maryland, United States of America
- Saw Swee Hock School of Public Health, and Department of Ophthalmology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore
- Duke-NUS Graduate Medical School, Singapore, Singapore
- Singapore Eye Research Institute, Singapore, Singapore
| | - David Reich
- Department of Genetics, Harvard Medical School, Boston, Massachusetts, United States of America
- Program in Medical and Population Genetics, Broad Institute of Harvard and M.I.T., Cambridge, Massachusetts, United States of America
| | - Christopher A. Haiman
- Department of Preventive Medicine, Keck School of Medicine, University of Southern California, Los Angeles, California, United States of America
| | - Arti Tandon
- Department of Genetics, Harvard Medical School, Boston, Massachusetts, United States of America
- Program in Medical and Population Genetics, Broad Institute of Harvard and M.I.T., Cambridge, Massachusetts, United States of America
| | - Nick Patterson
- Program in Medical and Population Genetics, Broad Institute of Harvard and M.I.T., Cambridge, Massachusetts, United States of America
| | - Selvin Elizabeth
- Department of Epidemiology, Johns Hopkins University, Baltimore, Maryland, United States of America
- Welch Center for Prevention, Epidemiology and Clinical Research, Johns Hopkins University, Baltimore, Maryland, United States of America
| | - Ermeg L. Akylbekova
- Jackson Heart Study Analysis Group, Jackson State University, Jackson, Mississippi, United States of America
| | - Frederick L. Brancati
- Department of Epidemiology, Johns Hopkins University, Baltimore, Maryland, United States of America
- Welch Center for Prevention, Epidemiology and Clinical Research, Johns Hopkins University, Baltimore, Maryland, United States of America
- Department of Medicine, Johns Hopkins University, Baltimore, Maryland, United States of America
| | - Josef Coresh
- Department of Epidemiology, Johns Hopkins University, Baltimore, Maryland, United States of America
- Welch Center for Prevention, Epidemiology and Clinical Research, Johns Hopkins University, Baltimore, Maryland, United States of America
| | - Eric Boerwinkle
- Human Genetics Center, University of Texas Health Science Center at Houston, Houston, Texas, United States of America
| | - David Altshuler
- Department of Medicine, Harvard Medical School, Boston, Massachusetts, United States of America
- Program in Medical and Population Genetics, Broad Institute of Harvard and M.I.T., Cambridge, Massachusetts, United States of America
- Center for Human Genetic Research and Diabetes Unit, Department of Medicine, Massachusetts General Hospital, Boston, Massachusetts, United States of America
| | - Herman A. Taylor
- Jackson State University, Tougaloo College, and the University of Mississippi Medical Center, Jackson, Mississippi, United States of America
| | - Brian E. Henderson
- Department of Preventive Medicine, Keck School of Medicine, University of Southern California, Los Angeles, California, United States of America
| | - James G. Wilson
- Department of Physiology and Biophysics, The University of Mississippi Medical Center, Jackson, Mississippi, United States of America
| | - W. H. Linda Kao
- Department of Epidemiology, Johns Hopkins University, Baltimore, Maryland, United States of America
- Department of Medicine, Johns Hopkins University, Baltimore, Maryland, United States of America
- * E-mail:
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Joshu CE, Elizabeth S, Prizment AE, Dluzniewski PJ, Menke A, Folsom AR, Coresh J, Yeh HC, Brancati FL, Platz EA. Abstract A74: Glycated hemoglobin and cancer incidence and mortality in the Atherosclerosis in Communities (ARIC) Study, 1990–2006. Cancer Prev Res (Phila) 2011. [DOI: 10.1158/1940-6207.prev-11-a74] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Abstract
Background: Diabetes is a risk factor for many cancers; chronic hyperglycemia is hypothesized to be, in part, explanatory. We evaluated the association between glycated hemoglobin, a time-integrated glycemia measure, and cancer incidence and mortality in non-diabetic and diabetic men and women.
Methods: We conducted a prospective study of 12,792 cancer-free participants attending the second visit (1990–1992) of the Atherosclerosis Risk in Communities (ARIC) Study. We measured glycated hemoglobin in whole-blood samples using HPLC. Incident cancers were ascertained from registries and hospital records through 2006. We estimated multivariable-adjusted hazard ratios (HR) of cancer incidence and mortality for non-diabetic participants with values ≥5.7% (elevated), non-diabetic participants with <5.0% (low), and diabetic participants all compared with non-diabetic participants with 5.0–5.6% (normal).
Results: We ascertained 2,349 incident cancer cases and 887 cancer deaths. Compared with non-diabetic women with normal glycated hemoglobin, non-diabetic women with elevated values had an increased risk of cancer incidence (HR:1.24; 95% CI:1.07,1.44) and mortality (HR:1.58; 95% CI:1.23,2.05) as did diabetic women (incidence, HR:1.30; 95% CI:1.06,1.60, mortality, HR:1.96; 95% CI:1.40,2.76). Non-diabetic women with low values also had increased risk. Diabetic women with good glycemic control (<7.0%) had a lower cancer risk than those with higher values. Glycated hemoglobin in non-diabetic and diabetic men, and diabetes were not associated with risk.
Conclusions: Our findings support the hypothesis that chronic hyperglycemia, even in the non-diabetic range, increases cancer risk in women, but not men. Maintaining normal glycated hemoglobin overall, and good glycemic control among diabetic adults, may reduce the burden of cancer.
Citation Information: Cancer Prev Res 2011;4(10 Suppl):A74.
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Affiliation(s)
| | | | | | | | - Andy Menke
- 1Johns Hopkins University, Baltimore, MD
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