Is There Overlap Between the Genetic Determinants of Mammographic Density and Bone Mineral Density?
- Gillian S. Dite1,
- John D. Wark2,
- Graham G. Giles1,3,
- Dallas R. English1,3,
- Margaret R.E. McCredie4 and
- John L. Hopper1
- 1Centre for Molecular, Environmental, Genetic, and Analytic Epidemiology, The University of Melbourne, Australia, 2Department of Medicine, The University of Melbourne, Royal Melbourne Hospital, Australia, 3Cancer Epidemiology Centre, Cancer Council Victoria, Melbourne, Australia; and 4Department of Preventive and Social Medicine, University of Otago, New Zealand
- Requests for reprints:
John L. Hopper, Centre for Molecular, Environmental, Genetic and Analytic Epidemiology, The University of Melbourne, Level 2/723 Swanston Street, Carlton, VIC 3053, Australia. Phone: 61-3-8344-0697; Fax: 61-3-9349-5815. E-mail: j.hopper{at}unimelb.edu.au
Abstract
Mammographic density and bone mineral density, risk factors for breast cancer and osteoporotic fractures, respectively, are both thought to reflect cumulative exposure to estrogen and are highly heritable. We asked if there was overlap between the genes that explain their variances. We studied 63 monozygous and 71 dizygous female twin pairs ages 38 to 71 years (mean, 50 years). Absolute and percent mammographic densities were measured by a computer-assisted method, and bone mineral density was measured at the lumbar spine, femoral neck, and forearm by dual energy X-ray absorptiometry. After adjusting for age, height, and weight, the within-person and cross-trait cross-twin correlations between the mammographic density and bone mineral density measures were between −0.09 and 0.16 (SEs, 0.07-0.09) and independent of zygosity (all P > 0.05). We conclude that there is little, if any, overlap between the genetic or environmental determinants of disease risk associated with these traits.
Footnotes
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Grant support: The mammographic density study was supported by the Kathleen Cuningham Foundation (now the National Breast Cancer Foundation) the Victorian Breast Cancer Research Consortium and the Merck Sharp and Dohme Research Foundation. The bone mineral density study was supported by the National Health and Medical Research Council, the Victorian Health Promotion Foundation, and the Helen M. Schutt Trust.
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The costs of publication of this article were defrayed in part by the payment of page charges. This article must therefore be hereby marked advertisement in accordance with 18 U.S.C. Section 1734 solely to indicate this fact.
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- Accepted July 19, 2005.
- Received April 20, 2005.
- Revision received July 8, 2005.
