The authors state that they have no conflicts of interest.
Heritability of BMD of Femoral Neck and Lumbar Spine: A Multivariate Twin Study of Finnish Men†
Article first published online: 4 JUN 2007
Copyright © 2007 ASBMR
Journal of Bone and Mineral Research
Volume 22, Issue 9, pages 1455–1462, September 2007
How to Cite
Videman, T., Levälahti, E., Battié, M. C., Simonen, R., Vanninen, E. and Kaprio, J. (2007), Heritability of BMD of Femoral Neck and Lumbar Spine: A Multivariate Twin Study of Finnish Men. J Bone Miner Res, 22: 1455–1462. doi: 10.1359/jbmr.070606
- Issue published online: 4 DEC 2009
- Article first published online: 4 JUN 2007
- Manuscript Accepted: 31 MAY 2007
- Manuscript Revised: 9 MAY 2007
- Manuscript Received: 15 NOV 2006
- genetic research;
- mechanical loading;
Of the 80% variation in BMD among male twins that is caused by genetics, part was explained by genetic influences on lifting strength and lean body mass/height. Lifting strength was significant in both the femoral and spine BMD and body weight only for lumbar BMD.
Introduction: The dominant role of heritability in BMD has been shown in twin studies among women. However, the mechanisms of genetic influences are poorly understood. BMD is associated with lean body mass and muscle strength, which both have a genetic component, but the relative effects of muscle strength and lean body mass/height on the total genetic and environmental variations influencing BMD of men are unclear.
Materials and Methods: Measurements of BMD from a DXA scanner on a representative sample of 147 monozygotic and 153 dizygotic male twin pairs (age, 35–70 yr) were related to a variety of anthropometric and behavioral covariates and interview data. Data were analyzed with univariate modeling of genetic characteristics, bivariate modeling of covariates that were significant in univariate models, and multivariate modeling of the simultaneous effects of significant covariates from the bivariate models.
Results: Heritability influences were estimated to account for 75% of the variance in femoral BMD and 83% in lumbar BMD. Univariate and bivariate modeling showed that, of the factors studied, only lifting force and lean body mass/height had statistically significant influences. Of the total genetic variation in femoral BMD, lifting force explained 9%, and lean body mass/height 18%; the proportions for lumbar BMD were 9% and 11%, respectively. Of the total environmental variation, the correlation with isokinetic lifting force explained 9% for femoral BMD and 10% for lumbar BMD. The genetic correlations between lifting force and femoral and lumbar BMD were ∼0.3, as were the environmental correlations of isokinetic lifting force and femoral and lumbar BMD and of lean body mass/height and femoral BMD. The environmental correlation of lean body mass/height and femoral BMD was not significant.
Conclusions: Lifting force had effects on both femoral and lumbar BMD. Body weight was important, but only for lumbar BMD. Muscle strength may have the best potential for modification among behavioral factors to increase both femoral and lumbar BMD.