uu.seUppsala University Publications
Change search
ReferencesLink to record
Permanent link

Direct link
Genetic influence on bone phenotypes and body composition: A Swedish twin study
Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Surgical Sciences, Orthopaedics.
Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Surgical Sciences, Orthopaedics.
Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Medical Sciences.
Department of Medical Epidemiology and Biostatistics, Karolinska Institutet.
(English)Manuscript (preprint) (Other academic)
Abstract [en]

Background Bone mineral density (BMD), bone size and bone turnover are independent determinants of fractures in elderly. Earlier twin studies of these phenotypes have revealed high heritability for BMD and bone area, and more moderate heritability for bone-turnover markers. No previous Scandinavian study has evaluated the genetic and environmental contribution to the variance of these phenotypes, despite the fact thatSweden andNorway have the highest osteoporotic fracture incidences worldwide.


Methods Participants were selected from the Swedish Twin Registry. All intact like-sexed twin pairs born in 1965 or earlier and living in thecounty ofUppsala were invited to participate. A total of 102 twin pairs, 45 monozygotic and 57 dizygotic, accepted the invitation to participate. All twins underwent measurement of bone mineral density and bone area using dual-energy X-ray absorptiometry DXA. Hip geometry was also calculated. Markers for bone formation (osteocalcin) and bone resorption (CrossLaps) were measured in serum.


Results We observed a strong heritability for BMD at the lumbar spine (0.85; 95% CI 0.54-0.90), the femoral neck (0.75; 95% CI 0.62-0.83), and the proximal femur (0.84; 95% CI 0.74-0.90). The values for bone area were approximately similar to those for BMD. Bone turnover markers had a slightly lower genetic influence with a value of 0.69 (0.53-0.80) for osteocalcin and 0.58 (95% CI 0.33-0.75) for CrossLaps. As a comparison, the heritabilities of body height and weight were 0.95 and 0.82, respectively.


Conclusion The high genetic influence on bone phenotypes among Swedish middle-aged and older men and women should encourage further work on the identification of specific genetic pathways. Continuing research in this area could reveal the mechanisms behind the strong genetic susceptibility of bone-related phenotypes. 



National Category
URN: urn:nbn:se:uu:diva-169594OAI: oai:DiVA.org:uu-169594DiVA: diva2:507380
Available from: 2012-03-04 Created: 2012-03-04 Last updated: 2012-07-12
In thesis
1. Genetic and Environmental Influences on Bone and Fractures
Open this publication in new window or tab >>Genetic and Environmental Influences on Bone and Fractures
2012 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

Sweden and Norway have the worldwide highest incidence of osteoporotic fractures. As these fractures constitute a tremendous and growing problem, primary prevention is of great importance. The principal causes of an osteoporotic fracture are a fall and a fragile skeleton. The aim of the studies reported in these papers was therefore to determine the genetic and environmental influences on fractures and the genetic influence on the two main reasons to the emergence of osteoporotic fractures; bone mineral density and propensity to fall.

In the present thesis, we display that the heritability of fractures is dependent on fracture site and age. With increasing age, lifestyle becomes the dominant explanatory factor. These results indicate that focus should be on lifestyle interventions for the prevention of fractures in the elderly.

Although the genetic liability to impaired balance is modest, twins with self-reported impaired balance have a substantially increased risk of osteoporotic fractures compared to their co-twin without impaired balance. Asking a patient about his or her balance might be a simple tool for future risk assessment.

The genetic influence on bone phenotypes is under strong genetic influence in Swedish adult twins. These findings are in agreement with the results from previous studies in other countries, with a lower incidence of osteoporotic fractures compared to Sweden. The high heritability of bone phenotypes together with the low heritability of fractures at old age, indicates that bone mineral density has a modest influence on fracture risk at old age.

In summary, based on the results in this thesis, more emphasis should be targeted to the prevention of falls, by strength and balance training in order to prevent the occurrence of  low energy fractures in the elderly.

Place, publisher, year, edition, pages
Uppsala: Acta Universitatis Upsaliensis, 2012. 51 p.
Digital Comprehensive Summaries of Uppsala Dissertations from the Faculty of Medicine, ISSN 1651-6206 ; 746
heritability, twin study, osteoporotic fractures, vertebral fractures, balance, bone mineral density, bone area, bone markers
National Category
Research subject
urn:nbn:se:uu:diva-169598 (URN)978-91-554-8291-6 (ISBN)
Public defence
2012-04-27, Rosénsalen, ing 95/96 nb, Akademiska Sjukhuset, Uppsala, 09:00 (Swedish)
Available from: 2012-04-04 Created: 2012-03-04 Last updated: 2012-04-19Bibliographically approved

Open Access in DiVA

No full text

Search in DiVA

By author/editor
Michaëlsson, Karl
By organisation
OrthopaedicsDepartment of Medical Sciences

Search outside of DiVA

GoogleGoogle Scholar
The number of downloads is the sum of all downloads of full texts. It may include eg previous versions that are now no longer available

Total: 160 hits
ReferencesLink to record
Permanent link

Direct link