The genetics of proximal femur geometry, distribution of bone mass and bone mineral density

C. W. Slemenda, C. H. Turner, Munro Peacock, J. C. Christian, J. Sorbel, Siu Hui, C. C. Johnston

Research output: Contribution to journalArticle

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Abstract

To estimate genetic effects on femoral neck geometry and the distribution of bone mineral within the proximal femur a cross-sectional twin analysis was carried out at a university hospital that compared correlations in these traits in pairs of mono- and dizygotic female twins. Monozygotic (MZ, n = 51 pairs, age 49.1 ± 9.3 years) and dizygotic (DZ, n = 26 pairs, age 45.7 ± 11.3 years) twins were randomly selected from a larger sample of twins previously studied. Measurements of bone mineral density (BMD), femoral neck angles and length, cross-sectional area and moment of interia, the center of mass of the narrowest cross-section of the femoral neck, and BMDs of regions within the femoral neck were made. A summary index of the resistance of the femoral neck to forces experienced in a fall with impact on the greater trochanter (Fall Index, FI) was calculated. MZ pair intraclass correlations (rMZ) were significantly (p < 0.05) different from zero for all bone mass and femoral geometry variables (0.35 < rMZ < 0.82). DZ pair correlations (rDZ) were lower than rMZ for all variables (0.04 < rDZ < 0.52) except femoral neck length (rDZ = 0.38, rMZ = 0.36). After adjustment for BMD of the femoral neck, rMZ was significantly greater than rDZ, yielding high heritability estimates for regional BMDs (0.72 < H2 < 0.78), the center of mass of the femoral neck (H2 = 0.70, -0.04 to 1.43 95% CI) and the resistance of the femoral neck to forces experienced in a fall (FI, H2 = 0.94, 0.06 to 1.85 95% CI), but not for femoral neck length. Adjustments for age did not alter these findings. It is concluded that there are significant familial influences on the distribution of femoral bone mass and on the calculated structural strength of the proximal femur, but not on femoral neck length. If the assumptions of the twin model are correct, this is evidence for genetic factors influencing these traits.

Original languageEnglish
Pages (from-to)178-182
Number of pages5
JournalOsteoporosis International
Volume6
Issue number2
DOIs
StatePublished - 1996

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Femur Neck
Bone Density
Femur
Bone and Bones
Thigh
Dizygotic Twins
Minerals
Cross-Sectional Studies

Keywords

  • Bone density
  • Femor geometry
  • Genetics
  • Twins

ASJC Scopus subject areas

  • Medicine(all)

Cite this

The genetics of proximal femur geometry, distribution of bone mass and bone mineral density. / Slemenda, C. W.; Turner, C. H.; Peacock, Munro; Christian, J. C.; Sorbel, J.; Hui, Siu; Johnston, C. C.

In: Osteoporosis International, Vol. 6, No. 2, 1996, p. 178-182.

Research output: Contribution to journalArticle

Slemenda, C. W. ; Turner, C. H. ; Peacock, Munro ; Christian, J. C. ; Sorbel, J. ; Hui, Siu ; Johnston, C. C. / The genetics of proximal femur geometry, distribution of bone mass and bone mineral density. In: Osteoporosis International. 1996 ; Vol. 6, No. 2. pp. 178-182.
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