title: Heritability of Thoracic Spine Curvature and Genetic Correlations With Other Spine Traits: The Framingham Study.
abstract: Hyperkyphosis is a common spinal disorder in older adults, characterized by excessive forward curvature of the thoracic spine and adverse health outcomes. The etiology of hyperkyphosis has not been firmly established, but may be related to changes that occur with aging in the vertebrae, discs, joints, and muscles, which function as a unit to support the spine. Determining the contribution of genetics to thoracic spine curvature and the degree of genetic sharing among co-occurring measures of spine health may provide insight into the etiology of hyperkyphosis. The purpose of our study was to estimate heritability of thoracic spine curvature using T4-T12kyphosis (Cobb) angle and genetic correlations between thoracic spine curvature and vertebral fracture, intervertebral disc height narrowing, facet joint osteoarthritis (OA), lumbar spine volumetric bone mineral density (vBMD), and paraspinal muscle area and density, which were all assessed from computed tomography (CT) images. Participants included 2063 women and men in the second and third generation offspring of the original cohort of the Framingham Study. Heritability of kyphosis angle, adjusted for age, sex, and weight, was 54% (95% confidence interval [CI], 43% to 64%). We found moderate genetic correlations between kyphosis angle and paraspinal muscle area (ρˆG, -0.46; 95% CI, -0.67 to -0.26), vertebral fracture (ρˆG, 0.39; 95% CI, 0.18 to 0.61), vBMD (ρˆG, -0.23; 95% CI, -0.41 to -0.04), and paraspinal muscle density (ρˆG, -0.22; 95% CI, -0.48 to 0.03). Genetic correlations between kyphosis angle and disc height narrowing (ρˆG, 0.17; 95% CI, -0.05 to 0.38) and facet joint OA (ρˆG, 0.05; 95% CI, -0.15 to 0.24) were low. Thoracic spine curvature may be heritable and share genetic factors with other age-related spine traits including trunk muscle size, vertebral fracture, and bone mineral density. © 2016 American Society for Bone and Mineral Research.
authors.affiliation: Institute for Aging Research, Hebrew SeniorLife, Boston, MA, USA.|Department of Medicine, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, MA, USA.
authors.forename: Michelle S
authors.initials: MS
authors.lastname: Yau
authors.affiliation: Department of Biostatistics, Boston University School of Public Health, Boston, MA, USA.
authors.forename: Serkalem
authors.initials: S
authors.lastname: Demissie
authors.affiliation: Department of Biostatistics, Boston University School of Public Health, Boston, MA, USA.
authors.forename: Yanhua
authors.initials: Y
authors.lastname: Zhou
authors.affiliation: Center for Advanced Orthopaedic Studies, Beth Israel Deaconess Medical Center, Boston, MA, USA.|Department of Orthopedic Surgery, Harvard Medical School, Boston, MA, USA.
authors.forename: Dennis E
authors.initials: DE
authors.lastname: Anderson
authors.affiliation: Institute for Aging Research, Hebrew SeniorLife, Boston, MA, USA.|Department of Medicine, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, MA, USA.
authors.forename: Amanda L
authors.initials: AL
authors.lastname: Lorbergs
authors.affiliation: Institute for Aging Research, Hebrew SeniorLife, Boston, MA, USA.|Department of Medicine, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, MA, USA.
authors.forename: Douglas P
authors.initials: DP
authors.lastname: Kiel
authors.affiliation: Department of Orthopedic Surgery, Harvard Medical School, Boston, MA, USA.
authors.forename: Brett T
authors.initials: BT
authors.lastname: Allaire
authors.affiliation: Institute for Aging Research, Hebrew SeniorLife, Boston, MA, USA.
authors.forename: Laiji
authors.initials: L
authors.lastname: Yang
authors.affiliation: Department of Biostatistics, Boston University School of Public Health, Boston, MA, USA.|National Heart Lung and Blood Institute Framingham Heart Study, Framingham, MA, USA.
authors.forename: L Adrienne
authors.initials: LA
authors.lastname: Cupples
authors.affiliation: Institute for Aging Research, Hebrew SeniorLife, Boston, MA, USA.|Department of Medicine, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, MA, USA.
authors.forename: Thomas G
authors.initials: TG
authors.lastname: Travison
authors.affiliation: Center for Advanced Orthopaedic Studies, Beth Israel Deaconess Medical Center, Boston, MA, USA.|Department of Orthopedic Surgery, Harvard Medical School, Boston, MA, USA.
authors.forename: Mary L
authors.initials: ML
authors.lastname: Bouxsein
authors.affiliation: Institute for Aging Research, Hebrew SeniorLife, Boston, MA, USA.|Faculty of Medicine in the Galilee, Bar Ilan University, Safed, Israel.
authors.forename: David
authors.initials: D
authors.lastname: Karasik
authors.affiliation: Institute for Aging Research, Hebrew SeniorLife, Boston, MA, USA.|Department of Medicine, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, MA, USA.
authors.forename: Elizabeth J
authors.initials: EJ
authors.lastname: Samelson
mesh_terms: D017677:Age Distribution; D000368:Aged; D000465:Algorithms; D005260:Female; D006801:Humans; D040582:Inheritance Patterns / Q000235:genetics*; D007738:Kyphosis / Q000000981:diagnostic imaging / Q000235:genetics; D008297:Male; D008875:Middle Aged; D010641:Phenotype; D013121:Spinal Curvatures / Q000000981:diagnostic imaging / Q000235:genetics*; D013904:Thoracic Vertebrae / Q000000981:diagnostic imaging / Q000473:pathology*; D014057:Tomography, X-Ray Computed
keywords: AGING; DISEASES AND DISORDERS RELATED TO BONE; EPIDEMIOLOGY; GENETIC RESEARCH; QCT