title: Differences in bone microarchitecture between postmenopausal Chinese-American and white women.
abstract: Chinese-American women have lower rates of hip and forearm fracture than white women despite lower areal bone density (aBMD) by dual X-ray absorptiometry (DXA). We recently reported higher trabecular (D(trab) ) and cortical (D(comp) ) bone density as well as greater trabecular (Tb.Th) and cortical thickness (C.Th) but smaller bone area (CSA), as measured by high-resolution peripheral quantitative computed tomography (HR-pQCT), in premenopausal Chinese-American compared with white women. These findings may help to account for the lower fracture rate among Chinese-American women but were limited to measurements in premenopausal women. This study was designed to extend these investigations to postmenopausal Chinese-American (n = 29) and white (n = 68) women. Radius CSA was 10% smaller in the Chinese-American versus the white group (p = .008), whereas their C.Th and D(comp) values were 18% and 6% greater (p < .001 for both). Tibial HR-pQCT results for cortical bone were similar to the radius, but Tb.Th was 11% greater in Chinese-American versus white women (p = .007). Tibial trabecular number and spacing were 17% lower and 20% greater, respectively, in Chinese-American women (p < .0001 for both). There were no differences in trabecular or whole-bone stiffness estimated by microstructural finite-element analysis, but Chinese-American women had a greater percentage of load carried by the cortical bone compartment at the distal radius and tibia. There was no difference in load distribution at the proximal radius or tibia. Whole-bone finite-element analysis may indicate that the thicker, more dense cortical bone and thicker trabeculae in postmenopausal Chinese-American women compensate for fewer trabeculae and smaller bone size.
authors.affiliation: Department of Medicine, College of Physicians and Surgeons, Columbia University, New York, NY, USA. mad2037@columbia.edu
authors.forename: Marcella D
authors.initials: MD
authors.lastname: Walker
authors.forename: X Sherry
authors.initials: XS
authors.lastname: Liu
authors.forename: Emily
authors.initials: E
authors.lastname: Stein
authors.forename: Bin
authors.initials: B
authors.lastname: Zhou
authors.forename: Ervis
authors.initials: E
authors.lastname: Bezati
authors.forename: Donald J
authors.initials: DJ
authors.lastname: McMahon
authors.forename: Julia
authors.initials: J
authors.lastname: Udesky
authors.forename: George
authors.initials: G
authors.lastname: Liu
authors.forename: Elizabeth
authors.initials: E
authors.lastname: Shane
authors.forename: X Edward
authors.initials: XE
authors.lastname: Guo
authors.forename: John P
authors.initials: JP
authors.lastname: Bilezikian
mesh_terms: D015502:Absorptiometry, Photon; D001213:Asian; D015519:Bone Density / Q000502:physiology; D001842:Bone and Bones / Q000033:anatomy & histology* / Q000000981:diagnostic imaging; D005260:Female; D020342:Finite Element Analysis; D006801:Humans; D008875:Middle Aged; D009929:Organ Size; D017698:Postmenopause / Q000502:physiology*; D014057:Tomography, X-Ray Computed; D044465:White People