Comparison of Cross-Sectional Geometry of the Proximal Femur in White and Black Women from Detroit and Johannesburg

Abstract

There are known black-white differences in bone density measured by DXA but less is known about bone architecture. We compared cross-sectional geometric properties of the proximal femur in U.S. black (n ‫؍‬ 86) and white (n ‫؍‬ 151) and South African black (n ‫؍‬ 60) and white (n ‫؍‬ 48) postmenopausal women. Results are consistent with greater bone strength in the black groups in both countries.Introduction: There are well-known ethnic differences in bone density, but little is known about ethnic differences in bone architecture between U.S. and South African blacks and whites. Materials and Methods: We compared bone density and cross-sectional geometric properties of the proximal femur in 237 U.S. black (n ϭ 86) and white (n ϭ 151) and 108 South African black (n ϭ 60) and white (n ϭ 48) postmenopausal women. The proximal femur (neck, intertrochanteric region, and proximal shaft regions of interest) was measured with DXA and further analyzed with a hip structural analysis program. For each region, BMD, cross-sectional area, outer diameter, section modulus, endosteal diameter, average cortical thickness, and the buckling ratio were estimated. Results and Conclusions:In the femoral neck, in both countries, the blacks had narrower endosteal diameters (mean difference, 2.6% and 5.1% in U.S. and South African women, respectively), thicker cortices (9.3% and 11.0%), and a lower buckling ratio (11.6% and 15.2%) despite a similar outer diameter. In the intertrochanteric region, the whites had a greater outer diameter (2.2% and 3.0% in U.S. and South African women, respectively), lower cross-sectional area (4.8% and 7.2%), and a higher buckling ratio (7.6% and 3.6%). There are fewer differences in the shaft. Compared with South African whites, U.S. whites had wider (mean difference 2.9%) femoral necks and a greater section modulus (6.4%) in the shaft. U.S. whites also had greater cross-sectional area in both the neck and shaft (5.2% and 4.6%, respectively). The U.S. blacks had significantly greater outer diameters, cross-sectional areas, endosteal diameters, and section moduli in the neck region compared with South African blacks. Our observations are consistent with greater bone strength in the black groups in both countries, and they also suggest that there are fewer differences between the same ethnic groups in the two countries than there are between different ethnic groups within a country.

Ethnic differences in femur geometry in the women's health initiative observational study

“…Region sizes are effectively smaller among AA women because their femoral neck and intertrochanter regions are significantly narrower. This was previously observed at the narrow neck by Nelson et al [11,12] in US and South African women of African descent and in AA men by Travison and colleagues at both the narrow-neck and intertrochanter regions [5]. At the narrow neck region, SM and CSA were significantly greater Fig.…”

“…An earlier small study conducted at an ancillary clinical center of the WHI, compared femur geometries between AA and white postmenopausal women from the Detroit area [11]. That study and a follow-up comparison with black and white women from Johannesburg, South Africa [12] showed smaller diameters underlying the higher BMD in groups of African origin compared to whites of both countries. Studies of femur geometry in other ethnic groups is currently lacking in women, but a recent cross-sectional comparison by Travison et al [13] evaluated men of white, black and Hispanic origin in the Boston area.…”

Adaptations in tibial cortical thickness and total volumetric bone density in postmenopausal South Asian women with small bone size

“…Measures of bone geometry have been associated with prediction of fracture risk [3][4][5], leading to considerable research assessing bone geometry in different population groups [6][7][8][9]. However, this has been limited within the female South Asian population, with most studies only assessing areal Bone Mineral Density, using dual-x ray absorptiometry (DXA).…”

“…South Asian women have also been found to have a higher incidence of wrist fracture than Chinese women, although South Asians did not differ from White Caucasian women on these measures [1,2]. To investigate these epidemiological findings of increased osteoporosis incidence, but similar fracture rates, it is important to examine the differences in bone geometry between South Asians and White Caucasians.Measures of bone geometry have been associated with prediction of fracture risk [3][4][5], leading to considerable research assessing bone geometry in different population groups [6][7][8][9]. However, this has been limited within the female South Asian population, with most studies only assessing areal Bone Mineral Density, using dual-x ray absorptiometry (DXA).…”

Association and linkage analysis of COL1A1 and AHSG gene polymorphisms with femoral neck bone geometric parameters in both Caucasian and Chinese nuclear families

“…To date, only a few studies have focused on the comparison of bone geometric parameters across different races [27,28] , but no genetic study has simultaneously investigated the contribution of bone candidate genes on the variation of bone geometric parameters in both Caucasians and Chinese. Thus, in the present study, we first compared bone geometric parameters of FN between the Caucasian and Chinese population and then tested the effect of the AHSG and COL1A1 genes on the variation of bone geometric parameters of FN in both Caucasians and Chinese, our study would contribute to understand the various genetic determination of bone geometry between different ethnic populations.…”