Population bone mineral density measurements for Chinese women and men in Hong Kong

Clinical and Radiological Outcomes of Rectangular Tapered Cementless Stem According to Proximal Femoral Geometry in Elderly Asian Patients

Purpose

A retrospective analysis of mid- to long-term clinical and radiological outcomes of Korean patients over 60 years of age who underwent hip arthroplasty using a cementless rectangular tapered stem according to Dorr proximal femur geography.

Materials and Methods

From January 2007 to December 2013, 107 patients (112 hips) underwent hip arthroplasty using the C2 stem. The mean age of patients was 77.4 years (range, 60–91 years) and the mean follow-up duration was 91.1 months (range, 60–116 months). All patients were evaluated clinically and radiologically with special attention to Dorr femoral bone classification, implant fixation, radiolucent line (RLL), and thigh pain.

Results

All implants demonstrated radiographic evidence of stable fixation by bone ingrowth without any change in position. The mean Harris hip score improved from 65.5±16.0 (preoperative) to 90.5±15.9 (final follow-up) (P<0.001). Incidence of RLLs, stress shielding, and thigh pain was highest in patients with Dorr type A (RLL, P=0.021; stress shielding, P=0.030; thigh pain, P<0.001). One stem revision was performed due to deep infection. The Kaplan–Meier survival rate of the femoral stem was 97.6%.

Conclusion

The overall survival rate of the C2 stems was greater than 97%; there were no significant differences in survival of the C2 stem according to the Dorr classification. The incidences of RLL of thigh pain and RLL were significantly different among Dorr classifications and (highest in patients with Dorr type A).

Chinese Women in Both the United States and Hong Kong Have Cortical Microstructural Advantages and More Trabecular Plates Compared With White Women

We cross-sectionally compared racial differences in bone quality between Chinese women in the United States (US) and Hong Kong (HK) with white women. A total of 514 women were included. We measured bone geometry, mass, microstructure, and stiffness by high-resolution peripheral quantitative computed tomography (HR-pQCT), individual trabecula segmentation (ITS), and microfinite element analysis (μFEA). After adjustment for age and body mass index (BMI), premenopausal Chinese women in the US and HK had smaller bone area but greater radial cortical (Ct.) thickness and Ct. and trabecular (Tb.) volumetric bone mineral density (vBMD) versus white women but did not differ from each other. At the radius, Tb. number was lower and spacing greater in Chinese women from HK and the US versus white women, whereas Chinese women did not differ from each other. Tb. thickness was highest in Chinese women from HK, intermediate in Chinese-Americans, and lowest in white women. Chinese women had more trabecular plates versus white women, leading to greater age- and BMI-adjusted stiffness for premenopausal Chinese women in HK and the US (both p < 0.05) versus white women. Tibial differences were similar in premenopausal women; analogous trends in microstructure were present in postmenopausal women at the tibia, although stiffness did not differ. In contrast, at the radius, cortical, plate-to-rod ratio, and stiffness were similar between postmenopausal HK and white women. Adjusting for age, weight, and height rather than age and BMI tended to reduce differences in bone size and Tb. parameters but accentuate cortical differences such that Chinese premenopausal women in both locations and postmenopausal women from HK had higher stiffness at both skeletal sites compared with white women. Compared with white women, Chinese women in the US and HK have vBMD and microstructural advantages leading to higher or similar mechanical competence in pre- and postmenopausal women, respectively, despite smaller bone size.

Incidence of Vertebral Fractures in Women with Systemic Lupus Erythematosus After 8 Years of Follow-Up

The aim of this study was to evaluate possible associations between potential risk factors and the occurrence of established vertebral fractures (VF) in Mexican patients with systemic lupus erythematosus (SLE). Consecutive patients with SLE were enrolled in a prospective, observational study from 2006 to 2015. Information on potential risk factors, including demographics, clinical data, and bone mineral density (BMD) at the lumbar spine and hip on dual-energy X-ray absorptiometry was collected at baseline and follow-up. Semiquantitative analysis was used to determine incident VF on lateral thoracic and lumbar radiographs, defined as any vertebral body graded normal at baseline and at least mildly deformed (20-25% reduction or more in any vertebral height) during follow-up. Differences in baseline characteristics were assessed in patients with and without new radiographic VF. Of 110 SLE patients included, with a median follow-up of 8 (IQR 8-9) years, 22 (20%) had radiographic VF at baseline; 35 (32%) patients had a new VF. The annual incidence rate of new morphometric VF was 3.5 (95% CI 2.4-4.91) per 100 patient/years. Most fractures were mild or moderate and biconcave shaped. Incident VF were significantly associated with baseline BMD at the total hip and longer disease duration. Cumulative glucocorticoid dose, postmenopausal status, and previous prevalent VF were not associated with VF. In this SLE cohort in daily clinical practice, new VF were frequently present in SLE patients, especially those with longer disease duration and low-hip BMD.

A trabecular plate-like phenotype is overrepresented in Chinese-American versus Caucasian women

This study used extreme phenotype selection to define two trabecular bone phenotypes in a cohort of Chinese-American and Caucasian women. A trabecular plate-predominant phenotype is more common in Chinese-Americans while the rod-predominant phenotype is more typical of Caucasians. The robustness of these phenotypic associations with respect to lifestyle factors suggests that this trait may have a genetic basis and that these phenotypes can be utilized in future genetic studies.

INTRODUCTION

Compared to Caucasians, Chinese-Americans have more plate-like trabecular bone when measured by individual trabecula segmentation (ITS). These findings suggest a phenotypic difference between the races, which may be amenable to genetic analysis. We sought to identify a single ITS plate trait to pursue in genetic studies by conducting an extreme phenotype selection strategy to numerically define two distinct phenotypes-plate-like and rod-like-and determine whether the selected phenotypic associations were independent of lifestyle factors in order to conduct future genetic studies.

METHODS

A previously described cohort of 146 Chinese-American and Caucasian women with high-resolution peripheral quantitative computed tomography imaging and ITS analyses were studied with logistic regression and receiver operator characteristic analyses.

RESULTS

The tibial plate-to-rod (TPR) ratio was the best ITS discriminator of race. Using extreme phenotypic selection, two TPR ratio phenotypes were defined numerically: plate-like as a TPR ratio value in the highest quartile (≥1.336) and rod-like as a TPR ratio value in the lowest quartile (≤0.621). Women with a plate-like phenotype were 25.7 times more likely (95 % CI 7.3-90.1) to be Chinese-American than women with rod-like morphology. After controlling for constitutional and lifestyle covariates, women in the highest vs. lowest TPR ratio quartile were 85.0 times more likely (95 % CI 12.7-568.0) to be Chinese-American.

CONCLUSION

Using extreme phenotype selection, we defined a plate- and rod-like trabecular bone phenotype for the TPR ratio trait. The former phenotype is more common in Chinese-American women, while the latter is more typical of Caucasian women. The robustness of these phenotypic associations after controlling for differences in constitution and lifestyle suggest that the TPR ratio may have a genetic basis and that the extreme phenotypes defined in this analysis can be utilized for future studies.

Lower cortical porosity and higher tissue mineral density in Chinese American versus white women

Asian women have lower rates of hip and forearm fractures compared to other racial groups despite lower areal bone mineral density (aBMD). We have demonstrated microarchitectural differences, including greater cortical thickness (Ct.Th) and cortical volumetric BMD (Ct.BMD), in Chinese American versus white women. Yet it is not known whether greater Ct.BMD in Chinese American women is a result of greater tissue mineral density (TMD) or reduced cortical porosity (Ct.Po). Using an advanced segmentation algorithm based on high-resolution peripheral quantitative computed tomography (HR-pQCT) images, we tested the hypothesis that Chinese American women have better cortical skeletal integrity owing to lower Ct.Po and higher Ct.TMD compared with white women. A total of 78 Chinese American women (49 premenopausal and 29 postmenopausal) and 114 white women (46 premenopausal and 68 postmenopausal) were studied. Premenopausal Chinese American versus white women had greater Ct.Th, Ct.BMD, and Ct.TMD at both the radius and tibia, and decreased Ct.Po (p < 0.05). A similar pattern was observed between postmenopausal Chinese American and white women. As expected, postmenopausal versus premenopausal women had lower Ct.BMD at the radius and tibia in both races (p < 0.001). Ct.Po largely increased between premenopausal and postmenopausal women, whereas Ct.TMD decreased by 3% to 8% (p < 0.001) in both races. Age-related differences in Ct.Po and Ct.TMD did not differ by race. In summary, both reduced Ct.Po and greater Ct.TMD explain higher Ct.BMD in Chinese American versus white women. Thicker and preserved cortical bone structure in Chinese American women may contribute to greater resistance to fracture compared to white women.

The Chinese skeleton: insights into microstructure that help to explain the epidemiology of fracture

Osteoporotic fractures are a major public health problem worldwide, but incidence varies greatly across racial groups and geographic regions. Recent work suggests that the incidence of osteoporotic fracture is rising among Asian populations. Studies comparing areal bone mineral density and fracture across races generally indicate lower bone mineral density in Asian individuals including the Chinese, but this does not reflect their relatively low risk of non-vertebral fractures. In contrast, the Chinese have relatively high vertebral fracture rates similar to that of Caucasians. The paradoxically low risk for some types of fractures among the Chinese despite their low areal bone mineral density has been elucidated in part by recent advances in skeletal imaging. New techniques for assessing bone quality non-invasively demonstrate that the Chinese compensate for smaller bone size by differences in hip geometry and microstructural skeletal organization. Studies evaluating factors influencing racial differences in bone remodeling, as well as bone acquisition and loss, may further elucidate racial variation in bone microstructure. Advances in understanding the microstructure of the Chinese skeleton have not only helped to explain the epidemiology of fracture in the Chinese, but may also provide insight into the epidemiology of fracture in other races as well.

Premenopausal and postmenopausal differences in bone microstructure and mechanical competence in Chinese-American and white women

Compared to white women, premenopausal Chinese-American women have more plate-like trabecular (Tb) bone. It is unclear whether these findings are relevant to postmenopausal women and if there are racial differences in the deterioration of bone microarchitecture with aging. We applied individual trabecula segmentation and finite element analysis to high-resolution peripheral quantitative computed tomography images in premenopausal and postmenopausal Chinese-American and white women to quantify within-race age-related differences in Tb plate-versus-rod microarchitecture and bone stiffness. Race-menopause status interactions were assessed. Comparisons between races within menopause status were adjusted for age, height and weight. Comparisons between premenopausal and postmenopausal women were adjusted for height and weight. Adjusted analyses at the radius indicated that premenopausal Chinese-Americans had a higher plate bone volume fraction (pBV/TV), Tb plate-to-rod ratio (P-R ratio), and greater plate-plate junction densities (P-P Junc.D) versus white women (all p < 0.01), resulting in 27% higher Tb stiffness (p < 0.05). Greater cortical thickness and density (Ct.Th and Dcort) and more Tb plates led to 19% greater whole bone stiffness (p < 0.05). Postmenopausal Chinese-Americans had similar pBV/TV and P-P Junc.D, yet a higher P-R ratio versus white women. Postmenopausal Chinese-American versus white women had greater Ct.Th, Dcort, and relatively intact Tb plates, resulting in similar Tb stiffness but 12% greater whole bone stiffness (p < 0.05). In both races, Ct.Th and Dcort were lower in postmenopausal versus premenopausal women and there were no differences between races. Tb plate parameters were also lower in postmenopausal versus premenopausal women, but age-related differences in pBV/TV, P-R ratio, and P-P Junc D were greater (p < 0.05) in Chinese-Americans versus white women. There are advantages in cortical and Tb bone in premenopausal Chinese-American women. Within-race cross-sectional differences between premenopausal and postmenopausal women suggest greater loss of plate-like Tb bone with aging in Chinese-Americans, though thicker cortices and more plate-like Tb bone persists.

Volumetric bone mineral density at the spine and hip in Chinese American and White women

This study evaluated racial differences in bone size and volumetric density at the spine and hip in pre- and postmenopausal Chinese American and White women. Compared with White women, Chinese American women have greater cortical volumetric bone density (vBMD) at the hip, congruent with the results at the peripheral skeleton.

INTRODUCTION

Chinese American women have lower rates of fracture than White women despite lower areal bone density. At the forearm and tibia, however, Chinese American women have higher cortical vBMD as well as greater trabecular and cortical thickness, but smaller bone area as measured by high-resolution peripheral quantitative computed tomography (HR-pQCT) compared with White women. Since HR-pQCT data are obtained at peripheral sites, it is unclear whether these differences are relevant to the clinically important lumbar spine and hip. This study assesses racial differences in bone size and vBMD at the spine and hip in Chinese American and White women.

METHODS

QCT of the spine and hip was measured to assess racial differences in bone size, structure, and vBMD in pre- (n = 83) and postmenopausal (n = 50) Chinese American and White women. Data were adjusted for weight, height, physical activity, total calcium intake, parathyroid hormone, and 25-hydroxyvitamin D levels.

RESULTS

Among premenopausal women, lumbar spine trabecular vBMD was 5.8% greater in Chinese American versus White women (p = 0.01). At the hip, cortical vBMD was 3% greater at the femoral neck (p = 0.05) and 3.6% greater at the total hip (p = 0.01) in premenopausal Chinese American compared with White women. Among postmenopausal women, there was no difference in lumbar spine trabecular vBMD. Cortical vBMD was 4% greater at the total hip (p = 0.02) and tended to be greater at the femoral neck (p = 0.058) in Chinese American versus White women.

CONCLUSIONS

Consistent with earlier findings in the peripheral skeleton, cortical vBMD is greater at the hip in Chinese American versus White women.

Epidemiology and structural basis of racial differences in fragility fractures in Chinese and Caucasians

Chinese have similar vertebral fracture prevalence but lower incidence of hip and distal forearm fractures than in Caucasians. The underlying structural and biomechanical basis of racial differences in bone fragility is still largely undefined but Chinese assemble their smaller appendicular skeleton with thicker cortices and trabeculae compared with Caucasians. Vertebral fracture prevalence is similar by race, but the incidence of hip and distal forearm fractures is lower in Chinese than in Caucasians. This racial dimorphism cannot be explained by differences in areal bone mineral density (aBMD) as aBMD is lower in Chinese mainly due to their smaller size. The underlying structural and biomechanical basis of racial differences in bone fragility is still largely undefined but Chinese assemble their smaller appendicular skeleton with more mineralised bone matrix within it; the cortices are thicker and perhaps less porous while trabeculae are fewer but thicker and more connected. This configuration produces a bone with a lower surface/volume ratio, which in turn reduces the surface available for remodelling to occur upon so that the lower surface/volume ratio may make the bone less exposed to remodelling and the thicker cortices and trabeculae less vulnerable to remodelling when it does occur during advancing age. However, prospective studies are needed to define racial differences at the age of onset, rate of bone loss from the intracortical, endocortical and trabecular components of the endosteal envelope and bone formation upon the periosteal envelope; notions of bone 'loss' are derived mainly from cross-sectional studies. Studies of the site- and surface-specific changes in bone modelling and remodelling are needed to better define racial differences in bone fragility in old age.

Classic yin and yang tonic formula for osteopenia: study protocol for a randomized controlled trial

Background

Osteoporosis is a growing worldwide problem, with the greatest burden resulting from fractures. Nevertheless, the majority of fractures in adults occur in those with "osteopenia" (bone mineral density (BMD) only moderately lower than young normal individuals). Since long-term drug therapy is an expensive option with uncertain consequences and side effects, natural herbal therapy offers an attractive alternative. The purpose of this study is to evaluate the effect on BMD and safety of the Classic Yin and Yang Tonic Formula for treatment of osteopenia and to investigate the mechanism by which this efficacy is achieved.

Methods/design

We propose a multicenter double-blind randomized placebo-controlled trial to evaluate the efficacy and safety of the Classic Yin and Yang Tonic Formula for the treatment of osteopenia. Participants aged 55 to 75 with low bone mineral density (T-score between -1 and -2.5) and kidney deficiency in TCM will be included and randomly allocated into two groups: treatment group and control group. Participants in the treatment group will be treated with Classic Yin and Yang Tonic Granule, while the controlled group will receive placebo. Primary outcome measure will be BMD of the lumbar spine and proximal femur using dual-energy X-ray absorptiometry. Secondary outcomes will include pain intensity measured with visual analogue scales, quality of life, serum markers of bone metabolism, indices of Neuro-endocrino-immune network and safety.

Discussion

If the Classic Yin and Yang Tonic Formula can increase bone mass without adverse effects, it may be a novel strategy for the treatment of osteoporosis. Furthermore, the mechanism of the Chinese medical formula for osteoporosis will be partially elucidated.

Trial registration

This study is registered at ClinicalTrials.gov, NCT01271647.

Better skeletal microstructure confers greater mechanical advantages in Chinese-American women versus white women

Despite lower areal bone mineral density (aBMD), Chinese-American women have fewer fractures than white women. We hypothesized that better skeletal microstructure in Chinese-American women in part could account for this paradox. Individual trabecula segmentation (ITS), a novel image-analysis technique, and micro-finite-element analysis (µFEA) were applied to high-resolution peripheral quantitative computed tomography (HR-pQCT) images to determine bone microarchitecture and strength in premenopausal Chinese-American and white women. Chinese-American women had 95% and 80% higher plate bone volume fraction at the distal radius and tibia, respectively, as well as 20% and 18% higher plate number density compared with white women (p < .001). With similar rodlike characteristics, the plate-to-rod ratio was twice as high in the Chinese-American than in white trabecular bone (p < .001). Plate-rod junction density, a parameter indicating trabecular network connections, was 37% and 29% greater at the distal radius and tibia, respectively, in Chinese-American women (p < .002). Moreover, the orientation of the trabecular bone network was more axially aligned in Chinese-American women because axial bone volume fraction was 51% and 32% higher at the distal radius and tibia, respectively, than in white women (p < .001). These striking differences in trabecular bone microstructure translated into 55% to 68% (distal radius, p < .001) and 29% to 43% (distal tibia, p < .01) greater trabecular bone strength, as assessed by Young's moduli, in the Chinese-American versus the white group. The observation that Chinese-American women have a major microstructural advantage over white women may help to explain why their risk of fracture is lower despite their lower BMD.

Differences in bone microarchitecture between postmenopausal Chinese-American and white women

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.

Application of high-resolution skeletal imaging to measurements of volumetric BMD and skeletal microarchitecture in Chinese-American and white women: explanation of a paradox

Asian women have lower rates of hip and forearm fractures despite lower areal BMD (aBMD) by DXA compared with white women and other racial groups. We hypothesized that the lower fracture rates may be explained by more favorable measurements of volumetric BMD (vBMD) and microarchitectural properties, despite lower areal BMD. To address this hypothesis, we used high-resolution pQCT (HRpQCT), a new method that can provide this information noninvasively. We studied 63 premenopausal Chinese-American (n = 31) and white (n = 32) women with DXA and HRpQCT. aBMD by DXA did not differ between groups for the lumbar spine (1.017 +/- 0.108 versus 1.028 +/- 0.152 g/cm(2); p = 0.7), total hip (0.910 +/- 0.093 versus 0.932 +/- 0.134 g/cm(2); p = 0.5), femoral neck (0.788 +/- 0.083 versus 0.809 +/- 0.129 g/cm(2); p = 0.4), or one-third radius (0.691 +/- 0.052 versus 0.708 +/- 0.047 g/cm(2); p = 0.2). HRpQCT at the radius indicated greater trabecular (168 +/- 41 versus 137 +/- 33 mg HA/cm(3); p = <0.01) and cortical (963 +/- 46 versus 915 +/- 42 mg HA/cm(3); p < 0.0001) density; trabecular bone to tissue volume (0.140 +/- 0.034 versus 0.114 +/- 0.028; p = <0.01); trabecular (0.075 +/- 0.013 versus 0.062 +/- 0.009 mm; p < 0.0001) and cortical thickness (0.98 +/- 0.16 versus 0.80 +/- 0.14 mm; p < 0.0001); and lower total bone area (197 +/- 34 versus 232 +/- 33 mm(2); p = <0.001) in the Chinese versus white women and no difference in trabecular number, spacing, or inhomogeneity before adjustment for covariates. Similar results were observed at the weight-bearing tibia. At the radius, adjustment for covariates did not change the direction or significance of differences except for bone, which became similar between the groups. However, at the tibia, adjustment for covariates attenuated differences in cortical BMD and bone area and accentuated differences in trabecular microarchitecture such that Chinese women additionally had higher trabecular number and lower trabecular spacing, as well as inhomogeneity after adjustment. Using the high-resolution technology, the results provide a mechanistic explanation for why Chinese women have fewer hip and forearm fractures than white women.

Loss of otolith function with age is associated with increased postural sway measures

Loss of balance and increased fall risk is a common problem associated with aging. Changes in vestibular function occur with aging but the contribution of reduced vestibular otolith function to fall risk remains unknown. We examined a population of 151 healthy individuals (aged 21-93) for both balance (sway measures) and ocular counter-rolling (OCR) function. We assessed balance function with eyes open and closed on a firm surface, eyes open and closed on a foam surface and OCR during +/-20 degree roll tilt at 0.005 Hz. Subjects demonstrated a significant age-related reduction in OCR and increase in postural sway. The effect of age on OCR was greater in females than males. The reduction in OCR was strongly correlated with the mediolateral measures of sway with eyes closed. This correlation was also present in the elderly group alone, suggesting that aging alone does not account for this effect. OCR decreased linearly with age and at a greater rate in females than males. This loss of vestibular otolith-ocular function is associated with increased mediolateral measures of sway which have been shown to be related to increased risk of falls. These data suggest a role for loss of otolith function in contributing to fall risk in the elderly. Further prospective, longitudinal studies are necessary to confirm these findings.

Age-related trends in phalangeal bone mineral density in Sri Lankan men and women aged 20 years or more

To establish normative reference values and to study the age-related trends in phalangeal bone mineral density (BMD), 4504 male and 5215 female volunteers aged 20 yr or more were recruited from 7 provinces from October 2004 to October 2005. Subjects suffering from diseases and those who were taking medications, which could affect BMD were excluded from the analysis (n=530). Phalangeal BMD was measured in the nondominant hand using an AccuDXA. Men and women were categorized to age groups of 20-29 (1087 men and 1079 women), 30-39 (1122 men and 1146 women), 40-49 (1148 men and 1455 women), 50-59 (810 men and 1111 women), 60-69 (250 men and 335 women), and 70 yr or more (87 men and 94 women). Mean BMDs (SD) of men in above categories were 0.595 (0.057), 0.603 (0.061), 0.591 (0.066), 0.576 (0.069), 0.558 (0.077), and 0.522 (0.079) g/cm2, respectively. The corresponding BMDs (SD) in women were 0.495 (0.057), 0.506 (0.062), 0.502 (0.064), 0.462 (0.072), 0.406 (0.072), and 0.340 (0.055) g/cm2, respectively. Peak BMD was seen in 30-39-age category in both sexes. Women after 50 yr lost BMD at a rate of 0.006 (standard error 0.0003) g/cm2/yr, whereas the corresponding value in men was 0.002 (standard error 0.0001) g/cm2/yr. These data provide normative reference data for the calculation of T-score and Z-score for phalangeal BMD in Sri Lankan men and women aged more than 20 yr.

Race and diet interactions in the acquisition, maintenance, and loss of bone

Racial differences in bone become apparent during puberty. Studies of areal bone mineral density (aBMD) generally show the greatest aBMD in African Americans followed by American white, Hispanic, and Native Americans, with the least aBMD in Asian Americans. Racial differences in fracture risk, however, do not exactly follow racial variation in aBMD. These group differences in bone mass are largely explained by differences in bone size, although calcium intake and physical activity are also significant predictors of aBMD and bone mineral content. Racial differences in calcium metabolism, as influenced by calcium and sodium intake, explain much of the black vs. white differences in skeletal calcium accretion during puberty. The relative importance of calcium and sodium in calcium metabolism has not yet been elucidated among Asians. Predictors of aBMD have been reported for African American and American white adults and predictors of aBMD in Chinese American women have recently been studied. Much remains to be studied regarding interactions between race and diet.

Prevalence of osteoporosis and reference data for lumbar spine and hip bone mineral density in a Korean population

The aims of this study were to establish reference data for bone mineral density (BMD) at central skeletal sites using Lunar dual-energy X-ray absorptiometry (DXA), and to estimate the age-and sex-specific prevalence of osteoporosis in a Korean population. We performed a population-based, cross-sectional study. The subjects were 4148 (1810 men and 2338 women) Korean adults, aged 20-79 years. The BMD for central sites (lumbar spine, femoral neck, trochanter, and Ward's triangle) were measured by DXA. The standardized prevalence of osteoporosis among individual aged 50-79 years in lumbar spine, femoral neck, Ward's triangle, and trochanter was 40.1%, 12.4%, 28.4%, and 4.4% in women and 6.5%, 5.9%, 3.7%, and 1.6% in men, respectively. In women, peak BMD occurred in the age range 40-49 years for the femoral neck and trochanter, 30-39 years for the lumbar spine, and 20-29 years for Ward's triangle. In men, peak BMD values were observed at 20-29 years for all measured sites. This study establishes a normative database for BMD at central skeletal sites using dual-energy X-ray absorptiometry and provides more reliable information on the prevalence of osteoporosis in Korea.

Establishment of peak bone mineral density in Southern Chinese males and its comparisons with other males from different regions of China

Peak bone mineral density (PBMD) is an important determinant of osteoporotic fracture and a precondition for correct diagnosis of osteoporosis. The objective of this study was to establish the reference data of PBMD at the lumber spine and hip in Southern Chinese males. Bone mineral density (BMD) was measured at the lumbar spine and hip (femoral neck, trochanter, intertrochanter, and total) in 1155 Chinese men aged 15-39 years, using dual-energy X-ray absorptiometry (DXA). We utilized a fit curve method to determine the best age range over which to calculate PBMD. Our results indicated that the PBMD was observed at the age range of 18-25 years at the various sites. The mean value and standard deviation of PBMD was 0.753 +/- 0.117, 1.156 +/- 0.148, 0.896 +/- 0.120, 0.989 +/- 0.122, and 0.980 +/- 0.116 g/cm2 at the trochanter, intertrochanter, femoral neck, total hip, and spine, respectively. When the present PBMD reference was compared with the documented PBMD reference of males from other regions of China, we found great difference in standardized PBMD between Changsha males and those from other regions of China. The PBMD for Chinese males in Changsha at the various sites were 3.19%-11.33% lower than that for American Caucasian males. In conclusion, the PBMD at the spine and hip may be used as normal reference data for Southern Chinese males in Changsha instead of documented PBMD from other regions of China and the manufacturer's reference data.

Bone health of immigrant Chinese women living in New York City

Osteoporosis is a serious national and global public health problem, but data on bone health are limited for Asian women living in the U.S., the majority of whom are Chinese. For this study, we measured bone mineral density (BMD) by dual energy X-ray densitometry (DXA) at the lumbar spine and hip region in 300 immigrant Chinese women, ages 40-90 y, living in New York City. We also collected demographic and health data, information about knowledge and care for osteoporosis, and anthropometric measures, and estimated calcium intake from the women. In our sample, 55% had osteoporosis and 38% had low bone mass (osteopenia). Older age, lower body mass index (BMI), and shorter height were associated with lower BMD at all sites. Years lived in the U.S. and number of children were also associated with lower BMD of the lumbar spine. Chinese women who emigrated from Mainland China had lower BMD at the lumbar spine and femoral neck than Chinese women who emigrated from Hong Kong, after adjusting for potential confounders. Both groups of immigrant women had lower BMD at all sites than a national sample of U.S. Caucasian women. Although the women in our study had generally poor knowledge about osteoporosis, most could identify at least one food rich in calcium. The large number of immigrant Chinese women in New York City with osteoporosis calls for major efforts to increase awareness, prevention, diagnosis, and treatment of this condition in this susceptible population.

Age-related anthropometric remodelling resulting in increased and redistributed adiposity is associated with increases in the prevalence of cardiovascular risk factors in Chinese subjects

BACKGROUND

Ageing promotes increases in the prevalence of components of the metabolic syndrome, which obesity often underlies.

METHODS

We report the relationship between ageing, obesity and other cardiovascular risk factors in 694 community-based Chinese subjects in gender-specific groups of three age ranges: 20.0-39.9 (young), 40.0-59.9 (middle-aged) and 60.0-79.9 (old-aged) years.

RESULTS

Body mass index (BMI) values were similar in males in each age group, but waist and percentage body fat increased (6.6, and 39.5%, both p < 0.001, respectively), from young to old-age groups, as did blood pressure and glycated haemoglobin levels (all p < 0.001). In the females, increases (all p < 0.001) in percentage body fat (29.3%) were accompanied by greater increases in BMI (10.3%) and waist (19.2%) than the males. Blood pressure, glycated haemoglobin, total and LDL-cholesterol and triglyceride levels increased linearly with age (all p < 0.001).

CONCLUSION

Age-related increases in central adiposity and percentage body fat were associated with increasingly adverse cardiovascular risk factor profiles.

A referent bone mineral density database for Chinese American women

INTRODUCTION

While osteoporosis is common among women of Chinese descent, a readily available bone mineral density (BMD) referent database for Chinese American women does not exist. Fracture risk among this population is currently assessed using a Caucasian reference as well as diagnostic criteria for osteoporosis developed for postmenopausal Caucasian women. Many studies indicate that there are important racial differences in skeletal health and fracture risk, an observation that makes the application of Caucasian data to all groups problematical. This study was undertaken to establish a BMD referent database in Chinese American women and to compare it with a Caucasian female database. It is expected that a race-specific database will be useful in the assessment of bone health for Chinese American women.

METHODS

Healthy Chinese American women (n=359), ages 20-90, were recruited. Along with dual-energy X-ray absorptiometry (DXA) of the total hip and lumbar spine, demographic, medical, familial, nutritional, and behavioral data were obtained. The mean and standard deviation for BMD at each site was calculated for each 10-year age group and compared to mean BMD values for Caucasian women supplied as found in the Hologic DXA instrument. Osteoporosis diagnosis rates for this cohort, calculated with the Caucasian and newly established Chinese American BMD referent values, were compared with each other.

RESULTS

Compared with Caucasian women, Chinese American women have significantly lower BMD at the lumbar spine, total hip, and femoral neck across a wide spectrum of age groups. As a consequence, more than one-half of Chinese American women>or=50 years of age, who would be characterized as osteoporotic using a Caucasian referent, would not be diagnosed as such if a Chinese American referent were utilized.

CONCLUSION

Chinese American reference BMD values are significantly lower than those for Caucasian women. Future studies relating Chinese American BMD values to fracture risk are necessary in order to determine if ethnic database-derived T-scores would be more predictive of fracture risk and to develop meaningful diagnostic criteria for this population.

Bone mineral density reference norms for Hong Kong Chinese

The aim of this study was to establish bone mineral density (BMD) reference norms for Hong Kong Chinese using Hologic QDR 2000 and 4500 densitometers, and to estimate the prevalence of osteoporosis in the population. Altogether, 4,274 subjects (2,415 females and 1,859 males), aged 9-94 years old, were recruited using a combination of private solicitation and public advertising from schools, community centers, nursing homes, housing estates, and the general community in Hong Kong. Among females, BMD increased by 20% at the total hip and 48% at the lumbar spine between ages 10 and 20 but remained essentially constant between ages 20 and 40. Between ages 40 and 70, BMD declined by 17% at the total hip and 23% at the spine. Total hip BMD continued to drop after age 70 but little change in spine BMD was observed. Among males, BMD increased by 45% at the total hip and 77% at the spine between age 10 and 30. Between ages 30 and 80, total hip BMD decreased by 20%. Lumbar spine BMD decrease was milder, showing a loss of 4% between ages 30 to 50 and remaining relatively constant afterwards. The prevalence of osteoporosis was consistently overestimated when using Hologic-supplied Caucasian cutoffs as compared with local Chinese cutoffs. The prevalence of osteoporosis among Chinese women 50 years or older was 37% and 16% at the spine and total hip, respectively, while that among Chinese men 50 years or older was 7% and 6% at the spine and total hip, respectively. Prior studies have been limited by size or restricted to women. This study represents the largest sample of Hong Kong Chinese amassed to date, provides continuous BMD reference values from ages 10 to 85 for both women and men, and yields more reliable estimates of the prevalence of osteoporosis for the population.

Normative data of bone Mineral Density in healthy population of Tehran, Iran: a cross sectional study

Background

Osteoporosis is a major problem and is a hidden epidemic disease in the world. Early diagnosis by measurement of Bone Mineral Density (BMD) and treatment can prevent and reduce disease complications, especially fractures. As there is no comprehensive study in Iran, this study designed to assess BMD discrepancy in 20–69 yr Tehran population as well as prevalence of osteoporosis and osteopenia.

Methods

553 people (34% men, 66%women) from 50 Blocks in Tehran randomly selected. The assessment of BMD in spine and femur region performed through DXA method. All subjects clinically examined and their BMIs determined.

Results

The average spinal BMD score in men were more than in women. The peak bone mass of spine bone both in men and women occurred during 20–29 yr and reduction began from the age of 40. At the age of 60 to 69, loose of bone density was 19.6% in lumbar spine and 18.5% in femur of women and also 7.9% in lumbar spine and 14.6% in femur of men. Prevalence of osteoporosis in this age group in lumbar spine and femur was 32.4% and 5.9% in women and 9.4% and 3.1% in men respectively.

Conclusion

In all age groups, peak bone mass was lower than European or American population, whereas the rate of bone loss was as much as the some population and actually this process justifies the prevalence of osteoporosis and osteopenia in Tehran population.

Development of a clinical assessment tool in identifying Asian men with low bone mineral density and comparison of its usefulness to quantitative bone ultrasound

Osteoporosis in men is a largely neglected condition in Asia (and elsewhere), despite the fact that one-third of hip fractures occur in men. Moreover, access to bone mineral density (BMD) measurements is limited in many areas of Asia, and inexpensive methods of targeting high risk patients for BMD measurements would be valuable. We have developed a simple clinical assessment tool to identify high risk Asian men for BMD measurements. Information on risk factors was collected from 420 community-dwelling adult Chinese men aged 50 years and above using a structured questionnaire, and the ability of these risk factors to identify subjects with femoral neck BMD T score < or = -2.5 was assessed. Multiple regression analysis and item reduction yielded a final clinical risk assessment tool based on only age and weight, similar to the Osteoporosis Self-assessment Tool for Asians (OSTA), described previously for Asian women. The OSTA values of < or = -1 had a sensitivity of 81% and specificity of 66%, and the area under the receiver operating characteristics curve was 0.83. The index was validated in another sample of 356 men with a sensitivity of 82% and specificity of 67 %, and an AUC of 0.85. The usefulness of OSTA was further compared to calcaneal quantitative bone ultrasound (QUS) in the validation sample of 356 men. The optimal cutoff T score of -1.2 for QUS yielded sensitivity and specificity values of 75 and 67%, respectively. The AUC for QUS was 0.79. Combining OSTA and QUI gave a sensitivity of 88% and specificity of 66% to identify men with low BMD at the femoral neck, and an AUC of 0.86 which was statistically not different from either OSTA or QUI alone. We conclude that OSTA is a simple and effective clinical risk assessment tool for identifying not only female but also male subjects at increased risk of osteoporosis, and its use could facilitate the appropriate and more cost-effective use of bone densitometry in developing countries.

Osteoporosis in Chinese patients with anorexia nervosa

OBJECTIVE

A case-control study was conducted to determine whether bone mass is reduced in Chinese patients with anorexia nervosa (AN) and to study the risk factors for low bone mass in the same population.

METHOD

Bone mineral density (BMD) of the lumbar spine and hip was measured by dual-energy X-ray absorptiometry in 42 AN patients and 221 controls.

RESULTS

Patients with AN had a significantly lower BMD in the total hip and spine compared with controls (p <.001). In AN patients, linear regression showed that lowest body mass index (BMI) was positively associated with BMD in the hip (p = .04) whereas duration of illness was negatively associated with BMD in the hip (p = .05).

DISCUSSION

Chinese patients with AN are at risk of low BMD. Duration of illness and lowest BMI were significant predictors of reduced BMD in Chinese patients with AN.

Osteoporosis prevalence in men varies by the normative reference

Controversy surrounds which normative data should be used to estimate osteoporosis prevalence in men. Prevalence estimates may vary significantly when different normative standards are applied. Five normative datasets (NHANES female norms, local female norms, Hologic densitometer manufacturer female norms, NHANES male norms, Hologic male norms) were used to estimate the prevalence of osteoporosis by World Health Organization diagnostic criteria in a study population of 311 consecutive men between the age of 30 and 91 (mean 60.3 yr) referred to an outpatient osteoporosis center between January 1996 and December 1998. Statistically significant variations were seen in osteoporosis prevalence measured at three anatomical sites. The greatest relative variation was seen for the total femur, where osteoporosis prevalence ranged from 7.0% (NHANES and Hologic female norms) to 15.6% (NHANES male norms). The least relative variation was seen at the lumbar spine, where prevalence ranged from 18.1% (Hologic female norms) to 29.6% (local female norms). When considering osteoporosis at any site, prevalence was lowest (23.5%) based on Hologic female norms and highest (35.8%) based on local female norms. Interpretation of prevalence data should include an assessment of how normative standards influence reporting of the population at high risk of fracture.

Areal and volumetric bone density in Hong Kong Chinese: a comparison with Caucasians living in the United States

It is a common perception that Asians have lower bone density than Caucasians. However, such relationships could be confounded by bone size. In this study, the skeletal status of a convenience sample of 482 men and 887 women living in Hong Kong is compared with published data for Caucasians living in Rochester, Minnesota. Areal bone mineral density (BMD, g/cm(2)) and volumetric bone mineral apparent density (BMAD, g/cm(3)) were determined for the lumbar spine and proximal femur, using the Hologic QDR 2000 instrument. Cross-calibration was performed by measuring a common phantom, and the Hong Kong data were adjusted by a multiplication factor. Lumbar spine and femoral neck BMD and BMAD of Chinese men and women were all significantly lower ( P<0.001 by t-test) than those of Caucasians, but the differences in BMAD were on average only about half the size of the differences in BMD. For instance, in postmenopausal Chinese women, BMD at the femoral neck and lumbar spine were 15.2% and 18.8% lower respectively, but BMAD at the femoral neck and lumbar spine were only 7.8% and 12.4% lower respectively. Similar trends were observed in men. After adjusting for age, body height and weight, the difference in BMAD between Caucasians and Chinese was further reduced and only statistically significant among postmenopausal women and among men younger than age 50 years for the lumbar spine. For instance, the adjusted BMAD in postmenopausal Chinese women at the femoral neck and lumbar spine were 3.9% ( P=0.03 by ANCOVA) and 7.3% ( P<0.001 by ANCOVA) lower respectively, while the adjusted BMAD at the lumbar spine for Chinese men younger than 50 years was 11.7% lower ( P<0.01 by ANCOVA). Predictors of BMAD in Hong Kong Chinese women include body weight, age at menarche, cigarette smoking, and oral contraceptive use ( P<0.001), while body weight was the only independent predictor of BMAD in Hong Kong Chinese men ( P<0.001). We conclude that bone density is lower in Hong Kong Chinese men and women than in Caucasians, although such differences were attenuated by adjustments for bone size, body weight and height.

Epidemiology worldwide

Osteoporosis is a global problem that will increase in significance with the growing elderly population. The condition affects both sexes and all races, albeit to different degrees. This article reviews the epidemiology of osteoporosis as it relates to age, sex, ethnicity, and other risk factors and makes projections for the future as populations continue to age worldwide.