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

Volumetric Bone Mineral Density Measured by HR-pQCT in Patients with Psoriasis or Psoriatic Arthritis: A Systematic Review and Meta-Analysis with Trial Sequential Analysis

Bone health in psoriasis and psoriatic arthritis has been emphasized in recent years. Novel imaging modalities allow investigations into volumetric bone mineral density (vBMD) and bone microstructure in psoriatic patients. However, literature regarding vBMD measured by high-resolution peripheral quantitative computed tomography (HR-pQCT) is inconclusive. We conducted a systematic review and meta-analysis to evaluate vBMD in patients with psoriatic disease. We searched PubMed, EMBASE, Web of Science, and Cochrane Library for relevant observational studies. A random-effects meta-analysis with trial sequential analysis (TSA) was performed. The pooled mean difference (MD) and 95% confidence interval (CI) were calculated. Five studies with 780 patients were included. Patients with psoriatic disease showed a lower average vBMD than controls (MD -14.90; 95% CI -22.90 to -6.89; TSA-adjusted CI -23.77 to -6.03; I² = 41%). Trabecular vBMD and cortical vBMD results were inconclusive because of the small sample size. Patients recruited in Asia and those whose vBMD were measured at the distal radius exhibited a lower average vBMD than controls. Further research should clarify the association of psoriasis with bone microstructure and the underlying pathophysiology.

Intraoperative femoral condyle fracture in primary total knee arthroplasty - a case-control study in Asian population

PURPOSE

Intraoperative femoral condyle fracture is a significant but rarely reported complication during primary total knee arthroplasty (TKA). This is the first study to identify the incidence, risk factors, location and outcome of these fractures in an Asian population with modern posterior-stabilized (PS) TKA.

MATERIALS AND METHODS

We reviewed 2682 consecutive primary TKAs performed between 2011 and 2017 in a single centre; 23 femoral condyle fractures were identified and analysed.

RESULTS

Fractures were managed conservatively with screw fixation or revision arthroplasty. Mean follow up was 3.0 years (range 3 months to 5.9 years). All patients achieved bone union and good functional outcome. The mean Knee Society Knee score was 89.4 (range 71-100) and the function score was 80.2 (range 60-95) at a mean of 3.0 years post-operation. Bilateral surgery was found to be a significant risk factor for femoral condyle fracture, while there was a higher trend of fracture in female patients and Stryker articular surface mounted (ASM) navigation.

CONCLUSIONS

Intraoperative fracture is not uncommon with modern PS TKA. Postulated risk factors for fracture were discussed. Early identification of risk factors and a rigorous surgical technique may reduce risk of fracture. A good functional result was expected after proper treatment.

Total Hip Bone Area Affects Fracture Prediction With FRAX® in Canadian White Women

CONTEXT

Areal bone mineral density (BMD) measurements are confounded by skeletal size. Hip BMD is an input to the FRAX® tool (Centre for Metabolic Bone Diseases, University of Sheffield, United Kingdom), but it is unknown whether performance is affected by hip area.

OBJECTIVE

To examine whether fracture prediction by FRAX® is affected by hip area.

DESIGN AND SETTING

Cohort study using a population-based BMD registry.

PATIENTS

A total of 58,108 white women aged ≥40 years.

MAIN OUTCOME MEASURES

Incident major osteoporotic fracture (MOF; n = 4913) and hip fracture (n = 1369), stratified by total hip area quintile, before and after adjustment for hip axis length (HAL).

RESULTS

Smaller hip area was associated with younger age and lower FRAX® scores, whereas incident fractures were greater in those with larger hip area (P for trend < 0.001). Larger hip area quintile increased risk for MOF and hip fracture when adjusted for FRAX® score with BMD (P for trend < 0.001). Each standard deviation increase in hip area was associated with greater risk for incident MOF [adjusted hazard ratio (HR), 1.08; 95% confidence interval (CI), 1.05 to 1.11] and hip fracture (HR, 1.16; 95% CI, 1.11 to 1.21), but not after adjustment for HAL. FRAX® with BMD underestimated MOF risk in the largest hip area quintile and underestimated hip fracture risk in the three largest hip area quintiles.

CONCLUSIONS

In Canadian white women, skeletal size based on hip area affects fracture risk assessment based on FRAX® score with BMD, with risk underestimated in those with larger hip areas. Including HAL in the risk assessment compensates for this confounding by skeletal size and provides for more accurate assessment of fracture risk.

Differences in bone quality and strength between Asian and Caucasian young men

This is a cross-sectional study to assess differences in bone quality in young Asian and Caucasian (n = 30/group) men between 25 and 35 years. We found that Asians had smaller bones, thicker and denser cortices, and more plate-like trabeculae, but stiffness did not differ between groups.

INTRODUCTION

We conducted a cross-sectional study to assess differences in bone quality in young Asian and Caucasian (n = 30/group) men between 25 and 35 years.

METHODS

We measured bone mineral density (BMD) at the spine, total hip (TH), femoral neck (FN), and forearm by dual energy X-ray absorptiometry (DXA), and bone geometry, density, microarchitecture, and mechanical competence at the radius and tibia by high-resolution peripheral quantitative computed tomography (HR-pQCT) with application of individual trabecula segmentation (ITS) and trabecular and whole bone finite element analysis (FEA). We measured load-to-strength ratio to account for differences in bone size and height, respectively. We used Wilcoxon rank sum and generalized linear models adjusted for height, weight, and their interaction for comparisons.

RESULTS

Asians were 3.9 % shorter and weighed 6.5 % less than Caucasians. In adjusted models: by DXA, there were no significant race-based differences in areal BMD; by HR-pQCT, at the radius, Asians had smaller total and trabecular area (p = 0.003 for both), and denser (p = 0.01) and thicker (p = 0.04) cortices at the radius; by ITS, at the radius Asians, had more plate-like than rod-like trabeculae (PR ratio p = 0.01), greater plate trabecular surface (p = 0.009) and longer rod length (p = 0.002). There were no significant race-based differences in FEA or the load-to-strength ratio.

CONCLUSIONS

Asians had smaller bones, thicker and denser cortices, and more plate-like trabeculae, but biomechanical estimates of bone strength did not differ between groups. Studies are needed to determine whether these differences persist later in life.

New reference data on bone mineral density and the prevalence of osteoporosis in Korean adults aged 50 years or older: the Korea National Health and Nutrition Examination Survey 2008-2010

This cross-sectional study was performed to investigate the reference values for bone mineral density (BMD) measured by dual-energy X-ray absorptiometry (DXA) and the prevalence of osteoporosis in the Korean population by applying domestic reference data. In total, 25,043 Korean adults ≥20 yr of age (11,792 men and 13,251 women) participated in the study. The BMDs of the total hip, femoral neck, and lumbar spine were measured by DXA (Discovery-W, Hologic Inc.), and subjects with a BMD - 2.5 standard deviations or lower than the mean BMD for young adults (20-29 yr old) were considered to have osteoporosis. When applying the new reference values determined in this study from Korean subjects, the overall prevalence of osteoporosis increased in men aged ≥50 yr compared with that provided by the DXA manufacturer from Japanese subjects (12.2% vs. 7.8%, P<0.001) and decreased in postmenopausal women aged ≥50 yr (32.9% vs. 38.7%, P<0.001). According to the findings of this study, use of the reference values provided by the DXA manufacturer has resulted in the underdiagnosis of osteoporosis in Korean men and the overdiagnosis of osteoporosis in Korean women. Our data will serve as valuable reference standards for the diagnosis and management for osteoporosis in the Korean population.

Reference values of bone mineral density and prevalence of osteoporosis in Chinese adults

We pooled bone mineral density (BMD) data published in 91 articles including 139,912 Chinese adults and then established a national-wide BMD reference database at the lumbar spine and femur neck for Chinese adults. The prevalence of osteoporosis in the middle-aged and elderly Chinese population was also estimated.

INTRODUCTION

Well-accepted reference value of BMD is lacking in Chinese. We established the reference database and assessed osteoporosis prevalence based on published literature conducted in the Mainland China, Taiwan, and Hong Kong Chinese.

METHODS

We searched for all published articles indexed in MEDLINE, PubMed, CNKI, and SinoMed up to January 2013. We included cross-sectional studies that examined BMD using a dual-energy X-ray absorptiometry at the femur neck (FN) and/or lumbar spine (LS) in healthy adults. Overall age-specific mean (SD) BMD were pooled after standardization.

RESULTS

Ninety-one studies including 51,906 males and 88,006 females (≥ 20 years) in 38 cities in China were included in this pooling study. Gender- and age-specific reference curves of standardized BMD (sBMD) at the LS and FN were constructed. The sBMD cutoffs for osteoporosis classification were 0.746 and 0.549 in women, and 0.680 and 0.568 g/cm(2) in men; age-standardized prevalence of osteoporosis was 23.9 % and 12.5 % in women and 3.2 % and 5.3 % in men aged ≥ 50 years at the LS and FN, respectively. Meta-regression analysis showed that greater age and altitude, lower latitude, smaller city size, earlier detection time, and random sample were correlated to lower sBMD in at least one gender-specific bone sites; the Hologic DXA produced a higher value of FN sBMD than the other two devices (Lunar and Norland).

CONCLUSION

We have established a national-wide BMD reference database at the LS and FN for Chinese adults and estimated the prevalence of osteoporosis in the middle-aged and elderly Chinese population.

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.

Health Fair Report of Asian Americans in Michigan

There is little information about Asian American health in Michigan. This highlights an urgent need to collect their health data to understand and help this fastest growing ethnic group live healthier lives and reduce health disparities. Data for about 300 individuals attending two major health fairs were collected to study older Chinese and Vietnamese immigrants. The analyses show that they have high prevalence rates of hypertension, high cholesterol and diabetes, even though their body mass index is relatively low. The report of these analyses is a starting point to understand the study groups. Such data can help health care providers give sound advice to their patients and allow those of us in public health to design proper health programs that may benefit them. But more data is needed to include major Asian ethnic groups and identify common health concerns among all Asian Americans.

Racial/ethnic differences in bone mineral density among older women

The epidemiologic information regarding international differences in bone mineral density (BMD) in women is currently insufficient. We compared BMD in older women across five racial/ethnic groups in four countries. The femoral neck, total hip, and lumbar spine BMD were measured in women (aged 65-74 years) from the Study of Osteoporotic Fractures (SOF) (5,035 Caucasian women and 256 African American women in the US), the Tobago Women's Health Study (116 Afro-Caribbean women), the Ms Os Hong Kong Study (794 Hong Kong Chinese women) and the Namwon Study (1,377 South Korean women). BMD was corrected according to the cross-site calibration results for all scanners. When compared with US Caucasian women, the age adjusted mean BMD measurements at the hip sites were 21-31 % higher among Tobago Afro-Caribbean women and 13-23 % higher among African American women. The total hip and spine BMD values were 4-5 % lower among Hong Kong Chinese women and 4-7 % lower among South Korean women compared to US Caucasians. The femoral neck BMD was similar in Hong Kong Chinese women, but higher among South Korean women compared to US Caucasians. Current/past estrogen use was a significant contributing factor to the difference in BMD between US versus non-US women. Differences in body weight partially explained the difference in BMD between Asian versus non-Asian women. These findings show substantial racial/ethnic differences in BMD even within African or Asian origin individuals, and highlight the contributing role of body weight and estrogen use to the geographic and racial/ethnic variation in BMD.

Sex steroids and bone health in older Chinese men

This study examines the association between sex steroids, bone mineral density (BMD), and incident fractures in 1,489 community-living Chinese men aged 65 and over. Chinese men with low serum estradiol levels display elevated bone loss and increased risk of fractures similar to findings in Caucasians.

INTRODUCTION

This study examines the association between serum total testosterone (TT), free testosterone (free T), estradiol (E(2)), bioavailable estradiol (bioE(2)), sex hormone binding globulin (SHBG), BMD, and incident fractures.

METHODS

This is a cohort study with 4-year follow-up in the community in Hong Kong SAR, China. One thousand four hundred eighty-nine community-living Chinese men aged 65 and over participated. Sex steroid levels and BMD were measured at baseline; BMD was repeated after 4 years of follow-up, and fracture incidence from ascertainment from hospital databases was determined over 4 years of follow-up.

RESULTS

The strongest age-adjusted positive association with total hip and femoral neck BMD was with bioE(2), followed by E(2). Greater bone loss occurred in the lowest quartile of E(2) and bioE(2). The lowest quartile of free T and bioE(2) and the two highest quartile of SHBG were associated with the highest percentage of participants with incident fractures. Those in the lowest quartile of E(2) and bioE(2) had approximately a 50% increased risk of incident fractures compared with the other three quartiles. This relationship remains significant for nonvertebral incident fractures (hip, radius, pelvis, and humerus) for E(2) only, but not bioE(2). Compared with the group with the three highest quartiles of TT and E(2), the group with the lowest quartile of both had approximately twice the risk of nonvertebral osteoporosis-related incident fractures.

CONCLUSION

Chinese men with low serum estradiol levels display elevated bone loss and increased risk of fractures similar to findings in Caucasians.

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.

Race/ethnic differences in bone mineral densities in older men

SUMMARY

BMD was compared across race/ethnic groups. There were substantial race/ethnic differences in BMD even within African or Asian origin. Additional adjustment for body size greatly attenuated or reversed the differences between US Caucasian men vs Asian men. It illustrates the role of body size on the difference between these groups.

INTRODUCTION

There is insufficient epidemiologic information about men's bone mineral density (BMD) levels across race/ethnic groups and geographic locations.

METHODS

In a cross-sectional design, we compared BMD in older men across seven race/ethnic groups in four countries. Femoral neck, total hip, and lumbar spine BMD were measured in men (age 65 to 78 years) from the Osteoporotic Fractures in Men (MrOS) Study (4,074 Caucasian, 208 African-American, 157 Asian, and 116 Hispanic men in USA), Tobago Bone Health Study (422 Afro-Caribbean men), MrOS Hong Kong Study (1,747 Hong Kong Chinese men), and the Namwon Study (1,079 South Korean men). BMD was corrected according to the cross-site calibration results for all scanners.

RESULTS

When compared with US Caucasian men, Afro-Caribbean and African-American men had, respectively, 8-20% and 6-11% higher age-adjusted mean BMD at all three bone sites. Hip BMD was similar in US Caucasian and Hispanic men, US Asian, Hong Kong Chinese, and Korean men had 3-14% lower BMD at all bone sites except femoral neck in Korean men. Additional adjustment for weight and height greatly attenuated or reversed the differences between US Caucasian men vs Asian men including US Asian, Hong Kong Chinese, and South Korean men. Among Asian groups, Korean men had higher femoral neck BMD and lower total hip BMD.

CONCLUSION

These findings show substantial race/ethnic differences in BMD even within African or Asian origin and illustrate the important role of body size on the difference between Asian men and others.

Characteristics of age-related changes in bone compared between male and female reference Chinese populations in Hong Kong: a pQCT study

There have been few comprehensive studies on the age-related changes in bone mineral density (BMD) and bone structure in Chinese people. Using peripheral quantitative computed tomography (pQCT), we assessed volumetric BMD of both trabecular and cortical bone and their geometry at both radius and tibia in 620 Chinese men and 638 women, aged 20–98 years, in Hong Kong. Cortical BMD did not start declining until after the age of 50 years in women and the age of 60 years in men. In contrast, trabecular BMD declined with age starting from adulthood in both sexes, and the rates of decline accelerated after the age of 50 years only in women. The integral and trabecular bone area expanded with age in older men and women, primarily at the tibia. Cortical bone area decreased significantly in older women, particularly at the tibia, while it decreased only slightly with aging in men. The moment of inertia decreased with age at the radius in older men and women. At the tibia, age-related decline accelerated in older women, but not in older men. It was concluded that trabecularization of bone in response to declining BMD and mechanical loading may be maladaptive by reducing cortical bone area, if periosteal apposition cannot keep pace with it.

Evaluation of compressive strength index of the femoral neck in Caucasians and chinese

Compressive strength index (CSI) of the femoral neck is a parameter that integrates the information of bone mineral density (BMD), femoral neck width (FNW), and body weight. CSI is considered to have the potential to improve the performance of assessment for hip fracture risk. However, studies on CSI have been rare. In particular, few studies have evaluated the performance of CSI, in comparison with BMD, FNW, and bending geometry, for assessment of hip fracture risk. We studied two large populations, including 1683 unrelated U.S. Caucasians and 2758 unrelated Chinese adults. For all the study subjects, CSI, femoral neck BMD (FN_BMD), FNW, and bending geometry (section modulus [Z]) of the samples were obtained from dual-energy X-ray absorptiometry scans. We investigated the age-related trends of these bone phenotypes and potential sex and ethnic differences. We further evaluated the performance of these four phenotypes for assessment of hip fracture risk by logistic regression models. Chinese had significantly lower FN_BMD, FNW, and Z, but higher CSI than sex-matched Caucasians. Logistic regression analysis showed that higher CSI was significantly associated with lower risk of hip fracture, and the significance remained after adjusting for covariates of age, sex, and height. Each standard deviation (SD) increment in CSI was associated with odds ratios of 0.765 (95% confidence interval, 0.634, 0.992) and 0.724 (95% confidence interval, 0.569, 0.921) for hip fracture risk in Caucasians and Chinese, respectively. The higher CSI in Chinese may partially help explain the lower incidence of hip fractures in this population compared to Caucasians. Further studies in larger cohorts and/or longitudinal observations are necessary to confirm our findings.

The bare bones of race

In this paper I examine claims of racial difference in bone density and find that the use and definitions of race in medicine lack a theoretical foundation. My central argument is that the social produces the biological in a system of constant feedback between body and social experience. By providing a different angle of vision on claimed racial differences I hope to move the conversation away from an ultimately futile discussion of nature versus nurture, where time is held constant and place seen as irrelevant, and begin to build a new paradigm for examining the contributions of geographic ancestry, individual lifecycle experience, race, and gender to varied patterns of health and disease.

Utility of biochemical markers of bone turnover and bone mineral density in management of osteoporosis

Biochemical markers of bone turnover (bone-turnover markers) are released during bone formation or resorption and can be measured in blood and/or urine. The concentration of bone-turnover markers in serum or urine reflect bone remodeling activity and can potentially be used as surrogate markers of the rate of bone formation or bone resorption. While the diagnosis of osteoporosis is based on bone mineral density (BMD), the absolute fracture risk for a particular BMD measurement varies several fold depending on age and is also influenced by other clinical risk factors. The measurement of bone-turnover markers may be of additional value to BMD and clinical risk factors in fracture risk assessment by improving the sensitivity and specificity of prediction of future fractures. In clinical practice, bone-turnover markers may help make cost-effective treatment decisions in patients with borderline absolute risk. BMD changes following treatment cannot be detected with confidence for 12-24 months due to measurement imprecision. Bone-turnover markers, which show an early response following treatment, may be useful for monitoring therapy, identifying non-compliance and non-responders, and predicting early response to therapy. This review concludes by identifying the need for internationally agreed-upon standards for bone resorption and formation.

Menopausal symptom experience: an online forum study

AIM

The aim of the study was to explore the menopausal symptom experience of White midlife women.

BACKGROUND

Recent cross-cultural investigations have indicated important ethnic differences in menopausal symptoms and have challenged the universality of these symptoms. Currently available cultural knowledge on menopausal experience, however, is inadequate to guide appropriate and adequate care even for White women in the menopausal transition.

METHOD

A cross-sectional qualitative online forum study was conducted in 2007 with 23 midlife women who self-identified as non-Hispanic Whites using convenience sampling. Seven topics related to menopausal symptom experience were used to guide the online forum for 6 months. The data were analysed using thematic analysis.

RESULTS

The experiences of menopause caused women to redefine themselves within their busy daily life schedules. They were optimistic about their symptoms, and tried to laugh at the experience to boost their inner strength and motivate themselves to persevere. Many thought that both generational and life-style differences were much more important than ethnic differences in menopausal symptom experiences. In seeking assistance with the symptoms of menopause, women were not satisfied with the guidance of their physicians.

CONCLUSION

Nurses need to listen carefully to what women themselves say about their own experiences with menopausal symptoms and avoid imposing predetermined symptom management strategies. Further studies of women's perceptions of life-style influences are needed to guide symptom management. In addition, studies of generational changes in menopausal symptom experience are needed.

Soybean and soy isoflavone intake indicate a positive change in bone mineral density for 2 years in young Korean women

Many studies have shown that soybean and isoflavones have a favorable effect on bone mass for postmenopausal women, but few data are available on young Asian women. To investigate the effect of soybean and isoflavone intake on bone mineral density (BMD) and its change among young Korean women over 2 years, we conducted a longitudinal study for 34 women. The BMD was measured 3 times with 1-year intervals by dual x-ray absorptiometry at the lumbar spine and femur (neck, Ward's triangle [WT], and trochanter). Dietary intake was assessed up to 8 times by 24-hour recall with average 4-month interval. During the study period, BMD increased significantly for lumber spine and WT (2.5% and 5.2%). The average daily intake of soybeans and isoflavones was 39 g and 8 mg, respectively. Soybean intake and total isoflavone intake had positive correlation on femoral neck (FN) and WT. By longitudinal mixed-model regression analysis, BMD increased 0.26% per 1 mg of isoflavone intake per year in the FN and 0.31% for WT (P = .05 and .008). In conclusion, soybean and isoflavone intake have a positive effect on the change of BMD on the FN and WT among young Korean women. Because soybean and isoflavone intakes could be confounded by other nutrients, the positive effects of isoflavones on bone should be further investigated.

Race and ethnic variation in proximal femur structure and BMD among older men

Femoral neck dimensions and vBMD from QCT were compared among 3,305 black, Asian, Hispanic, and white men >or=65 yr of age. All had similar stature-adjusted mean femoral neck volume, but black and Asian men had thicker cortices and higher trabecular vBMD, which may increase bone strength.

INTRODUCTION

Hip fracture rates among elderly U.S. black and Asian men are lower than rates among white men. Structural characteristics or volumetric BMD (vBMD), which confer advantages for femoral neck bone strength, may vary by race/ethnicity. However, this topic has not been studied in detail.

MATERIALS AND METHODS

In a cross-sectional study, dimensions and vBMD in the femoral neck and shaft were obtained from QCT scans among 3,305 men >or=65 yr of age in the Osteoporotic Fractures in Men (MrOS) study. Femoral neck measures were cross-sectional area; integral, cortical, and medullary volumes and integral, cortical, and trabecular vBMD. Shaft measures were cross-sectional, cortical, and medullary areas and cortical vBMD. Self-reported race/ethnicity was classified as black, Asian, Hispanic, or white. We used multivariable linear regression models with adjustment for age, height, and body mass index to compare means of the outcome measures in black, Asian, and Hispanic men to those in whites.

RESULTS

All groups had similar femoral neck integral volume. Among black and Asian men, mean cortical volume as a percent of integral volume was 6% greater, integral vBMD was 6-10% greater, and trabecular vBMD was 33-36% greater than means among whites. Shaft cross-sectional area was similar among blacks, but smaller among Asians, compared with whites. However, mean shaft cortical area was greater among blacks but similar among Asians and whites, resulting in mean cortical thickness being 5% greater among black and Asian men. Blacks also had greater mean cortical vBMD in both the femoral neck and shaft.

CONCLUSIONS

Black and Asian men >or=65 yr of age have features in the proximal femur that may confer advantages for bone strength. Specifically, greater cortical thickness and higher trabecular vBMD among black and Asian men could help explain the lower hip fracture rates in these populations. Discerning the mechanisms underlying these differences could provide advances for the prevention and treatment of osteoporosis.

Differences in bone mineral status between urban and rural Chinese men and women

BACKGROUND

Few studies have investigated differences in bone health and associated lifestyle factors between urban and rural populations in countries, such as China, undergoing rapid nutrition transition. Such a study may help to identify risk factors of osteoporosis and provide evidence for future preventive strategies.

OBJECTIVE

To determine primarily whether differences in bone mineral content (BMC) and bone mineral density (BMD) exist between urban and rural Chinese men and women and secondly whether any urban-rural differences could be explained by body size or lifestyle factors.

METHODS

In total, 490 men and 689 women aged 50-70 were included in the study. 535 of them were from urban Shanghai and 644 from surrounding rural areas. Anthropometric measurements were conducted and spine lumber 1-4 BMC measurements were determined by dual-energy X-ray absorptiometry (DEXA). Information on socioeconomic status, medical history, smoking and drinking habits and physical activity were collected.

RESULTS

Urban men and women had significantly higher spine BMC, BMD and bone area than their rural counterparts (P<0.01). After controlling body size, the differences between urban-rural spine BMC and BMD remained in women (P<0.001), but were no longer significant in men. The urban and rural differences of BMC and BMD in women could not be explained by including the lifestyle factors such as income, intake of milk, vitamin D and calcium, total physical activity level, walking and social activity.

CONCLUSION

This study found the significant differences in both spine BMC and BMD between urban and rural men and women in Shanghai, China. This difference could be explained by the body size in men; however, it remained unexplained in women after adjusting for body size and certain lifestyle risk factors.

Combined hormonal contraception and bone health: a systematic review

This systematic review examined whether women who use combined hormonal contraception experience changes in risk of fracture or bone mineral density (BMD) that differ from nonusers. We identified 86 articles from PubMed and EMBASE (published 1966 to August 2005) that reported on fracture or BMD outcomes by use of combined hormonal contraceptives. The evidence relating to combined oral contraceptives (COCs) and fracture is inconclusive, as results from the available studies conflict. Studies of adolescent and young adult women generally found lower BMD among COC users than nonusers. Evidence for premenopausal adult women suggested no differences in BMD between COC users and nonusers. COC use in perimenopausal and postmenopausal women preserved bone mass, while nonusers lost BMD, but BMD among former COC users in this age group was the same as for never-users. Evidence for other combined hormonal methods was very limited, with one study indicating no effect of combined hormonal injectable use among premenopausal women on BMD and one study suggesting lower BMD among premenopausal users of the NuvaRing than in nonusers.

Adaptation of the Carter method to adjust lumbar spine bone mineral content for age and body size: application to children who were born preterm

In adults, the Carter method allows the separation of the lumbar spine bone mineral content (BMC) into its constituents; bone volume (BV) and volumetric density (bone mineral apparent density [BMAD]). However, this method is not widely used in pediatric studies and does not account for the effects of body habitus on bone mass. The aims of this study were to modify the Carter method for use in children by developing an approach that adjusts separately for age and body height, and to test whether lumbar spine bone mass is normal in children born who were born preterm. Twenty-five preterm-born children were matched to a term-born child. Lumbar spine bone mass was measured using dual-energy X-ray absorptiometry. The BV and BMAD were calculated. Z-scores based on age and height were calculated. The preterm group had reduced absolute height, weight, BMC, BV, and BMAD, and reduced height, weight, and BMC for their age. The BMC was appropriate for height. The BV was appropriate for age. The BMAD was reduced for age but appropriate for height. In preterm children, the major abnormality at the lumbar spine is a decrease in volumetric density; however, this decrease is proportional with their reduced stature, and we speculate that there is no reduction in the strength of the lumbar spine.

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.

Cross-calibration and minimum precision standards for dual-energy X-ray absorptiometry: the 2005 ISCD Official Positions

The International Society for Clinical Densitometry (ISCD) Committee on Standards of Bone Measurement (CSBM) consists of experts in technical aspects of bone densitometry. The CSBM recently reviewed the scientific literature on cross-calibration and precision assessment. A report with recommendations was presented at the 2005 ISCD Position Development Conference (PDC). Based on a thorough review of the data by the ISCD Expert Panel during the conference, the ISCD adopted Official Positions with respect to (1) cross-calibration when changing or replacing hardware; (2) the approach to cross-calibration when an entire system is changed to one made by either the same or a different manufacturer; (3) when no cross-calibration study or bone mineral density (BMD) comparison is done between facilities; and (4) the minimum acceptable precision for an individual technologist. We present here the ISCD Official Positions on these topics that were established as a result of the 2005 PDC, together with the associated rationales and supportive evidence.

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.

Bone status of Indian women from a low-income group and its relationship to the nutritional status

Indian women from low-income groups consume diets that have inadequate calcium coupled with too few calories, proteins and micronutrients. Hospital-based data suggest that these women have osteoporotic hip fractures at a much earlier age than Western women. Studies reporting bone parameters of the Indian population involving large sample sizes are not available. This study was therefore carried out with 289 women in the 30-60-year age group to estimate the prevalence of osteoporosis and measure the bone parameters by dual energy X-ray absorptiometry (DXA). Their mean (+/- SD) age was 41.0+/-8.60 years. Their mean (+/- SD) height, weight and body mass index (BMI) were 149.1+/-5.49 cm, 49.2+/-9.85 kg and 22.1+/-3.99, respectively. Dietary intake of calcium was estimated to be 270+/-57 mg/day. The prevalence of osteoporosis at the femoral neck was around 29%. Bone mineral density (BMD) and T scores at all the skeletal sites were much lower than the values reported from the developed countries and were indicative of a high prevalence of osteopenia and osteoporosis. BMD showed a decline after the age of 35 years in cases of the lumbar spine and femoral neck. This was largely due to a decrease of bone mineral content (BMC). The nutritional status of women appears to be an important determinant of bone parameters. BMD and BMC at all the skeletal sites and whole body increased significantly with increasing body weight and BMI of women (P<0.05). However, bone area (BA) did not change with an increase in BMI. In the multiple regression analysis, apart from body weight, age, menopause and calcium intake were the other important determinants of BMD (P<0.05). In addition to these, height was also an important determinant of WB-BMC. This study highlights the urgent need for measures to improve the nutritional status, dietary calcium intake and thus the bone health of this population.

Bone mineral density in ethnic Norwegians and Pakistani immigrants living in Oslo--The Oslo Health Study

Bone mineral density (BMD, grams per square centimeter) is scarcely studied in immigrants from the Indian subcontinent. Pakistani immigrants in Oslo, Norway, have a very high prevalence of vitamin D deficiency. Thus, it is of great interest to compare BMD between Pakistani immigrants and ethnic Norwegians in Oslo. The comparison was done with and without adjustment for skeletal size, and we examined whether known risk factors explained possible differences in bone density between these two ethnic groups. BMD was measured at the distal and ultra-distal forearm site in a random sample of the participants in the Oslo Health Study by single energy X-ray absorptiometry (SXA). One hundred and seventy-three Pakistani-born subjects (71 women, 102 men) and 1,386 Norwegian-born subjects (675 women, 711 men) aged 30, 40, 45 and 59/60 years, living in Oslo, were included in the analysis. To account for variation in skeletal size, we computed height-adjusted BMD values, BMD/height (grams per cubic centimeter), and volumetric bone mineral apparent density (BMAD, grams per cubic centimeter). We found no differences in distal or ultra-distal forearm BMD between Pakistanis and Norwegians in either women or men. We found, however, higher values in Pakistani men when BMD was height-adjusted (2% higher in distal sites and 5% in ultra-distal sites). We also found higher bone mass values (both distal and ultra-distal) in Pakistani women and men than in their Norwegian counterparts when volumetric measures, such as BMD/height (7%-8% higher in women, 6%-7% in men) and BMAD (6% higher in women, 8% in men), were used. In a regression model that included ethnicity, anthropometry and lifestyle factors, BMD was higher in Pakistani men than in Norwegian men, but not in women. We conclude that Pakistanis living in Oslo have similar BMD to ethnic Norwegians, but they have higher volumetric bone mass values. When we adjusted for confounders we found higher BMD values in Pakistani men than in Norwegian men.

Do young New Zealand Pacific Island and European children differ in bone size or bone mineral?

Although Pacific Island adults have been shown to have larger bones and greater bone mineral density than caucasians, no previous studies have been undertaken to determine whether differences are present in prepubertal children. Forty-one Pacific Island children (both parents of Pacific Island descent) and 38 European children, aged 3 to 7 years, living in New Zealand were studied. Heights and weights were determined by simple anthropometry and body mass index (BMI, kg/m2) was calculated. Body composition, bone size, and bone mineral content (BMC, g) were measured by dual energy X-ray absorptiometry (DXA) of the total body and the non-dominant forearm. Compared to European children, in data adjusted for age and gender, Pacific Island children had significantly greater (P < 0.05) BMC in the total body (12%), the ultradistal radius (16%), and the 33% radius (8%), and also greater total body bone area (10%). Bone mineral density (BMD, g/cm2) was higher only at the ultradistal radius (11%). However, after adjustment for body weight, in particular lean mass, no differences were seen between Pacific Island and European children in any bone measure. The larger bone area and BMC of young Pacific Island children can be explained by their greater height and weight. Therefore, this study has shown that prepubertal Pacific Island children do not have greater bone size or BMC for their weight.