Fracture prediction from FRAX for Canadian ethnic groups: a registry-based cohort study

We identified large between-ethnicity calibration differences in the Canadian FRAX® tool which substantially overestimated the major osteoporotic fracture (MOF) risk in Asian women and Black women, and overestimated hip fracture risk in Asian women.

PURPOSE

FRAX® is calibrated using population-specific fracture and mortality data. The need for FRAX to accommodate ethnic diversity within a country is uncertain. We addressed this question using the population-based Manitoba Bone Mineral Density (BMD) Program registry and self-reported ethnicity.

METHODS

The study population was women aged 40 years or older with baseline FRAX assessments (Canadian and other ethnic calculators), fracture outcomes, and self-reported ethnicity (White N = 68,907 [referent], Asian N = 1910, Black N = 356). Adjusted hazard ratios (HR) with 95% confidence intervals (CI) for time to MOF and hip fracture were estimated. We examined candidate variables from DXA that might contribute to ethnic differences including skeletal size, hip axis length (HAL), trabecular bone score (TBS), and estimated body composition.

RESULTS

Adjusted for baseline risk using the Canadian FRAX tool with BMD, Asian women compared with White women were at much lower risk for MOF (HR 0.46, 95% CI 0.35-0.59) and hip fracture (0.16, 95% CI 0.08-0.34). Black women were also at lower MOF risk (HR 0.58, 95% CI 0.32-1.00); there were no hip fractures. The US ethnic-specific FRAX calculators accounted for most of the between-ethnicity differences in MOF risk (86% for Asian, 92% for Black) but only partially accounted for lower hip fracture risk in Asian women (40%). The candidate variables explained only a minority of the effect of ethnicity. Gradient of risk in analyses was similar (p-interactions ethnicity*FRAX non-significant).

CONCLUSIONS

We identified significant ethnic differences in performance of the Canadian FRAX tool with fracture probability overestimated among Asian and Black women. The US ethnic calculators helped to address this discrepancy for MOF risk assessment, but not for hip fracture risk among Asian women.

Hip fractures in Singapore: ethnic differences and temporal trends in the new millennium

Despite an increase in absolute numbers, the age-standardized incidence of hip fractures in Singapore declined in the period 2000 to 2017. Among the three major ethnic groups, Chinese women had the highest fracture rates but were the only group to show a temporal decline.

INTRODUCTION

A study published in 2001 predicted a 30-50% increase in Singapore hip fracture incidence rates over the ensuing 30 years. To test that prediction, we examined the incidence of hip fracture in Singapore from 2000 to 2017.

METHODS

We carried out a population-based study of hip fractures among Singapore residents aged ≥ 50 years. National medical insurance claims data were used to identify admissions with a primary discharge diagnosis of hip fracture. Age-adjusted rates, based on the age distribution of the Singapore population of 2000, were analyzed separately by sex and ethnicity (Chinese, Malay, or Indian).

RESULTS

Over the 18-year study period, 36,082 first hip fractures were recorded. Total hip fracture admissions increased from 1487 to 2729 fractures/year in the years 2000 to 2017. Despite this absolute increase, age-adjusted fracture rates declined, with an average annual change of - 4.3 (95% CI - 5.0, - 3.5) and - 1.1 (95% CI - 1.7, - 0.5) fractures/100,000/year for women and men respectively. Chinese women had 1.4- and 1.9-fold higher age-adjusted rates than Malay and Indian women: 264 (95% CI 260, 267) versus 185 (95% CI 176, 193) and 141 (95% CI 132, 150) fractures/100,000/year, respectively. Despite their higher fracture rates, Chinese women were the only ethnic group exhibiting a decline, most evident in those ≥ 85 years, in age-adjusted fracture rate of - 5.3 (95% CI - 6.0, - 4.5) fractures/100,000/year.

CONCLUSION

Although the absolute number of fractures increased, steep drops in elderly Chinese women drove a reduction in overall age-adjusted hip fracture rates. Increases in the older population will lead to a rise in total number of hip fractures, requiring budgetary planning and new preventive strategies.

Relationship of American Indian blood quantum with osteoporosis risk: a cross-sectional study of American Indian women in Oklahoma

Information regarding the prevalence and risk of osteoporosis among American Indian (AI) women is limited. This study showed that with increasing AI blood quantum, the prevalence of osteoporosis at the hip based on BMD T-scores decreased and this appeared to be independent of other risk factors.

INTRODUCTION

This study was designed to investigate the effects of AI blood quantum (BQ) on osteoporosis prevalence and risk in a cohort of AI women in Oklahoma.

METHODS

Women (n = 301), aged 50 years and older, were recruited to participate in the Oklahoma American Indian Women's Osteoporosis Study. Baseline bone density, fracture history, bone biochemical markers, and potential risk factors were assessed. Participants were stratified by AI BQ into BQ1 ≤ 25%, BQ2 = 25-49%, BQ3 = 50-74%, and BQ4 = 75-100%. The effects of BQ on the prevalence and risk of osteoporosis were evaluated.

RESULTS

Based on T-scores, one in approximately eight women in the study was osteoporotic at one or more sites. The prevalence of osteoporosis decreased (p < 0.05) with increasing BQ, especially at the hip, trochanteric, and intertrochanter regions. No differences in bone-specific alkaline phosphatase and C-telopeptide were observed across BQ that could account for the differences in bone density. 25-OH vitamin D decreased with increasing BQ, but mean for each BQ1-4 was > 40 ng/mL. Fracture history did not differ across BQ, and though 52% of the population consumed less than the RDA for calcium, no effect of BQ was observed.

CONCLUSIONS

In this cohort of women who identified as AI, greater Indian BQ was associated with a decrease in the prevalence of osteoporosis.

Volumetric bone mineral density of the spine predicts mortality in African-American men with type 2 diabetes

The study showed that in African-American men with type 2 diabetes mellitus (T2D), vertebral volumetric bone mineral density (vBMD) predicts all-cause mortality, independent of other risk factors for death.

INTRODUCTION

Compared to European Americans, African Americans have lower rates of osteoporosis and higher rates of T2D. The relationships between BMD and fractures with mortality are unknown in this population. The aim of this study was to determine relationships between vertebral fractures and vertebral vBMD and mortality in African Americans with T2D.

METHODS

Associations between vertebral fractures and vBMD with all-cause mortality were examined in 675 participants with T2D (391 women and 284 men) in the African American-Diabetes Heart Study (AA-DHS). Lumbar and thoracic vBMD were measured using quantitative computed tomography (QCT). Vertebral fractures were assessed on sagittal CT images. Associations of vertebral fractures and vBMD with all-cause mortality were determined in sex-stratified analyses and in the full sample. Covariates in a minimally adjusted model included age, sex, BMI, smoking, and alcohol use; the full model was adjusted for those variables plus cardiovascular disease, hypertension, coronary artery calcified plaque, hormone replacement therapy (women), African ancestry proportion, and eGFR.

RESULTS

After mean 7.6 ± 1.8-year follow-up, 59 (15.1%) of women and 58 (20.4%) of men died. In men, vBMD was inversely associated with mortality in the fully adjusted model: lumbar hazard ratio (HR) per standard deviation (SD) = 0.70 (95% CI 0.52-0.95, p = 0.02) and thoracic HR per SD = 0.71 (95% CI 0.54-0.92, p = 0.01). Only trends toward association between vBMD and mortality were observed in the combined sample of men and women, as significant associations were absent in women. Vertebral fractures were not associated with mortality in either sex.

CONCLUSIONS

Lower vBMD was associated with increased all-cause mortality in African-American men with T2D, independent of other risk factors for mortality including subclinical atherosclerosis.

Association of trabecular bone score (TBS) and prior fracture differs among minorities in NHANES 2005-2008

The study investigates the association of trabecular bone score (TBS) and fractures among minority populations. In NHANES 2005-2008, TBS was associated with history of fractures in Caucasian subjects but demonstrated somewhat weaker associations in African American and Mexican American women.

INTRODUCTION

Trabecular bone score (TBS), a textural analysis of the lumbar spine DXA image, predicts fractures well in Caucasian (CA) and Asian populations but is less well studied in African American (AA) and Mexican American (MA) subjects. It is not clear whether TBS is associated with or is predictive of fragility in these racial/ethnic groups.

METHODS

We analyzed data from subjects from NHANES 2005-2008 over the age of 40 who had TBS: 1178 CA, 467 AA, and 397 MA women and 1200 CA, 502 AA, and 386 MA men. TBS was categorized into normal, ≥ 1.310, partially degraded < 1.310, and > 1.230, or degraded, ≤ 1.230. History of fracture was assessed by questionnaire.

RESULTS

Among women, there was an increasing prevalence of fracture with worsening TBS category. However, when controlling for age, BMI, and low T-score, the association between TBS category and previous fracture was only significant in CA women (OR 1.49 per worsening category, 95% CI 1.20-1.85). In men, there was also an increase in the prevalence of fracture with worsening TBS category in all races/ethnicities. When controlling for age, BMI, and low T-score, the association between TBS category and previous fracture was only significant in CA men (OR 1.47 per worsening category, 95% CI 1.10-1.95), though analysis was somewhat limited by small fracture numbers.

CONCLUSIONS

The association of fracture and TBS varies by race/ethnicity and gender with weaker association observed in AA and MA women. More research is needed to define the proper use of TBS for predicting fractures in minority groups.

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.

Worldwide Fracture Prediction

The substantial increase in the burden of non-communicable diseases in general and osteoporosis in particular, necessitates the establishment of efficient and targeted diagnosis and treatment strategies. This chapter reviews and compares different tools for osteoporosis screening and diagnosis; it also provides an overview of different treatment guidelines adopted by countries worldwide. While access to dual-energy X-ray absorptiometry to measure bone mineral density (BMD) is limited in most areas in the world, the introduction of risk calculators that combine risk factors, with or without BMD, have resulted in a paradigm shift in osteoporosis screening and management. To-date, forty eight risk assessment tools that allow risk stratification of patients are available, however only few are externally validated and tested in a population-based setting. These include Osteoporosis Self-Assessment Tool; Osteoporosis Risk Assessment Instrument; Simple Calculated Osteoporosis Risk Estimation; Canadian Association of Radiologists and Osteoporosis Canada calculator; Fracture Risk Assessment Calculator (FRAX); Garvan; and QFracture. These tools vary in the number of risk factors incorporated. We present a detailed analysis of the development, characteristics, validation, performance, advantages and limitations of these tools. The World Health Organization proposes a dual-energy X-ray absorptiometry-BMD T-score ≤ -2.5 as an operational diagnostic threshold for osteoporosis, and many countries have also adopted this cut-off as an intervention threshold in their treatment guidelines. With the introduction of the new fracture assessment calculators, many countries chose to include fracture risk as one of the major criteria to initiate osteoporosis treatment. Of the 52 national guidelines identified in 36 countries, 30 included FRAX derived risk in their intervention threshold and 22 were non-FRAX based.  No universal tool or guideline approach will address the needs of all countries worldwide.  Osteoporosis screening and management guidelines are best tailored according to the needs and resources of individual counties. While few countries have succeeded in generating valuable epidemiological data on osteoporotic fractures, to validate their risk calculators and base their guidelines, many have yet to find the resources to assess variations and secular trends in fractures, the performance of various calculators, and ultimately adopt the most convenient care pathway algorithms.

Ethnic Differences in Trabecular Bone Score

Trabecular bone score (TBS), a noninvasive textural analysis of the lumbar spine dual-energy X-ray absorptiometry (DXA) image, has been shown to predict fractures in Caucasian (CA) populations but has not been thoroughly studied in African-American (AA) populations. The aim of this study was to compare the TBS in AAs and CAs and to assess whether TBS can be used to refine fracture risk stratification in AA patients. Eight hundred twenty-five women (390 AAs, 435 CAs) referred for bone mineral density (BMD) as part of their clinical care had measurements of the TBS, the BMD of the lumbar spine, total hip, and femoral neck, and vertebral fracture assessment for detection of vertebral fractures. Unadjusted TBS was higher in CA than AA (1.275 vs 1.238, p < 0.001), but this was no longer true after adjusting for age and tissue thickness. Interestingly, differences in TBS were still highly significant in those under 60 yr of age even with adjustment for tissue thickness, but not in older subjects. There were 74 CAs and 56 AAs with vertebral fractures on vertebral fracture assessment (17% vs 14%, p = 0.30). In CA, the odds ratio (OR) for prevalent vertebral fracture per SD decrease in TBS was 2.33 (p < 0.001), whereas in AA, the OR was 1.43 (p = 0.02). In a multivariate logistic regression model that also included age, BMD T-score, and glucocorticoid use, the association between TBS and prevalent vertebral fractures was still highly significant in CAs (OR 1.54, p = 0.008) but not in AAs (OR 1.23, p = 0.21). Our results suggest that TBS may be less discriminatory in regard to fracture risk in AAs than in CAs and that TBS may need to be used differently in these 2 ethnic groups.

Ethnic Differences in Osteoporosis After Cardiac Transplantation

Cardiac transplantation is associated with a high risk of fracture. African Americans (AAs) are believed to have a lower risk of osteoporosis than Caucasians, but it is not clear whether they are also protected from osteoporosis resulting from the use of glucocorticoids and/or organ transplantation. We examined possible ethnic differences in 33 cardiac transplant recipients (16 AAs) in a cross-sectional analysis. In addition to bone mineral density and vertebral fracture assessment, we also compared biochemical variables, trabecular bone score, total body dual-energy X-ray absorptiometry, and disability. Overall fracture rates were low in both groups, with only 6 total subjects with fractures on vertebral fracture assessment or history of fracture. While T-scores were similar between groups, Z-scores were lower in AA with the difference reaching statistical significance when controlling for important covariates. The trabecular bone score was also lower in AAs than in Caucasians even when adjusting for age and tissue thickness (1.198 ± 0.140 vs 1.312 ± 0.140, p = 0.03). While AAs are generally thought to be protected from osteoporosis, our study instead suggests that AAs may be at higher risk of bone deterioration after cardiac transplantation and may need to be managed more aggressively than suggested by current guidelines.

Applying ethnic-specific bone mineral density T-scores to Chinese women in the USA

Caucasian reference data are used to classify bone mineral density in US women of all races. However, use of Chinese American reference data yields lower osteoporosis prevalence in Chinese women. The reduction in osteoporosis labeling may be relevant for younger Chinese women at low fracture risk.

INTRODUCTION

Caucasian reference data are used for osteoporosis classification in US postmenopausal women regardless of race, including Asians who tend to have lower bone mineral density (BMD) than women of white race. This study examines BMD classification by ethnic T-scores for Chinese women.

METHODS

Using BMD data in a Northern California healthcare population, Chinese women aged 50-79 years were compared to age-matched white women (1:5 ratio), with femoral neck (FN), total hip (TH), and lumbar spine (LS) T-scores calculated using Caucasian versus Chinese American reference data.

RESULTS

Comparing 4039 Chinese and 20,195 white women (44.8 % age 50-59 years, 37.5 % age 60-69 years, 17.7 % age 70-79 years), Chinese women had lower BMD T-scores at the FN, TH, and LS (median T-score 0.29-0.72 units lower across age groups, p < 0.001) using Caucasian reference data. Using Chinese American BMD reference data resulted in an average +0.47, +0.36, and +0.48 units higher FN, TH, and LS T-scores, respectively, reducing the prevalence of osteoporosis (T-score ≤ -2.5) in Chinese women at the FN (16.7 to 6.6 %), TH (9.8 to 3.2 %), and LS (23.2 to 8.9 %); osteoporosis prevalence at any one of three sites fell from 29.6 to 12.6 % (22.4 to 8.1 % for age 50-64 years and 43.2 to 21.0 % for age 65-79 years).

CONCLUSION

Use of Chinese American BMD reference data yields higher (ethnic) T-scores by 0.4-0.5 units, with a large proportion of Chinese women reclassified from osteoporosis to osteopenia. The reduction in osteoporosis labeling with ethnic T-scores may be relevant for younger Chinese women at low fracture risk.

FRAX updates 2016

PURPOSE OF REVIEW

In the 8 years since the launch of the FRAX tool, it has continued to grow with the addition of new country or territory models. Although the core of the fracture risk algorithm remains unchanged, there is growing evidence of possible additional independent clinical variables that might modulate the interpretation of the FRAX outputs. There is also an expanding number of international guidelines that incorporate FRAX assessments, leading to discussions on the use of FRAX in treated patients and the determination of intervention thresholds.

RECENT FINDINGS

This review encompasses recent information on the use of FRAX in immigrant populations and the potential influence of skeletal and extraskeletal risk factors on FRAX estimations. For example, trabecular bone score and falls risk appear to be promising additional factors in individual risk assessment. FRAX appears to remain accurate in those on osteoporosis treatments, but FRAX is not a suitable tool for use in treat-to-target strategies.

SUMMARY

The assessment of fracture risk in immigrants is probably more accurate with the use of the FRAX tool for the country of origin, if available. The impact of additional risk variables will need evaluation of the impact of these on recharacterizing patients by moving them across intervention thresholds.

A biomechanical sorting of clinical risk factors affecting osteoporotic hip fracture

Osteoporotic fracture has been found associated with many clinical risk factors, and the associations have been explored dominantly by evidence-based and case-control approaches. The major challenges emerging from the studies are the large number of the risk factors, the difficulty in quantification, the incomplete list, and the interdependence of the risk factors. A biomechanical sorting of the risk factors may shed lights on resolving the above issues. Based on the definition of load-strength ratio (LSR), we first identified the four biomechanical variables determining fracture risk, i.e., the risk of fall, impact force, bone quality, and bone geometry. Then, we explored the links between the FRAX clinical risk factors and the biomechanical variables by looking for evidences in the literature. To accurately assess fracture risk, none of the four biomechanical variables can be ignored and their values must be subject-specific. A clinical risk factor contributes to osteoporotic fracture by affecting one or more of the biomechanical variables. A biomechanical variable represents the integral effect from all the clinical risk factors linked to the variable. The clinical risk factors in FRAX mostly stand for bone quality. The other three biomechanical variables are not adequately represented by the clinical risk factors. From the biomechanical viewpoint, most clinical risk factors are interdependent to each other as they affect the same biomechanical variable(s). As biomechanical variables must be expressed in numbers before their use in calculating LSR, the numerical value of a biomechanical variable can be used as a gauge of the linked clinical risk factors to measure their integral effect on fracture risk, which may be more efficient than to study each individual risk factor.

Is the Swedish FRAX model appropriate for Swedish immigrants?

The incidence of hip fracture in Sweden is substantially lower in immigrants than in the population born in Sweden. Thus, the use of a FRAX® model in immigrants overestimates the risk of fracture, and the use of country of origin-specific models may be more appropriate.

INTRODUCTION

Age-specific fracture and mortality rates vary between countries so that FRAX tools are country-specific. In the case of immigrants, it is not known whether the model for the original or the new country is most appropriate. The aim of this study was to compare the incidence of hip fractures in foreign-born and Swedish-born individuals residing in Sweden.

METHODS

We studied the incidence of hip fracture in all men and women aged 50 years or more in Sweden between 1987 and 2002. The population comprised 2.8 million Swedish-born and 270,000 foreign-born individuals.

RESULTS

Incident hip fractures occurred in 239,842 Swedish-born and 12,563 foreign-born individuals. The hip fracture incidence rose with age for both groups and was higher for women than men amongst both Swedish-born and foreign-born individuals. The hip fracture incidence for the Swedish-born cohort was approximately twice that of immigrants. For example, at the age of 70 years, the annual hip fracture incidence (per 100,000) was 450 (95 % CI 446-454) for a Swedish-born woman and 239 (95 % CI 223-257) for a foreign-born woman at the time of immigration. The hip fracture incidence rose slowly with time from immigration (0.6 % per annum, 95 % CI 0.5-0.8 %) but remained significantly lower than for Swedish-born individuals even after 40 years of residence.

CONCLUSIONS

The incidence of hip fracture in Sweden is substantially lower in immigrants than in the population native to Sweden. Although there was a small rise in age- and sex-specific incidence after immigration, the incidence remained markedly lower than that observed in Swedish-born individuals. Thus, the use of a FRAX model for Sweden will overestimate the risk of fracture for foreign-born individuals living in Sweden.

Association between change in body weight after midlife and risk of hip fracture-the Singapore Chinese Health Study

The relationship between change in body weight and risk of fractures is inconsistent in epidemiologic studies. In this cohort of middle-aged to elderly Chinese in Singapore, compared to stable weight, weight loss ≥10 % over an average of 6 years is associated with nearly 40 % increase in risk of hip fracture.

INTRODUCTION

Findings on the relationship between change in body weight and risk of hip fracture are inconsistent. In this study, we examined this association among middle-aged and elderly Chinese in Singapore.

METHODS

We used prospective data from the Singapore Chinese Health Study, a population-based cohort of 63,257 Chinese men and women aged 45-74 years at recruitment in 1993-1998. Body weight and height were self-reported at recruitment and reassessed during follow-up interview in 1999-2004. Percent in weight change was computed based on the weight difference over an average of 6 years, and categorized as loss ≥10 %, loss 5 to <10 %, loss or gain <5 % (stable weight), gain 5 to <10 %, and gain ≥10 %. Multivariable Cox proportional hazards regression model was applied with adjustment for risk factors for hip fracture and body mass index (BMI) reported at follow-up interview.

RESULTS

About 12 % experienced weight loss ≥10 %, and another 12 % had weight gain ≥10 %. After a mean follow-up of 9.0 years, we identified 775 incident hip fractures among 42,149 eligible participants. Compared to stable weight, weight loss ≥10 % was associated with 39 % increased risk (hazard ratio 1.39; 95 % confidence interval 1.14, 1.69). Such elevated risk with weight loss ≥10 % was observed in both genders and age groups at follow-up (≤65 and >65 years) and in those with baseline BMI ≥20 kg/m(2).There was no significant association with weight gain.

CONCLUSIONS

Our findings provide evidence that substantial weight loss is an important risk factor for osteoporotic hip fractures among the middle-aged to elderly Chinese.

A systematic review on the use of daily subcutaneous administration of teriparatide for treatment of patients with osteoporosis at high risk for fracture in Asia

This systematic review aimed to examine the evidence for teriparatide in Asia for osteoporosis with a high fracture risk and for exploratory (unapproved) bone-related indications. MEDLINE (1946+), EMBASE (1966+), and ClinicalTrials.gov (2008+) were searched (16 August 2013); all studies of daily subcutaneous teriparatide 20 μg for bone-related conditions from China, Hong Kong, Japan, Republic of Korea, Philippines, Singapore, and Taiwan were included. Evidence on efficacy/safety was retrieved primarily from randomized controlled trials (10 publications) of postmenopausal women from Japan and China. In these studies, teriparatide was well tolerated; subjects had significantly greater increases in lumbar spine bone mineral density (BMD) from baseline compared with placebo, antiresorptive agents, or elcatonin/calcitonin; bone turnover markers increased from baseline and were sustained at elevated levels during teriparatide treatment. Few studies reported fracture risk, pain, or quality of life; one study showed a lower incidence of new-onset vertebral fracture with teriparatide versus antiresorptive agents. Nonrandomized studies (nine publications, one unpublished trial) conducted mainly in Taiwan, Japan, and the Republic of Korea provided supporting data for efficacy. The exploratory (unapproved) use of teriparatide (17 publications) for fracture healing and osteonecrosis of the jaw was described primarily in case reports. The clinical effectiveness of teriparatide for treatment of postmenopausal women with osteoporosis who are at high risk of fracture in Asia is focused primarily on improvements in BMD and tolerability. Recommended additional studies may include assessment of fracture risk and the effect of teriparatide on pain, quality of life, and mortality in Asia.

Screening and treatment of osteoporosis after hip fracture: comparison of sex and race

Most patients with osteoporosis (OP) are untreated and remain so even after hip fracture. Outcomes after osteoporotic hip fractures are worse among men and non-Caucasians compared with Caucasian women. We hypothesized that screening and treatment of OP after hip fracture remains low in men and non-Caucasian women. We identified all patients aged 65 yr or older with a primary diagnosis of hip fracture (ICD9-DM code 820.xx) discharged from an urban public hospital between January 1, 2000 and December 31, 2010. Patients with active malignancy (1 yr before or after the fracture) and Paget's disease were excluded. Also, patients were excluded if they had less than 2 encounters for post-event care at the hospital. Patient charts were reviewed to obtain information on demographics, post-fracture OP screening status (dual-energy X-ray absorptiometry [DXA] ordered or resulted), OP treatment status (prescription for oral bisphosphonates, raloxifene, zoledronic acid, calcitonin, or teriparatide), and referral to rheumatology clinic. Data were captured using Research Electronic Data Capture. Differences in frequency of patients who had been evaluated by DXA and/or prescribed antiosteoporotic therapy after hip fractures overall and stratified by sex and race were evaluated using Chi-squared tests. The study was approved by our hospital institutional review board. There were a total of 596 patients discharged with a primary diagnosis of hip fracture during the study period. After exclusions, 417 patients remained and were included in the analyses. The median age was 80yr (range: 65-95), 113 (27%) were men, and 243 were White women (57.9%). Overall, 10.3% of the patients were ordered DXA after their hospital discharge, 5.4% of men and 12.1% of women (p=0.05). A total of 19% received treatment for OP, and women were nearly 3 times more likely to receive treatment than men (23.2% vs 8%, p=0.004). The rates of DXA, treatment, and referral to rheumatology did not differ by race. The frequency of OP screening using DXA scan and the initiation of OP treatment was low in all patients after fragility fractures of hip. Women were more likely than men to receive DXA and significantly more likely to receive OP treatment. Although representative of only 1 hospital, these data suggest that more attention should be paid to possible OP among elderly patients hospitalized for hip fracture, and especially among men.

Racial/ethnic differences in hip and diaphyseal femur fractures

Contemporary femur fracture rates were examined in northern California women and compared by race/ethnicity. During 2006-2012, hip fracture rates declined, but diaphyseal fracture rates increased, especially in Asians. Women with diaphyseal fracture were younger and more likely to be bisphosphonate-treated. These disparities in femur fracture should be further examined.

INTRODUCTION

The epidemiology of diaphyseal femur fracture differs from proximal femur (hip) fracture, although few studies have examined demographic variations in the current era. This study examines contemporary differences in low-energy femur fracture by race/ethnicity in a large, diverse integrated health-care delivery system.

METHODS

The incidence of hip and diaphyseal fracture in northern California women aged ≥50 years old during 2006-2012 was examined. Hip (femoral neck and pertrochanteric) fractures were classified by hospital diagnosis codes, while diaphyseal (subtrochanteric and femoral shaft) fractures were further adjudicated based on radiologic findings. Demographic and clinical data were obtained from health plan databases. Fracture incidence was examined over time and by race/ethnicity.

RESULTS

There were 10,648 (97.3 %) hip and 300 (2.7 %) diaphyseal fractures among 10,493 women. The age-adjusted incidence of hip fracture fell from 281 to 240 per 100,000 women and was highest for white women. However, diaphyseal fracture rates increased over time, with a significant upward trend in Asians (9 to 27 per 100,000) who also had the highest rate of diaphyseal fracture. Women with diaphyseal fracture were younger than women with hip fracture, more likely to be of Asian race and to have received bisphosphonate drugs. Women with longer bisphosphonate treatment duration were also more likely to have a diaphyseal fracture, especially younger Asian women.

CONCLUSION

During 2006 to 2012, hip fracture rates declined, but diaphyseal fracture rates increased, particularly among Asian women. The association of diaphyseal fracture and bisphosphonate therapy should be further investigated with examination of fracture pattern.

Socioeconomic status in relation to incident fracture risk in the Study of Women's Health Across the Nation

We examined baseline and annual follow-up data (through annual follow-up visit 9) from a cohort of 2,234 women aged 42 to 52 years at baseline. Independent of financial status, higher educational level was associated with lower fracture incidence among non-Caucasian women but not among Caucasian women.

INTRODUCTION

This study was conducted to determine the associations of education and income with fracture incidence among midlife women over 9 years of follow-up.

METHODS

We examined baseline and annual follow-up data (through annual follow-up visit 9) from 2,234 participants of the Study of Women's Health Across the Nation, a cohort of women aged 42 to 52 years at baseline. We used Cox proportional hazards regression models to examine the associations of socioeconomic predictors (education, family-adjusted poverty-to-income ratio, and difficulty paying for basics) with time to first incident nontraumatic, nondigital, noncraniofacial fracture.

RESULTS

Independent of family-adjusted poverty-to-income ratio, higher educational level was associated with decreased time to first incident fracture among non-Caucasian women but not among Caucasian women (p(interaction) 0.02). Compared with non-Caucasian women who completed no more than high school education, non-Caucasian women who attained at least some postgraduate education had 87% lower rates of incident nontraumatic fracture (adjusted hazard ratio 0.13, 95% confidence interval [CI] 0.03-0.60). Among non-Caucasian women, each additional year of education was associated with a 16% lower odds of nontraumatic fracture (adjusted odds ratio 0.84, 95% CI 0.73-0.97). Income, family-adjusted poverty-to-income ratio, and degree of difficulty paying for basic needs were not associated with time to first fracture in Caucasian or non-Caucasian women.

CONCLUSIONS

Among non-Caucasian midlife women, higher education, but not higher income, was associated with lower fracture incidence. Elucidation of the mechanisms underlying the possible protective effects of higher educational level on nontraumatic fracture incidence may allow us to better target individuals at risk of future fracture.

Race/ethnic differences in associations between bone mineral density and fracture history in older men

SUMMARY

To determine whether there are race/ethnic differences in bone mineral density (BMD) by fracture history in men aged 65 years and older, we performed cross-sectional analysis in five large independent cohorts. Low BMD was associated with a higher prevalence of fracture in all cohorts, and the magnitude of the BMD differences by fracture status was similar across groups.

INTRODUCTION

We aimed to determine whether there are race/ethnic and geographic differences in bone mineral density by fracture history in men aged 65 years and older.

METHOD

The datasets included the Osteoporotic Fractures in Men (MrOS) Study (5,342 White, 243 African-American, 190 Asian, and 126 Hispanic), MrOS Hong Kong (1,968 Hong Kong Chinese), Tobago Bone Health Study (641 Afro-Caribbean), Namwon Study (1,834 Korean), and Dong-gu Study (2,057 Korean). The two Korean cohorts were combined.

RESULTS

The prevalence of self-reported non-traumatic fracture was US white, 17.1 %; Afro-Caribbean, 5.5 %; US African-American, 15.1 %; US Hispanic, 13.7 %; US Asian, 10.5 %; Hong Kong Chinese, 5.6 %, and Korean, 5.1 %. The mean differences in hip and lumbar spine BMD between subjects with fracture and without fracture were statistically significant in all cohorts except US African American and US Asian men. There was a significant race/ethnic interaction for lumbar spine BMD by fracture status (p for interaction = 0.02), which was driven by the small number of Hispanic men. There was no interaction for femoral neck or total hip BMD. There were no significant race/ethnic differences in the odds ratio of fracture by BMD.

CONCLUSIONS

Low BMD was associated with a higher prevalence of fracture in all cohorts and the magnitude of the BMD differences by fracture status was similar across groups suggesting homogeneity in the BMD-fracture relationship among older men.

How to decide intervention thresholds based on FRAX in central south Chinese postmenopausal women

The FRAX tool has been used to determine possible thresholds for therapeutic intervention; however, there are no FRAX-based intervention thresholds available for China, we proposed that the 10-year probability of major osteoporotic fracture and hip fracture of about 4.0 and 1.3%, respectively, may be acceptable intervention thresholds for central south Chinese postmenopausal women.

Comparative effectiveness of osteoporosis drugs in preventing secondary nonvertebral fractures in Taiwanese women

CONTEXT

The evidence for relative effectiveness of osteoporosis drugs in secondary prevention of nonvertebral fractures was unclear and could not be extrapolated to the Asian population.

OBJECTIVE

The objective of the study was to compare the relative effectiveness of different classes of osteoporosis drugs in secondary prevention of nonvertebral fractures in Taiwanese women.

DESIGN

This was a retrospective cohort study from 2003 to 2007, with up to 6 years of follow-up.

SETTING

The study included enrollees in Taiwan National Health Insurance.

PATIENTS

Patients older than 50 years, with vertebral/hip fracture and were new to osteoporosis therapy, were recruited.

INTERVENTION

Patients were classified into the alendronate, calcitonin, or raloxifene group, according to their exposure after follow-up.

MAIN OUTCOME MEASURE

The primary outcome of our study was the risk of incident nonvertebral fracture (hip, humerus, or radius fractures). A multivariate Cox proportional hazard model adjusted for fracture risk factors was used to compare the relative fracture risk among three treatment groups under on-treatment scenarios. Propensity score-matched hazard ratios were examined, and interactions between fracture incidence and patients' compliance were investigated as well.

RESULTS

There were 19 840, 9534, and 25 483 patients in the alendronate, raloxifene, and calcitonin groups, respectively. The fracture rates were highest in calcitonin recipients (4.57 per 100 person-years), followed by raloxifene and alendronate. Results from Cox analyses showed raloxifene (hazard ratio 1.47; 95% confidence interval 1.29-1.67) and calcitonin (hazard ratio 1.51; 95% confidence interval 1.29-1.75) had higher nonvertebral fracture risks as compared with alendronate. The risk differences were more pronounced in compliant patients.

CONCLUSION

We found alendronate users had the lowest secondary nonvertebral fracture risk, as compared with raloxifene and calcitonin users. Consistent results were found in a series of sensitivity analyses.

Estimation of 10-year probability bone fracture in a selected sample of Palestinian people using fracture risk assessment tool

BACKGROUND

The Fracture Risk Assessment (FRAX) tool has been developed by the World Health Organization (WHO) to calculate 10-year probability hip fracture (HP) or major osteoporotic fracture (MOF). The objective of this study was to assess the 10-year probability of MOF and HF among a selected sample of Palestinian people.

METHODS

A sample of 100 subjects was studied. Dual energy X-ray absorpitometry was performed to measure bone mineral density (BMD) which was then inserted into FRAX Palestine online WHO tool to calculate the 10-year probability of MOF and HF.

RESULTS

The median age of participants was 61.5 years and the majority (79%) were females. The median (interquartile range) of femoral hip BMD was 0.82 (0.76-0.92) g/cm². The mean vertebral and hip T scores were -1.41 ± 0.13 SDs and -0.91 ± 0.10 SDs respectively. About one fifth of the sample (21%) had vertebral osteoporosis and 5% had hip osteoporosis. The median (interquartile range) 10-year probability of MOF and HF based on BMD were 3.7 (2.43-6.18)%, and 0.30 (0.10-0.68)% respectively.

CONCLUSION

Osteoporosis is common among Palestinian people above 50 years old. Bone fracture prevention strategies and research should be a priority in Palestine. Using FRAX might be a helpful screening tool in primary healthcare centres in Palestine.

Validation of an osteoporosis self-assessment tool to identify primary osteoporosis and new osteoporotic vertebral fractures in postmenopausal Chinese women in Beijing

BACKGROUND

This study aimed to validate the effectiveness of the Osteoporosis Self-assessment Tool for Asians (OSTA) in identifying postmenopausal women at increased risk of primary osteoporosis and painful new osteoporotic vertebral fractures in a large selected Han Chinese population in Beijing.

METHODS

We assessed the performance of the OSTA in 1201 women. Subjects with an OSTA index > -1 were classified as the low risk group, and those with an index ≤ -1 were classified as the increased risk group. Osteoporosis is defined by a T-score ≤ 2.5 standard deviations according to the WHO criteria. All painful, new vertebral fractures were identified by X-ray and MRI scans with correlating clinical signs and symptoms. We determined the sensitivity, specificity, and area under the receiver operating characteristic (ROC) curve for correctly selecting women with osteoporosis and painful new vertebral fractures.

RESULTS

Of the study subjects, 29.3% had osteoporosis, and the prevalence of osteoporosis increased progressively with age. The areas under the ROC curves of the OSTA index (cutoff = -1) to identify osteoporosis in the femoral neck, total hip, and lumbar spine were 0.824, 0.824, and 0.776, respectively. The sensitivity and specificity of the OSTA index (cutoff = -1) to identify osteoporosis in healthy women were 66% and 76%, respectively. With regard to painful new vertebral fractures, the area under the ROC curve relating the OSTA index (cutoff = -1) to new vertebral fractures was 0.812.

CONCLUSIONS

The OSTA may be a simple and effective tool for identifying the risk of osteoporosis and new painful osteoporotic vertebral fractures in Han Chinese women.

Patient weighting of osteoporosis medication attributes across racial and ethnic groups: a study of osteoporosis medication preferences using conjoint analysis

We studied the ranking of osteoporosis (OP) medication attributes in a convenience sample of four different racial/ethnic groups in the United States. Our study showed that postmenopausal women differ in the ranking of OP medication attributes based on age, educational level, income, and prior fracture history.

INTRODUCTION

Decision making about OP medication-related behavior relies heavily on patient preferences about specific medication attributes. Patients may decide to initiate, change, or stop therapies based on ranking of perceived attributes of the therapy and their personal attitudes toward those attributes. We used MaxDiff, a form of conjoint analysis (Ryan and Farrar 2000), to explore patient weighting of attributes across four racial/ethnic groups at two sites in the United States and defined four critical attributes that influence such decisions (safety, efficacy, cost, and convenience) from qualitative interviews.

METHODS

We recruited a sample of 367 Postmenopausal (PM) women at risk of OP fractures from four racial/ethnic groups: Caucasian (n = 100), African American (n = 100), Asian American (n = 82), and Hispanic American (n = 85). Respondents completed a laptop-based questionnaire that included demographic items, several short scales on medical care preference and OP patient perceptions, and a MaxDiff procedure that determines comparative ranking of attributes either as least important or most important to their decisions.

RESULTS

MaxDiff analyses were done to evaluate the relative weight of specific statements for each participant and to determine whether racial/ethnic groups differed across dimensions. Overall, participants in all four groups rated efficacy > safety > cost > convenience.

CONCLUSIONS

Although there were no significant differences among the racial/ethnic groups on overall ranking of attributes, subgroup analyses revealed significant impact of age, education, income, and prior fracture on these decisions. The findings from this study suggest that postmenopausal women differ in their ranking of OP medication attributes, and healthcare providers must account for personal preferences in their communication about and selection of OP medications.

All-cause and cause-specific mortality after hip fracture among Chinese women and men: the Singapore Chinese Health Study

All-cause mortality risk persisted for 5 years after hip fractures in both men and women. There may be gender-specific differences in effect and duration of excess risk for cause-specific mortality after hip fracture.

INTRODUCTION

To determine all-cause and cause-specific mortality risk in the first 5 years after hip fracture in an Asian Chinese population.

METHODS

The Singapore Chinese Health Study is a population-based cohort of 63,257 middle-aged and elderly Chinese men and women in Singapore recruited between 1993 and 1998. This cohort was followed up for hip fracture and death via linkage with nationwide hospital discharge database and death registry. As of 31 December 2008, we identified 1,166 hip fracture cases and matched five non-fracture cohort subjects by age and gender for each fracture case. Cox proportional hazards and competing risks regression models with hip fracture as a time-dependent covariate were used to determine all-cause and cause-specific mortality risk, respectively.

RESULTS

Increase in all-cause mortality risk persisted till 5 years after hip fracture (adjusted hazard ratio, aHR = 1.58 [95 % CI, 1.35-1.86] for females and aHR = 1.64 [95 % CI, 1.30-2.06] for males). Men had higher mortality risk after hip fracture than women for deaths from stroke and cancer up to 1 year post-fracture but women with hip fracture had higher coronary artery mortality risk than men for 5 years post-fracture. Men had higher risk of death from pneumonia while women had increased risk of death from urinary tract infections. There was no difference in mortality risk by types of hip fracture surgery.

CONCLUSIONS

All-cause mortality risk persisted for 5 years after hip fractures in men and women. There are gender-specific differences in effect size and duration of excess mortality risk from hip fractures between specific causes of death.

Dietary B vitamin intake and risk of hip fracture: the Singapore Chinese Health Study

This prospective cohort study that comprehensively examined effects of different B vitamins in an Asian population showed an inverse relationship between dietary intake of pyridoxine and hip fracture risk in elderly women. These findings suggest that maintaining sufficient pyridoxine intake may be beneficial in preserving bone health in postmenopausal women.

INTRODUCTION

B vitamins have recently been investigated for their possible roles in maintaining bone health. Incidence of osteoporotic hip fracture has been rising in Asia, but epidemiological data on dietary B vitamins and risk of osteoporotic fractures are sparse. We aimed to examine the association between dietary intakes of B vitamins (thiamin, riboflavin, niacin, pyridoxine, folate, and cobalamin) and hip fracture risk among elderly Chinese in Singapore.

METHODS

The current study was conducted in the Singapore Chinese Health Study, which is a population-based cohort prospective study that enrolled a total of 63,257 men and women aged 45-74 years between 1993 and 1998. Dietary intakes of B vitamins were derived from a validated food frequency questionnaire and the Singapore Food Composition Database.

RESULTS

After a mean follow-up period of 13.8 years, 1,630 hip fracture incident cases were identified. A statistically significant inverse relationship between dietary pyridoxine intake and hip fracture risk was observed among women (p for trend = 0.002) but not among men. Compared to women in the lowest quartile intake (0.37-0.61 mg/1,000 kcal/day), women in the highest quartile intake (0.78-1.76 mg/1,000 kcal/day) had a 22 % reduction in hip fracture risk (hazard ratio 0.78, 95 % confidence interval 0.66-0.93). Dietary intakes of the other B vitamins of interest were not related to hip fracture risk.

CONCLUSIONS

Our findings suggest that maintaining adequate intake of pyridoxine may prevent osteoporotic fractures among elderly women.

Polymorphisms of muscle genes are associated with bone mass and incident osteoporotic fractures in Caucasians

The interaction between muscle and bone is complex. The aim of this study was to investigate if variations in the muscle genes myostatin (MSTN), its receptor (ACVR2B), myogenin (MYOG), and myoD1 (MYOD1) were associated with fracture risk, bone mineral density (BMD), bone mineral content (BMC), and lean body mass. We analyzed two independent cohorts: the Danish Osteoporosis Prevention Study (DOPS), comprising 2,016 perimenopausal women treated with hormone therapy or not and followed for 10 years, and the Odense Androgen Study (OAS), a cross-sectional, population-based study on 783 men aged 20-29 years. Nine tag SNPs in the four genes were investigated. In the DOPS, individuals homozygous for the variant allele of the MSTN SNP rs7570532 had an increased risk of any osteoporotic fracture, with an HR of 1.82 (95 % CI 1.15-2.90, p = 0.01), and of nonvertebral osteoporotic fracture, with an HR of 2.02 (95 % CI 1.20-3.41, p = 0.01). The same allele was associated with increased bone loss (BMC) at the total hip of 4.1 versus 0.5 % in individuals either heterozygous or homozygous for the common allele (p = 0.006), a reduced 10-year growth in bone area at the total hip of 0.4 versus 2.2 and 2.3 % in individuals heterozygous or homozygous for the common allele, respectively (p = 0.01), and a nonsignificantly increased 10-year loss of total-hip BMD of 4.4 versus 2.7 and 2.9 % in individuals heterozygous or homozygous for the common allele, respectively (p = 0.08). This study is the first to demonstrate an association between a variant in MSTN and fracture risk and bone loss. Further studies are needed to confirm the findings.

The contributions of First Nations ethnicity, income, and delays in surgery on mortality post-fracture: a population-based analysis

We examined the independent contributions of First Nations ethnicity and lower income to post-fracture mortality. A similar relative increase in mortality associated with fracture appears to translate into a larger absolute increase in post-fracture mortality for First Nations compared to non-First Nations peoples. Lower income also predicted increased mortality post-fracture.

INTRODUCTION

First Nations peoples have a greater risk of mortality than non-First Nations peoples. We examined the independent contributions of First Nations ethnicity and income to mortality post-fracture, and associations with time to surgery post-hip fracture.

METHODS

Non-traumatic fracture cases and fracture-free controls were identified from population-based administrative data repositories for Manitoba, Canada (aged≥50 years). Populations were retrospectively matched for sex, age (within 5 years), First Nations ethnicity, and number of comorbidities. Differences in mortality post-fracture of hip, wrist, or spine, 1996-2004 (population 1, n=63,081), and the hip, 1987-2002(Population 2, n=41,211) were examined using Cox proportional hazards regression to model time to death. For hip fracture, logistic regression analyses were used to model the probability of death within 30 days and 1 year.

RESULTS

Population 1: First Nations ethnicity was associated with an increased mortality risk of 30-53% for each fracture type. Lower income was associated with an increased mortality risk of 18-26%. Population 2: lower income predicted mortality overall (odds ratio (OR) 1.15, 95% confidence interval (CI) 1.07-1.23) and for hip fracture cases (OR 1.18, 95%CI 1.05-1.32), as did older age, male sex, diabetes, and >5 comorbidities (all p≤0.01). Higher mortality was associated with pertrochanteric fracture (OR 1.14, 95% CI 1.03-1.27), or surgery delay of 2-3 days (OR 1.34, 95% CI 1.18-1.52) or ≥4 days (OR 2.35, 95% CI 2.07-2.67).

CONCLUSION

A larger absolute increase in mortality post-fracture was observed for First Nations compared to non-First Nations peoples. Lower income and surgery delay>2 days predicted mortality post-fracture. These data have implications regarding prioritization of healthcare to ensure targeted, timely care for First Nations peoples and/or individuals with lower income.

The influence of the genetic and non-genetic factors on bone mineral density and osteoporotic fractures in Chinese women

To investigate the effects of genetic and non-genetic factors on bone mineral densities (BMDs) and osteoporotic fractures. This was a cross-sectional study to investigate the relationships between 18 SNPs and non-genetic factors with BMDs and osteoporotic fractures in 1012 Chinese Han women. Five SNPs in genes GPR177, CTNNB1, MEF2C, SOX6, and TNFRSF11B were associated with L1-4 or total hip BMDs. rs11898505 in SPTBN1 gene was associated with osteoporotic fractures. Subjects carrying the largest number of risk alleles (highest 10 %) not only had lower BMD values as compared to those carrying the least number of risk alleles (lowest 10 %), they also had a higher risk of fracture [P = 0.002, OR = 2.252, 95 %CI (1.136, 4.463)]. Results from multivariate stepwise regression analysis revealed that age [P < 0.001, OR = 1.038, 95 % CI (1.018, 1.058)], number of falls in a year [P < 0.001, OR = 2.347, 95 % CI (1.459, 3.774)], the G risk allele in rs11898505 [P = 0.023, OR = 1.559, 95 % CI (1.062, 2.290)], and the L1-4 BMD [P = 0.017, OR = 0.286, 95 % CI (0.102, 0.798)] were associated with the occurrence of osteoporotic fractures. Genetic (rs11898505) and non-genetic factors (age, number of falls in a year and L1-4 BMD) could work in concert to contribute to the risk of osteoporotic fractures.

Lifestyle and osteoporosis in middle-aged and elderly women: Chiba bone survey

Osteoporosis causes an enormous health and economic impact in Japan. We investigated the relation between lifestyle and bone fracture in middle-aged and elderly women. This was a population-based, multicenter, cross-sectional survey for postmenopausal osteoporosis in Chiba City, Japan (Chiba bone survey). This survey included 64,809 Japanese women aged > 40 years. All participants underwent anthropometric measurements including bone mineral density (BMD) and completed a structured, nurse-assisted, self-administered questionnaire also including patient lifestyle. Bone fracture during the recent 5 years was observed in 5.3%, and the fracture group had significantly higher age, BMI, and prevalence of delivery, family histories of kyphosis and hip fracture, diabetes mellitus (DM), dyslipidemia, kidney disease, exercise, fall, and osteoporosis, and had significantly lower BMD and proportion of menstruating participants. Logistic regression analysis revealed that bone fracture was closely associated with not only low bone mass but also age, fall, family histories of kyphosis and hip fracture, DM, kidney disease, menopause, and lifestyle factors of dieting, exercise, and alcohol. Women's health care focusing on lifestyle-related fracture risks such as dieting, exercise, and alcohol appears necessary to prevent bone fracture in postmenopausal osteoporosis.

Geographic differences in fractures among women

Osteoporotic fracture is associated with considerable morbidity and mortality in women throughout the world. However, significant variation in hip fracture rates among women from different nations has been observed and is likely to represent a combination of real and apparent differences due to ascertainment bias. Higher rates are observed in Caucasian women, with lowest rates observed in black women and intermediate rates among Asian women. These differences are likely to represent a combination of genetic and environmental differences; for example, among European women, the highest fracture rates are observed in Scandinavian women where vitamin D insufficiency is common. In all groups, an increase in absolute fracture numbers is anticipated due to demographic changes.

Ethnic differences in composite indices of femoral neck strength

Bone mineral density does not explain race/ethnicity differences in hip fracture risk. In this study, we demonstrated that race/ethnicity differences in composite hip strength indices were consistent with documented race/ethnicity differences in hip fracture risk, suggesting that unlike bone density, the composite indices may represent ethnicity-independent measures of bone strength.

INTRODUCTION

African-American and Asian women have lower risks of hip fracture than Caucasian women, but such racial/ethnic variation in hip fracture risk cannot be explained by bone mineral density (BMD). The composite indices of femoral neck strength integrate femoral neck and body size with BMD and predict hip fracture risk in Caucasian women. We hypothesize that unlike race/ethnic differences in BMD, race/ethnic differences in the composite strength indices would be consistent with race/ethnic differences in hip fracture risk.

METHODS

We studied a community-based sample of Caucasian (n = 968), African-American (n = 512), Chinese (n = 221), and Japanese (n = 239) women, premenopausal or in early perimenopause, from the Study of Women's Health Across the Nation.

RESULTS

Unadjusted indices were similar in Caucasian and African-American women but higher in Asian women. After adjusting for age, body mass index, and menopause status, all three minority groups had higher composite strength indices than Caucasian women. Foreign-born Japanese women had higher unadjusted and adjusted composite strength indices than US-born Japanese women, but such differences by nativity were not observed in Chinese women.

CONCLUSION

We concluded that composite strength indices have the potential to explain racial/ethnic differences in hip fracture risk, suggesting that composite strength indices may represent ethnicity-independent measures of bone strength. This contention needs to be verified by further research on the fracture predictive ability of composite strength indices in multi-ethnic longitudinal cohorts.

The post-fracture care gap among Canadian First Nations peoples: a retrospective cohort study

Despite targeted attempts to reduce post-fracture care gaps, we hypothesized that a larger care gap would be experienced by First Nations compared to non-First Nations people. First Nations peoples were eight times less likely to receive post-fracture care compared to non-First Nations peoples, representing a clinically significant ethnic difference in post-fracture care.

INTRODUCTION

First Nations peoples are the largest group of aboriginal (indigenous or native) peoples in Canada. Canadian First Nations peoples have a greater risk of fracture compared to non-First Nations peoples. We hypothesized that ethnicity might be associated with a larger gap in post-fracture care.

METHODS

Non-traumatic major osteoporotic fractures for First Nations and non-First Nations peoples aged ≥ 50 years were identified from a population-based data repository for Manitoba, Canada between April 1996 and March 2002. Logistic regression analysis was used to examine the probability of receiving a BMD test, a diagnosis of osteoporosis, or beginning an osteoporosis-related drug in the 6 months post-fracture.

RESULTS

A total of 11,234 major osteoporotic fractures were identified; 502 occurred in First Nations peoples. After adjustment for confounding covariates, First Nations peoples were less likely to receive a BMD test [odds ratio (OR) 0.1, 95% confidence interval (CI), 0.0-0.5], osteoporosis-related drug treatment (OR, 0.5; 95% CI, 0.3-0.7), or a diagnosis of osteoporosis (OR, 0.5; 95% CI, 0.3-0.7) following a fracture compared to non-First Nations peoples. Females were more likely to have a BMD test (OR, 5.0; 95% CI, 2.6-9.3), to be diagnosed with osteoporosis (OR, 1.7; 95% CI, 1.5-2.0), and to begin drug treatment (OR, 4.1; 95% CI, 2.7-6.4) compared to males.

CONCLUSIONS

An ethnicity difference in post-fracture care was observed. Further work is needed to elucidate underlying mechanisms for this difference and to determine whether failure to initiate treatment originates with the medical practitioner, the patient, or a combination of both. It is imperative that all residents of Manitoba receive efficacious and equal care post-fracture, regardless of ethnicity.

Ethnic difference of clinical vertebral fracture risk

Vertebral fractures are the most common osteoporotic fractures. Data on the vertebral fracture risk in Asia remain sparse. This study observed that Hong Kong Chinese and Japanese populations have a less dramatic increase in hip fracture rates associated with age than Caucasians, but the vertebral fracture rates were higher, resulting in a high vertebral-to-hip fracture ratio. As a result, estimation of the absolute fracture risk for Asians may need to be readjusted for the higher clinical vertebral fracture rate.

INTRODUCTION

Vertebral fractures are the most common osteoporotic fractures. Data on the vertebral fracture risk in Asia remain sparse. The aim of this study was to report the incidence of clinical vertebral fractures among the Chinese and to compare the vertebral-to-hip fracture risk to other ethnic groups.

METHODS

Four thousand, three hundred eighty-six community-dwelling Southern Chinese subjects (2,302 women and 1,810 men) aged 50 or above were recruited in the Hong Kong Osteoporosis Study since 1995. Baseline demographic characteristics and medical history were obtained. Subjects were followed annually for fracture outcomes with a structured questionnaire and verified by the computerized patient information system of the Hospital Authority of the Hong Kong Government. Only non-traumatic incident hip fractures and clinical vertebral fractures that received medical attention were included in the analysis. The incidence rates of clinical vertebral fractures and hip fractures were determined and compared to the published data of Swedish Caucasian and Japanese populations.

RESULTS

The mean age at baseline was 62 ± 8.2 years for women and 68 ± 10.3 years for men. The average duration of follow-up was 4.0 ± 2.8 (range, 1 to 14) years for a total of 14,733 person-years for the whole cohort. The incidence rate for vertebral fracture was 194/100,000 person-years in men and 508/100,000 person-years in women, respectively. For subjects above the age of 65, the clinical vertebral fracture and hip fracture rates were 299/100,000 and 332/100,000 person-years, respectively, in men, and 594/100,000 and 379/100,000 person-years, respectively, in women. Hong Kong Chinese and Japanese populations have a less dramatic increase in hip fracture rates associated with age than Caucasians. At the age of 65 or above, the hip fracture rates for Asian (Hong Kong Chinese and Japanese) men and women were less than half of that in Caucasians, but the vertebral fracture rate was higher in Asians, resulting in a high vertebral-to-hip fracture ratio.

CONCLUSIONS

The incidences of vertebral and hip fractures, as well as the vertebral-to-hip fracture ratios vary in Asians and Caucasians. Estimation of the absolute fracture risk for Asians may need to be readjusted for the higher clinical vertebral fracture rate.

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.

Bone mineral density enhances use of clinical risk factors in predicting ten-year risk of osteoporotic fractures in Chinese men: the Hong Kong Osteoporosis Study

This prospective study aimed to determine the risk factors and the 10-year probability of osteoporotic fracture in Southern Chinese men. The findings show substantial population differences in fracture incidence and risk prediction compared to the FRAX(TM) model, and the addition of BMD information to clinical risk factor assessment improved fracture risk prediction in Chinese men.

INTRODUCTION

Clinical risk factors with or without bone mineral density (BMD) measurements are increasingly recognized as reliable predictors of fracture risk. Prospective data on fracture incidence in Asian men remain sparse. This prospective study aimed to determine the risk factors and the 10-year absolute fracture risk in Southern Chinese men.

METHODS

This is a part of the Hong Kong Osteoporosis Study. One thousand eight hundred ten (1,810) community-dwelling, treatment-naive men aged 50 years or above were evaluated. Baseline demographic characteristics, clinical risk factors and BMD were recorded. Ten-year risk of osteoporotic fracture was calculated using Cox proportional hazards models.

RESULTS

The mean age of subjects was 68.0 ± 10.3 years. After a mean follow-up period of 3.5±2.9 years (range 1 to 14 years), 37 incident low-trauma fractures were recorded. The incidence for all osteoporotic fractures and hip fractures was 635/100,000 and 123/100,000 person-years, respectively. The most significant predictors of osteoporotic fracture were history of fall (RR 14.5), femoral neck BMD T-score < -2.5 (RR 13.8) and history of fracture (RR 4.4). Each SD reduction in BMD was associated with a 1.8 to 2.6-fold increase in fracture risk. Subjects with seven clinical risk factors and BMD T-score of -1 had an absolute 10-year risk of osteoporotic fracture of 8.9%, but this increased to 22.7% if they also had a femoral neck BMD T-score of -2.5.

CONCLUSIONS

These findings show substantial population differences in fracture incidence and risk prediction. The addition of BMD information to clinical risk factor assessment improved fracture risk prediction in Chinese men.

Official Positions for FRAX® clinical regarding international differences from Joint Official Positions Development Conference of the International Society for Clinical Densitometry and International Osteoporosis Foundation on FRAX®

Osteoporosis is a serious worldwide epidemic. Increased risk of fractures is the hallmark of the disease and is associated with increased morbidity, mortality and economic burden. FRAX® is a web-based tool developed by the Sheffield WHO Collaborating Center team, that integrates clinical risk factors, femoral neck BMD, country specific mortality and fracture data and calculates the 10 year fracture probability in order to help health care professionals identify patients who need treatment. However, only 31 countries have a FRAX® calculator at the time paper was accepted for publication. In the absence of a FRAX® model for a particular country, it has been suggested to use a surrogate country for which the epidemiology of osteoporosis most closely approximates the index country. More specific recommendations for clinicians in these countries are not available. In North America, concerns have also been raised regarding the assumptions used to construct the US ethnic specific FRAX® calculators with respect to the correction factors applied to derive fracture probabilities in Blacks, Asians and Hispanics in comparison to Whites. In addition, questions were raised about calculating fracture risk in other ethnic groups e.g., Native Americans and First Canadians. In order to provide additional guidance to clinicians, a FRAX® International Task Force was formed to address specific questions raised by physicians in countries without FRAX® calculators and seeking to integrate FRAX® into their clinical practice. The main questions that the task force tried to answer were the following: The Task Force members conducted appropriate literature reviews and developed preliminary statements that were discussed and graded by a panel of experts at the ISCD-IOF joint conference. The statements approved by the panel of experts are discussed in the current paper.

FRAX® International Task Force of the 2010 Joint International Society for Clinical Densitometry & International Osteoporosis Foundation Position Development Conference

Osteoporosis is a serious worldwide epidemic. FRAX® is a web-based tool developed by the Sheffield WHO Collaborating Center team, that integrates clinical risk factors and femoral neck BMD and calculates the 10 year fracture probability in order to help health care professionals identify patients who need treatment. However, only 31 countries have a FRAX® calculator. In the absence of a FRAX® model for a particular country, it has been suggested to use a surrogate country for which the epidemiology of osteoporosis most closely approximates the index country. More specific recommendations for clinicians in these countries are not available. In North America, concerns have also been raised regarding the assumptions used to construct the US ethnic specific FRAX® calculators with respect to the correction factors applied to derive fracture probabilities in Blacks, Asians and Hispanics in comparison to Whites. In addition, questions were raised about calculating fracture risk in other ethnic groups e.g., Native Americans and First Canadians. The International Society for Clinical Densitometry (ISCD) in conjunction with the International Osteoporosis Foundation (IOF) assembled an international panel of experts that ultimately developed joint Official Positions of the ISCD and IOF advising clinicians regarding FRAX® usage. As part of the process, the charge of the FRAX® International Task Force was to review and synthesize data regarding geographic and race/ethnic variability in hip fractures, non-hip osteoporotic fractures, and make recommendations about the use of FRAX® in ethnic groups and countries without a FRAX® calculator. This synthesis was presented to the expert panel and constitutes the data on which the subsequent Official Positions are predicated. A summary of the International Task Force composition and charge is presented here.

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

SUMMARY

Participants in the observational study of the Women's Health Initiative (WHI) were studied to determine if ethnic differences in femur geometry can help to explain differences in hip fracture rates. Structural differences in femurs of African and Mexican-American women appear to be consistent with lower rates of hip fractures vs. whites.

INTRODUCTION

Ethnic origin has a major influence on hip fractures, but the underlying etiology is unknown. We evaluated ethnic differences in hip fracture rates among 159,579 postmenopausal participants in the WHI then compared femur bone mineral density (BMD) and geometry among a subset with dual X-ray absorptiometry (DXA) scans of the hip and total body.

METHODS

The subset included 8,206 non-Hispanic whites, 1,476 African-American (AA), 704 Mexican-American (MA), and 130 Native Americans (NA). Femur geometry derived from hip DXA using hip-structure analysis (HSA) in whites was compared to minority groups after adjustment for age, height, weight, percent lean mass, neck-shaft angle and neck length, hormone use, chronic disease (e.g., diabetes, rheumatoid arthritis, cancer), bone active medications (e.g., corticosteroids, osteoporosis therapies), and clinical center.

RESULTS

Both AA and MA women suffered hip fractures at half the rate of whites while NA appeared to be similar to whites. The structural advantage among AA appears to be due to a slightly narrower femur that requires more bone tissue to achieve similar or lower section moduli (SM) vs. whites. This also underlies their higher BMD (reduces region area) and lower buckling ratios (buckling susceptibility). Both MA and NA women had similar advantages vs. whites at the intertrochanter region where cross-sectional area and SM were higher but with no differences at the neck. NA and MA had smaller bending moments vs. whites acting in a fall on the hip (not significant in small NA sample). Buckling ratios of MA did not differ from whites at any region although NA had 4% lower values at the IT region.

CONCLUSION

Differences in the geometry at the proximal femur are consistent with the lower hip fracture rates among AA and MA women compared to whites.

Importance of bone mineral density measurements in evaluating fragility bone fracture risk in Asian Indian men

We evaluated the effect of BMD on fracture risk prediction using FRAX® among Asian Indian men when used in conjunction with clinical risk factors. A majority of our subjects were either osteopenic or osteoporotic, and their fracture risk increased when FRAX® was used in conjunction with femur neck T-scores.

INTRODUCTION

Asian Indian men living in the United States may represent a population that is at high and underappreciated risk for fragility bone fractures.

PURPOSE

To evaluate the effect of BMD on fracture risk prediction using FRAX® among Asian Indian men when used in conjunction with clinical risk factors.

METHODS

Forty four Asian Indian men (mean age 64.9 (±8.4) years) who had lived in the United States for an average of 33.6 (±10.6) years underwent BMD measurement at the proximal femur. Subjects were subjected to a general physical exam and history of fracture, hip fracture in a parent, current smoking and alcohol use, and diagnosis of inflammatory arthritis was obtained. Data from each subject were entered into the FRAX® algorithm and 10-year fracture probabilities were calculated using clinical risk factors (CRFs) alone and in combination with femur neck T-scores.

RESULTS

Thirteen subjects (29.5%) had femur neck T-scores ≥ -1.0, 28 (63.6%) T-scores between -1.0 and -2.5, and three (6.8%) T-scores < -2.5. The 10-year probability of a major osteoporotic fracture based on a combination of clinical risk factors and femur neck T-scores was significantly higher than the fracture probability based on clinical risk factors alone (t(43) = 2.58, p = 0.01).

CONCLUSIONS

Among Asian Indian men, the 10-year probability of a major osteoporotic fracture increases when femur neck T-scores are added to clinical risk factors in the FRAX® algorithm, and this population have a high fracture probability even in the absence of clinical risk factors.

Ten-year fracture probability in Hong Kong Southern Chinese according to age and BMD femoral neck T-scores

This study estimated the 10-year probability of osteoporotic fracture in Hong Kong Southern Chinese based on a simplified model of the recently developed WHO fracture risk prediction tool (FRAX). Thus, the data provides further insights into potential development of a population-specific FRAX model for Hong Kong in the future.

INTRODUCTION

The purpose of this paper was to estimate the 10-year probability of osteoporotic fracture in Hong Kong (HK) Southern Chinese according to age and bone mineral density (BMD) T-score at the femoral neck based on the methodology of the FRAX risk assessment tool calibrated to the epidemiology of HK.

METHODS

Hip fracture data was obtained from the Clinical Data Analysis Reporting System (CDAS) of the Hospital Authority of HK and population size and death rates were taken from the HK Government Census and Statistics Department. Fracture probability was calculated using the cut-off values for T-scores derived from the NHANES III data for Caucasian women aged 20-29 years for BMD at the femoral neck.

RESULTS

In this study, the 10-year probability of osteoporotic fracture in HK Southern Chinese increased markedly with increasing age and decreasing femoral neck BMD T-scores in both women and men. Interestingly, at low T-scores, the increase in 10-year probability of osteoporotic fracture in women with age was greater than in men. Fracture probabilities were substantially higher than those from mainland China.

CONCLUSIONS

Based on this evidence, and until we have HK Southern Chinese population-specific information, we recommend the application of the Caucasian risk profile to calculate the absolute fracture risk for HK Southern Chinese subjects.

Cross-geographic region differences in quality of life in women with and without vertebral fracture

SUMMARY

Not much is known about cross-geographic region differences in quality of life (QoL) in women with and without prevalent vertebral fractures (VFX). QoL differed between continents, countries, and ethnicities. The observed differences in QoL mostly appeared larger than the difference in QoL between women with or without mild to moderate VFX.

INTRODUCTION

Quality of life (QoL) is an increasingly important outcome measure in randomized controlled trials and cost-utility studies. However, not much is known about cross-geographic region differences in QoL. The objective of this study was to describe the cross-geographic region differences in QoL in women with and without mild to moderate prevalent vertebral fractures (VFX).

METHODS

The study was performed using baseline data of the bazedoxifene study. The study was carried out in 25 countries in six continents (n = 7117). QoL was assessed using the index and Visual Analogue Scale (VAS) scores of the EQ-5D, Qualeffo-41, and Women's Health Questionnaire (WHQ). VFX were assessed using semi-quantitative and quantitative morphometric methods.

RESULTS

In general, all four instruments followed more or less the same pattern. In most analyses, the reported QoL was lowest in Asia and Europe and highest in North America and Oceania. To examine the influence of ethnicity, North and South America were stratified on race. In both continents, a lower QoL was observed in Hispanic people.

CONCLUSIONS

QoL differed between continents, countries, and ethnicities. The observed differences in QoL appeared larger between most continents and countries than the difference in QoL between women with or without mild to moderate VFX.

Ultrasound measurements of the calcaneus: effects of ethnicity

This study investigated whether there were differences in quantitative ultrasound (QUS) of the calcaneus between African-American and Caucasian females. QUS-1X, an ultrasonometer by Metra Biosystems Inc., was used to determine broadband ultrasound attenuation (UBI-4) using Burg Spectral Estimation in decibels/megahertz. The average transit time through the heel (TTH) in microseconds was used to estimate bone size. A multiple factor index taking into account bone size, UBI-4T, was calculated by dividing UBI-4 by TTH in decibels/(Megahertz x microseconds). Results showed that premenopausal Caucasian females (n = 37) have approx 6-8% lower values (p < 0.05) of QUS indices than their African-American (n = 54) counterparts. However, after adjusting for bone size, the differences in attenuation disappeared. Pilot data for males (Caucasian: n = 16, African-American: n = 18) suggest that the differences in QUS appear to be related to bone size. The limited scope of our study supports the fact that there are differences in QUS between premenopausal Caucasian and African-American females, but not with the same magnitude as evidenced by dual X-ray absorptiometry. We recommend that more data be collected on ethnic differences across all age ranges, to help understand how QUS may be used to assess bone mass and determine its value either as a screening tool to diagnose low bone mass or as a tool to predict osteoporotic fracture within various ethnic groups.