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.

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.

An efficient case finding strategy to diagnose osteoporosis in a developing society with low treatment frequency

OBJECTIVES

Osteoporosis is a debilitating condition with rising frequency of fragility fractures with advancing age. Life expectancy increases in developing societies with the emergence of osteoporosis. There is a need for a simple protocol to diagnose fractures that merit treatment for osteoporosis.

METHODS

Evaluation of all consecutive lateral chest radiographs performed at the National Hospital in the capital city in Greenland over a 3-month period for vertebral body heights at the anterior, middle and posterior regions. Use of anti-osteoporotic drug was evaluated from records of dispensed drugs from Greenland National Pharmacy.

RESULTS

1869 vertebrae were evaluated on radiographs from 203 subjects. On average 9.2 vertebrae (range 5-13) qualified for evaluation in each individual. Median (range) age was 55 (30-82) years. Any vertebral deformity above 25 (20) % was seen in 28.6 (50.2) %. More than one fracture was seen in 10.3 (27.1) %. Fractures occurred in 18.5 (36.9) % of patients from the General Medicine Clinic and in 33.3 (56.5) % of inpatients (p = 0.029). The occurrence of vertebral fractures increased with age (p < 0.001) and hosting more than one vertebral fracture was markedly more frequent after the age of 60 years [OR, 95 % CI 9.6, 3.1-30 (5.7, 2.9-11); p < 0.001] after correction for gender in logistic regressions. The National Pharmacy handed out anti-osteoporotic drugs equal to the treatment of 36 individuals.

CONCLUSIONS

Vertebral fractures that merit treatment can be readily diagnosed from lateral chest radiographs taken in routine clinical work-up. They are common in Greenland as demonstrated by this simple protocol to improve diagnosis and treatment of osteoporosis in a developing society.

Predictors of mortality, hospital utilization, and the role of race in outcomes in head and neck trauma

OBJECTIVE

A retrospective cross-sectional analysis was undertaken to determine the impact of race and insurance status on trauma outcomes in patients admitted to a Level I trauma center following head and neck fractures.

STUDY DESIGN

Putative predictive factors, including injury mechanism, hemorrhagic shock, injury severity score (ISS), race, gender, and insurance status, were used in a multivariate outcome analysis to determine their influence on length of hospital stay, number of procedures performed, discharge status, and mortality; P < .05 was significant.

RESULTS

Proportionately more male patients (76.5%) sustained head and neck fractures compared with females (23.5%). Blacks and Hispanics sustained proportionately more gunshot wounds (GSWs) compared with Whites, 16:1 and 7:1, respectively. There were no significant differences in length of hospital stay and mortality based on race or insurance status. Mortality was related to age, GSW as a mechanism of injury, increasing ISS, and shock on admission.

CONCLUSIONS

Minority race and insurance status did not correlate with worse outcomes. Treatment biases in the acutely injured patient with head and neck injuries may be less prevalent than thought, if we consider mortality and utilization of care as primary outcome measures.

The association between aortic calcification and fracture risk in postmenopausal women in China: the prospective Chongqing osteoporosis study

Purpose

Fractures are associated with cardiovascular diseases in the elderly. The purpose of the present study was to investigate the association between aortic calcification (AC) and the risk of vertebral fractures in postmenopausal Chinese women.

Methods

A prospective study with 5 years of follow-up in 1724 postmenopausal women (aged 50 years old and older) was conducted from July 2005 to June 2010. Dual energy X-ray absorptiometry was utilized to evaluate bone mineral density (BMD). Aortic calcification score (ACS) was determined by a semi-quantitative method and was further categorized into four groups. Cox proportional hazards models were established to assess the association between AC and the risk of vertebral fractures.

Results

For subjects with AC, the incidence of vertebral fractures was higher than that of those without AC (p<0.01). After adjustment for age and other potential confounders, it was found that severe AC (G4, ACS>6; G3, ACS = 3–6) was associated with vertebral fractures. Severe AC (G4) was associated with non-vertebral fractures. There were higher risk for the vertebral fractures in two groups and higher risk for non-vertebral fractures in one group.

Conclusions

The results of the current study indicate that severe AC is associated with a significantly increased risk of vertebral fractures and non-vertebral fractures in postmenopausal women in China.

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.

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.

Aortic calcification and bone metabolism: the relationship between aortic calcification, BMD, vertebral fracture, 25-hydroxyvitamin D, and osteocalcin

The aim of this study was to investigate the relationship between aortic calcification (AC) and low bone mineral density (BMD), 25(OH)D, C-terminal telopeptide (CTx), and osteocalcin levels in Asian women. We also tried to find the association between AC and the risk of vertebral fracture. We included 769 patients in this study. All patients underwent QCT. Aortic calcium score (ACS) was quantified by the Agatston scoring method. Spinal fracture was defined by lumbar spine radiography. Among 769 subjects, 96 had at least one vertebral fracture and 345 had AC. ACS positively correlated with age. Osteocalcin, CTx, 25(OH)D, total-hip trabecular BMD (tBMD), femoral neck tBMD, and vertebral tBMD were inversely related with ACS. However, cortical BMD (cBMD) did not correlate with ACS. Among these parameters, only osteocalcin significantly correlated with ACS, even after adjusting for age. We divided the subjects into two groups based on the presence of AC to determine the association between AC and vertebral fracture. Multivariate logistic regression analysis showed that age, tBMD of each site, and AC were associated with vertebral fractures. After adjusting for confounding factors, patients with AC had more than a threefold increased risk of vertebral fracture (OR = 3.29-3.57, P < 0.05 according to site). This study suggests that high ACS is related to low tBMD but not cBMD. Furthermore, our findings indicate that this relationship is definitely age-dependent. Finally, we found that AC is significantly associated with the prevalence of vertebral fracture in Asian women.

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 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.

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.

Prevalent vertebral fractures in black women and white women

Vertebral fractures are the most common osteoporotic fracture. Hip and clinical fractures are less common in black women, but there is little information on vertebral fractures. We studied 7860 white and 472 black women >or=65 yr of age enrolled in the Study of Osteoporotic Fractures. Prevalent vertebral fractures were identified from lateral spine radiographs using vertebral morphometry and defined if any vertebral height ratio was >3 SD below race-specific means for each vertebral level. Information on risk factors was obtained by questionnaire or examination. Lumbar spine, total hip, and femoral neck BMD and BMC were measured by DXA. The prevalence of vertebral fractures was 10.6% in black and 19.1% in white women. In age-adjusted logistic regression models, a 1 SD decrease in femoral neck BMD was associated with 47% increased odds of fracture in black women (OR = 1.47; 95% CI, 1.12-1.94) and 80% increased odds in white women (OR = 1.80; 95% CI, 1.68-1.94; interaction p = 0.14). The overall lower odds of fracture among black women compared with white women was independent of femoral neck BMD and other risk factors (OR = 0.51; 95% CI, 0.37-0.72). However, the prevalence of vertebral fractures increased with increasing number of risk factors in both groups. The prevalence of vertebral fractures is lower in black compared with white women but increases with age, low BMD, and number of risk factors.

Risk factors for prevalent vertebral fractures in black and white female densitometry patients

This cross-sectional study compared risk factors for prevalent vertebral fractures (diagnosed using densitometric spine image Vertebral Fracture Assessment [VFA]) in 176 black and 345 white women recruited during their clinical bone mineral density (BMD) testing at the University of Chicago Hospitals. We used logistic regression to assess the association of prevalent vertebral fractures and risk factors (age, height loss, history of nonvertebral fractures, BMD, and use of corticosteroids). The prevalence of vertebral fractures was 21% for both races. All risk factors of interest were significantly associated with vertebral fractures in white women. Among black women, only age and corticosteroid use were found to be significant predictors of presence of vertebral fracture(s). In women without history of corticosteroid use, the probability of having vertebral fracture(s) given age was lower (p=0.02) in black subjects. In 77 patients with a history of corticosteroid use, the probability of having vertebral fracture(s) was higher in black than in white women after adjustment for age (p=0.045), BMD (p=0.045), or cumulative corticosteroid dose (p=0.08). Fewer black women were prescribed pharmacologic therapy for osteoporosis, regardless of their BMD level and corticosteroid use. We conclude that use of corticosteroids may be associated with relatively greater vertebral fracture risk in blacks than in whites.

Racial differences in the prevalence of vertebral fractures in older men: the Baltimore Men's Osteoporosis Study

Older black men have higher adjusted bone mineral density (BMD) and a lower adjusted rate of decline in hip BMD than older white men. There are few published data on the prevalence of morphometric vertebral fractures in older white men and no published data for older black men. The study's objective was to estimate the prevalence of vertebral fractures in older men and explore differences in prevalence between older white and black men. Subjects included five hundred forty-two men (415 white and 127 black) aged 65 and above (mean age of 74.0+/-5.7 years) participating in the longitudinal component of the Baltimore Men's Osteoporosis Study. Radiographs of the thoracic and lumbar spine were obtained using standard protocols and read for the presence of vertebral deformities using binary semiquantitative techniques. Quantitative morphometry was performed and vertebral fractures were defined using the Melton-Eastell method. BMD was measured at the femoral neck, total hip and lumbar spine. Participants also completed self- and interviewer-administered questionnaires and underwent standardized clinical examinations. One or more vertebral fractures were present in 30 of 514 men with available radiographs: estimated prevalence 5.8% (95% confidence intervals [CI]: 4.0, 8.3%). Prevalence was significantly higher in white than black men, 7.3% vs 0.9% (Fishers' exact p =0.01): age-adjusted odds ratio=8.3 (95% CI: 1.1, 62.5). Among white men, there was no significant difference in age-adjusted femoral neck or total hip BMD or frequency or severity of back pain between men with and without vertebral fractures. In conclusion, older white men have a higher prevalence of vertebral fractures than older black men. This may be related to differences in BMD between these groups.

Osteoporosis and fracture risk in women of different ethnic groups

Osteoporosis and 1-year fracture risk were studied in 197,848 postmenopausal American women from five ethnic groups. Weight explained differences in BMD, except among blacks, who had the highest BMD. One SD decrease in BMD predicted a 50% increased fracture risk in each group. Despite similar relative risks, absolute fracture rates differed.

INTRODUCTION

Most information about osteoporosis comes from studies of white women. This study describes the frequency of osteoporosis and the association between BMD and fracture in women from five ethnic groups.

MATERIALS AND METHODS

This study was made up of a cohort of 197,848 community-dwelling postmenopausal women (7784 blacks, 1912 Asians, 6973 Hispanics, and 1708 Native Americans) from the United States, without known osteoporosis or a recent BMD test. Heel, forearm, or finger BMD was measured, and risk factor information was obtained; 82% were followed for 1 year for new fractures. BMD and fracture rates were compared, adjusting for differences in covariates.

RESULTS

By age 80, more than one-fifth of women in each ethnic group had peripheral BMD T scores <-2.5. Black women had the highest BMD; Asian women had the lowest. Only the BMD differences for blacks were not explained by differences in weight. After 1 year, 2414 new fractures of the spine, hip, forearm, wrist, or rib were reported. BMD at each site predicted fractures equally well within each ethnic group. After adjusting for BMD, weight, and other covariates, white and Hispanic women had the highest risk for fracture (relative risk [RR] 1.0 [referent group] and 0.95, 95% CI, 0.76, 1.20, respectively), followed by Native Americans (RR, 0.87; 95% CI, 0.57, 1.32), blacks (RR, 0.52; 95% CI, 0.38, 0.70), and Asian Americans (RR, 0.32; 95% CI, 0.15, 0.66). In age- and weight-adjusted models, each SD decrease in peripheral BMD predicted a 1.54 times increased risk of fracture in each ethnic group (95% CI, 1.48-1.61). Excluding wrist fractures, the most common fracture, did not materially change associations.

CONCLUSIONS

Ethnic differences in BMD are strongly influenced by body weight; fracture risk is strongly influenced by BMD in each group. Ethnic differences in absolute fracture risk remain, which may warrant ethnic-specific clinical recommendations.

Evaluation of vertebral fractures on lateral chest radiographs of inner-city postmenopausal women

We assessed the prevalence of vertebral fractures as a marker for osteoporosis on lateral chest radiographs in inner-city, minority, postmenopausal women. We reviewed outpatient lateral chest radiographs on all women 55 years and older at an inner-city hospital during two randomly selected months, August 2000 and April 2002. There were 106 women with a mean age of 65 (range 55-89) years, 45 were Hispanic, 42 Black, 9 White, 10 of other ethnicity. Deformity was graded on a 0-3 scale with Grades 2 (moderate) and 3 (severe) deformities considered fractures. Interval lateral chest radiographs within 1-2 years were evaluated. Of the group 25% (26/106) had vertebral fractures. The fracture prevalence increased with age: 13% (17/54) of women under 65 years and 37% (19/52) of women 65 years and older had fractures ( P < 0.05). The fracture was described as part of the radiographic report in only 15% (4/26) of the women. Of the group 15% (16/106) had interval lateral chest radiographs. Among those with interval lateral chest radiographs, 19% (3/16) developed new fractures. In this series 29% (31/106) of women were scheduled for bone density studies, but the studies were only completed in 6% (6/106). Lateral chest radiographs showed that vertebral fractures occurred commonly, increased with age, and progressed on follow-up. In a population of underserved minority women, the lateral chest radiograph provides an opportunity to identify women with osteoporosis for possible treatment.

Bone fragility in Asian and Caucasian men

Hip and vertebral fractures are a public health problem in men of Asian and Caucasian origin. Inferences regarding gender and racial/ethnic differences in fracture rates must be made cautiously as problems in case ascertainment and classification of hip fractures, and problems in defining what constitutes a vertebral 'fracture' have not been solved. However, methodological issues probably do not entirely account for the heterogeneity of fracture patterns. There is likely to be a wide variation in fracture rates from country to country in Asia as reported in studies in Europe. The reasons for this heterogeneity are unknown. Caucasian men lose similar amounts of bone as Caucasian women during ageing from the endosteal surface of the bone. Net bone loss is less in men than women because men form more periosteal bone during ageing than do women. The extent of periosteal and endosteal bone modelling and remodelling have not been studied in Asian men and women. Nor have there been hypothesis-driven studies designed to compare periosteal apposition and endosteal bone loss in Asian males compared to Caucasian males. Sex hormone deficiencies contribute to abnormalities in skeletal size and mass during growth, remodelling imbalance and bone loss during ageing in men. The larger peak bone size and greater periosteal apposition with ageing in men compared to women is most likely to be androgen-dependent in Caucasians and Asians. Androgen deficiency may also partly account for reduced bone formation and negative bone balance at the basic multicellular unit (BMU). Oestrogen deficiency during growth is associated with reduced bone mass and increased leg length in males and females. Oestrogen deficiency during ageing may account for trabecular bone loss in men by increasing remodelling rate. There have been no anti-fracture efficacy studies done in Asian males. Studies on the pathophysiology of osteoporosis in males have given insight into the pathophysiology of osteoporosis in females. Similarly, collaborative research efforts between groups around the world will facilitate comparative studies in Asian and Caucasian communities. The results of this work will provide important insights into the pathophysiology of bone fragility in both groups.

Cut-off values determined for vertebral fracture by peripheral quantitative computed tomography in Japanese women

In spite of the benefits of bone mass measurement by dual-energy X-ray absorptiometry (DXA), the use of DXA has limitations. It is unable to assess a true bone density, and cannot discriminate between the trabecular and cortical bone compartments. Ultradistal radius bone density was measured using peripheral quantitative computed tomography (pQCT) to determine reference values for total bone density (BD), trabecular bone density (TBD), polar strength strain index (pSSI), total bone mineral content (BC), trabecular bone mineral content (TBC), cortical bone density (CBD), cortical bone mineral content (CBC) and polar cross-sectional moment of inertia (pCSMI) in the Japanese female population, and to ascertain the cut-off values of the measured indicators that could most efficiently discriminate osteoporotic subjects with vertebral fractures. A total of 5266 healthy Japanese women aged 20-89 years were included in this study to determine Japanese reference values. Additionally, 621 who had undergone radiographic examination of the thoracic and lumbar spine at the time of pQCT measurement were selected to determine the cut-off values of BD, TBD, pSSI and other indicators for vertebral fractures. All the healthy subjects were divided into 5 year age groups. The BD showed nonsignificant changes from the 20-24 year age group to the 45-49 year age group, and fell significantly thereafter. The TBD maintained a plateau until the 40-44 year group, which corresponds to the young adult mean (YAM) values of the lumbar spine, femoral neck and radius BMDs measured using DXA. The TBD decreased significantly thereafter. The pSSI did not change significantly from the 20-24 year age group to the 45-49 year age group, and decreased slightly in the 50-54 year age group and markedly after 55-59 years. The cut-off values for the discrimination of vertebral fractures were obtained by the calculation of sensitivities, specificities and the area under the curves obtained using age-adjusted receiver operating characteristics (ROC) analysis. Odds ratios and 95% confidence limits (CL) were calculated using age-adjusted logistic analysis. The cut-off values for vertebral fractures, the area under the ROC curves (AUC) and odds ratios were 270.1 mg/cm3 (-2.2 SD, 66.6% of YAM), 0.689+/-0.025, 2.10 (1.63, 2.70) for BD, 104.8 mg/cm3 (-2.2 SD, 53.5% of YAM), 0.699+/-0.023, 2.17 (1.69, 2.77) for TBD and 192.8 mm3 (-1.9 SD, 59.8% of YAM), 0.631+/-0.028, 1.72 (1.34, 2.21) for pSSI, respectively. These findings suggest that ultradistal radius BMD measured using pQCT can be used to discriminate women with vertebral fractures.

Spinal trabecular bone loss and fracture in American and Japanese women

This study examined trabecular bone mineral density (BMD) in Japanese women with and without spinal fracture, and compared the results to American women with and without fracture. The quantitative computed tomography (QCT) systems used at the University of California, San Francisco (UCSF) and at Nagasaki University were cross-calibrated. Normative BMD was assessed with the K2HPO4 liquid phantom in 538 Americans aged 20-85 years, and with the B-MAS200 phantom in 577 Japanese aged 20-83 years. These BMD were adjusted for use with the Image Analysis solid phantom using the result of cross-calibration. The trabecular BMD in 111 postmenopausal American women (55 with fracture), and in 185 postmenopausal Japanese women (67 with fracture) were compared for investigation of the difference in BMD values relative to fracture status. The absolute BMD values in Japanese were lower than those in Americans, and the differences were greater with advancing age. The magnitude of the BMD difference was 8.6, 20.5, 38.1 mg/cm3 in women aged 20-24 years, 40-44 years, 60-64 years, respectively. In premenopausal women, BMD began to decrease at the age of 20 in Japanese, whereas the peak bone mass was maintained until the age of 35 in the American women. In immediate postmenopausal women, BMD significantly decreased in both populations. In later postmenopausal women, BMD significantly decreased with age in the Japanese women but decreased less rapidly in the American women. The aging decrease of BMD was 1.4% and 2.2% per year in the later postmenopausal American and Japanese women, respectively. The fracture threshold is considered to be lower in Japanese women. However, the BMD difference between American and Japanese women with fracture was similar to that without fracture. The Z-scores of fracture subjects versus controls were 2.9 in American and 1.8 in Japanese women. In conclusion, Japanese women were found to have a lower BMD and lower fracture threshold than American women. The significant decrease of spinal trabecular BMD in late postmenopause is potentially responsible for the higher prevalence of spinal fracture in Japanese women.

Vertebral fracture prevalence in women in Hiroshima compared to Caucasians or Japanese in the US

BACKGROUND

Although vertebral fractures are very common among elderly Caucasian women, no studies have compared the prevalence to that among Asian populations. Any observed differences in prevalence might lead to the identification of important environmental and/or genetic factors. We therefore compared the prevalence of vertebral fractures among US Caucasians to native Japanese and Japanese immigrants in Hawaii using a standardized approach.

METHODS

Spinal radiographs of women aged > 50 years were obtained from native Japanese in Hiroshima, Japanese-Americans in Hawaii, and North American Caucasians in Minnesota between 1982 and 1991. Fractures were defined as vertebral heights > 3 standard deviations (SD) below the vertebra-specific mean.

RESULTS

Compared to Japanese-Americans, odds ratios (OR) and 95% confidence intervals (CI) for prevalent vertebral fractures were 1.8 (95% CI: 1.3-2.5) for native Japanese women and 1.5 (95% CI: 1.1-2.1) for Minnesota Caucasians. The OR tended to be higher when comparing the prevalence of two or more fractures per person: OR = 3.2 (95% CI: 2.0-5.3) for native Japanese and OR = 1.9 (95% CI: 1.2-3.2) for Minnesota Caucasians. Similar results were observed for native Japanese using a fracture definition of > or = 4 SD below the mean, but the OR for Caucasians was reduced to 1.2 (95% CI: 0.6-2.3).

CONCLUSION

The observation that, among these three populations, hip fracture incidence is lowest but spine fracture prevalence is greatest among native Japanese suggests that different risk factors may be responsible.

Vertebral dimension measurements improve prediction of vertebral fracture incidence

We investigated the independent contributions of vertebral size and shape, bone density, and existing fractures for predicting the risk of new vertebral fractures among postmenopausal Japanese-American women in Hawaii. Baseline measurements of bone density at the distal and proximal radius and the calcaneus were obtained in 1981, and at the lumbar spine in 1984. Incident fractures were documented on serial radiographs during an average of 8.0 years of follow up of 840 women. A positive difference of 1 standard deviation in vertebral depth increased the risk of new vertebral fractures by approximately 1.3-fold (95% confidence interval = 1.03, 1.66) after controlling for bone density and prevalent fractures. A combination of large vertebral depth (above the 66th percentile) and low bone density (below the 33rd percentile) increased fracture risk approximately six times compared to women with high bone density (above the 66th percentile) and small vertebral depth (below the 33rd percentile). We conclude that combining information about vertebral depth, bone density, and prevalent fracture appears to be better for predicting new fractures than any single variable alone.

Age-dependent vitamin D status and vertebral condition of white women living in Curaçao (The Netherlands Antilles) as compared with their counterparts in The Netherlands

Plasma vitamin D metabolites and parathyroid hormone concentrations of two groups of white women, aged 26-46 and 63-83 y, in Curaçao were studied to evaluate the effect of yearlong abundant sunlight on frequency of vertebral compression fractures in elderly women. 25-Hydroxyvitamin D of the younger group (median, 116 nmol/L) was higher than that of the older group (75 nmol/L). Both groups had higher 25-hydroxyvitamin D compared with approximately age-matched counterparts in The Netherlands during autumn and winter (50 and 25 nmol/L, respectively). Similar differences were found for 1,25-dihydroxyvitamin D, although to a lesser extent. Parathyroid hormone concentrations of older women in Curaçao (4.3 pmol/L) were higher than those of the younger women (2.3 pmol/L). Roentgenographic analyses of the spines of the older women did not show vertebral compression fractures commonly encountered in women living at higher latitudes. Uninterrupted high plasma concentrations of vitamin D metabolites may reduce vertebral compression fractures in postmenopausal white women.

Vertebral dimension differences between Caucasian populations, and between Caucasians and Japanese

Various criteria have been proposed for using vertebral measurements to identify vertebral fractures. It is known that the normal distributions of vertebral heights and ratios vary with location within the spine. However, very little is known regarding the degree to which differences in these parameters may exist between populations. We report the vertebra-specific distributions of vertebral dimensions and ratios for Japanese-Americans, and compare these values to published data for Caucasians. The mean Japanese vertebral heights were 1 to 2 mm shorter than Caucasians, which may be due in part to the shorter stature of Japanese. However, differences in mean values were also observed between Caucasian populations. Furthermore, anterior/posterior vertebral height ratios differed between Caucasian studies, and between races. Additional studies are needed to determine to what degree these differences are due to technical and biological factors before criteria derived from one population can be used for identifying vertebral fractures in other populations of the same, or different, race.

The incidence of thoracic vertebral fractures in a Japanese population, Hiroshima and Nagasaki, 1958-86

The incidence of thoracic vertebral fractures (TVF) in a Japanese population of 14,607 individuals from Hiroshima and Nagasaki was determined by sex, age, birth cohort, and exposure to atomic bomb radiation. The diagnosis of TVF was based on lateral chest radiographs made from 1 July 1958 to 28 February 1986. The subjects, who were born between 1880 through 1939, were categorized by sex into 10-year birth cohorts. TVF incidence increased by a factor of 1.7 in all birth cohorts with each 10-year increase in age in females, but did not increase with age in males. The incidence was significantly lower in the younger birth cohorts in both sexes. The incidence declined by a factor of 0.5 in males and 0.6 in females for each 10-year decrease in the year of birth. TVF incidence did not differ between the cities, and no correlation with atomic bomb radiation exposure was demonstrated.