Racial differences in bone mineral density in older men

Lifetime Smoking History and Prevalence of Osteoporosis and Low Bone Density in U.S. Adults, National Health and Nutrition Examination Survey 2005-2010

Background: Osteoporosis is common among older adults. Women are more likely to have osteoporosis than men. The prevalence varies with race/ethnicity, with the highest prevalence observed among non-Hispanic, Asian women. Prior studies identified a negative association between smoking and bone mineral density (BMD). The association between smoking and osteoporosis has not been investigated according to race/ethnicity. Materials and Methods: We included 4,226 U.S. adults aged 50 years or older with complete information on smoking history, BMD, and other independent variables from the 2005-2010 National Health and Nutrition Examination Surveys. Design-based multinomial logistic regression was utilized to estimate prevalence odds ratios (POR) of osteoporosis (T-score ≤ -2.5) and of low bone density (T-score between -1.0 and -2.5) in relation to lifetime smoking pack-years, stratified by sex and race/ethnicity. Results: Participants were 61.5 (standard error 0.21) years old on average and 48% women (n = 2,027). Among women, a smoking history ≥30 pack-years was positively associated with osteoporosis (POR: 2.40; 95% confidence interval [CI]: 1.42-4.06). Similar POR were observed among non-Hispanic White, non-Hispanic Black, and Mexican American women. However, POR for ≥30 pack-years and low bone density were positive but not statistically significant. Among men, null associations of smoking history, osteoporosis, and low bone density were observed, except for a positive association of ≥30 pack-years and low bone density among non-Hispanic Black men. Conclusion: Osteoporosis was twice as prevalent among women who smoked ≥30 pack-years than among women who never smoked, regardless of race/ethnicity. Smoking history and osteoporosis were not associated among men.

Racial and Ethnic Disparities in Bone Health and Outcomes in the United States

Osteoporosis is a bone disease classified by deterioration of bone microarchitecture and decreased bone strength, thereby increasing subsequent risk of fracture. In the United States, approximately 54 million adults aged 50 years and older have osteoporosis or are at risk due to low bone mass. Osteoporosis has long been viewed as a chronic health condition affecting primarily non-Hispanic white (NHW) women; however, emerging evidence indicates racial and ethnic disparities in bone outcomes and osteoporosis management. The primary objective of this review is to describe disparities in bone mineral density (BMD), prevalence of osteoporosis and fracture, as well as in screening and treatment of osteoporosis among non-Hispanic black (NHB), Hispanic, and Asian adults compared with NHW adults living on the US mainland. The following areas were reviewed: BMD, osteoporosis prevalence, fracture prevalence and incidence, postfracture outcomes, DXA screening, and osteoporosis treatments. Although there are limited studies on bone and fracture outcomes within Asian and Hispanic populations, findings suggest that there are differences in bone outcomes across NHW, NHB, Asian, and Hispanic populations. Further, NHB, Asian, and Hispanic populations may experience suboptimal osteoporosis management and postfracture care, although additional population-based studies are needed. There is also evidence that variation in BMD and osteoporosis exists within major racial and ethnic groups, highlighting the need for research in individual groups by origin or background. Although there is a clear need to prioritize future quantitative and qualitative research in these populations, initial strategies for addressing bone health disparities are discussed. © 2021 American Society for Bone and Mineral Research (ASBMR).

Hip geometry in hip fracture patients in Greenland occurring over a 7.7-year period

Background

Hip geometry influences hip fracture risk. Hip fractures are common, and they are associated with pain, disability, premature death and marked costs on society. Osteoporotic fractures are frequent in Arctic populations and increase with advancing age in this society with a steep rise in life expectancy. Greenland Inuit is a distinct ethnic group, and data on hip geometry is missing. We thus aimed to describe hip geometry in 7.7 years of consecutive hip fracture patients in Greenland.

Methods

We evaluated collodiaphysial angle, femoral neck length, the outer and inner diameter of the femur at 2 and 5 centimetres below the centre of the lesser trochanter and the cortical thickness from pelvic and hip radiographs in all patients operated in Greenland over 7.7 years. We included all 84 patients with one non-fractured hip visible for geometric analysis. Analyses were conducted in duplicate.

Results

We found a collodiaphysial angle of 134.8/132.6^o in men/women (p = 0.06) and a femoral neck length of 38.0/33.9 mm in men/women (p = 0.001). Cortical thickness was affected by sex in the adjusted analysis (p < 0.001). Cortical thickness index at 5 cm below the centre of the lesser trochanter decreased with age (p = 0.026) and may be influenced by height (2 cm below the centre of the lesser trochanter, p = 0.053).

Conclusion

Our findings differed from European data and suggest a delicate balance in hip geometry in Arctic populations. Ethnic peculiarities influence the structure of the hip and may influence fracture risk. A focus on hip geometry and risk factors for osteoporotic fractures in Arctic populations is warranted.

Genome-wide association study of vitamin D concentrations and bone mineral density in the African American-Diabetes Heart Study

Relative to European Americans, African Americans have lower 25-hydroxyvitamin D (25OHD) and vitamin D binding protein (VDBP) concentrations, higher 1,25-dihydroxyvitamin D (1,25(OH)₂D₃) concentrations and bone mineral density (BMD), and paradoxically reduced burdens of calcified atherosclerotic plaque (subclinical atherosclerosis). To identify genetic factors contributing to vitamin D and BMD measures, association analysis of >14M variants was conducted in a maximum of 697 African American-Diabetes Heart Study participants with type 2 diabetes (T2D). The most significant association signals were detected for VDBP on chromosome 4; variants rs7041 (β = 0.44, SE = 0.019, P = 9.4x10^-86) and rs4588 (β = 0.17, SE = 0.021, P = 3.5x10^-08) in the group-specific component (vitamin D binding protein) gene (GC). These variants were found to be independently associated. In addition, rs7041 was also associated with bioavailable vitamin D (BAVD; β = 0.16, SE = 0.02, P = 3.3x10^-19). Six rare variants were significantly associated with 25OHD, including a non-synonymous variant in HSPG2 (rs116788687; β = -1.07, SE = 0.17, P = 2.2x10^-10) and an intronic variant in TNIK (rs143555701; β = -1.01, SE = 0.18, P = 9.0x10^-10), both biologically related to bone development. Variants associated with 25OHD failed to replicate in African Americans from the Insulin Resistance Atherosclerosis Family Study (IRASFS). Evaluation of vitamin D metabolism and bone mineral density phenotypes in an African American population enriched for T2D could provide insight into ethnic specific differences in vitamin D metabolism and bone mineral density.

Differences in geometric strength at the contralateral hip between men with hip fracture and non-fractured comparators

Older men sustain excess bone mineral density (BMD) declines after hip fracture; however, BMD provides no information on mechanical structure and strength. The aim was to assess whether changes in hip bone geometry in older men after hip fracture differ than that expected with aging. Two cohorts were used: Baltimore Hip Studies 7th cohort (BHS-7) and Baltimore Men's Osteoporosis Study (MOST). The sample (N = 170) included older Caucasian men with hip fracture that were propensity score matched (1:1) to community-dwelling non-fractured comparators. Hip Structural Analysis (HSA) calculated aerial BMD and metrics of bone structural strength: cross-sectional bone area (CSA), cortical outer diameter (OD), section modulus (SM), and centroid position (CP). Mixed-effect models estimated changes in HSA parameters and adjusted robust regression models evaluated between-cohort differences in annual percent change at the narrow neck (NN), intertrochanteric (IT), and femoral shaft (FS). Hip fracture was associated with statistically greater declines in NN CSA (β = -2.818; 95% CI: -3.300%, -2.336%), SM (β = -1.896%; 95% CI: -2.711%, -1.080%) and CP (β = -0.884%; 95% CI: -0.889%, -0.880%) and significantly larger increases in NN OD (β = 0.187%; 95% CI: 0.185%, 0.190%). Differences in IT HSA parameters were like the NN but larger in magnitude, while there were favorable changes in FS geometry where fragility fractures are rare. Findings indicate there are declines in bone structure and strength at the NN and IT regions of the proximal femur in older men during hip fracture recovery that far exceed what occurs during normal aging.

Racial Variation in the Relationship of Glycemic Control with Fracture Risk in Elderly Patients with Diabetes

We investigated racial variation in glycemic control (glycated hemoglobin A1c [HbA1c]) with fracture risk in geriatric patients with diabetes. Compared to an HbA1c of 7.0-7.9% [53-63 mmol/mol], HbA1c ≥9.0% [≥75 mmol/mol] was associated with increased fracture risk among Blacks and those of Unknown race only. This increase was attenuated in Blacks after accounting for the relative frequency of patient-provider interaction.

Age estimation using bone mineral density in South Africans

The use of bone mineral density (BMD) to predict age-at-death in skeletal remains provides a usable alternative to other methods because the values obtained are not observer-dependent. The aim of this study was to investigate the usability of BMD to estimate age in South African populations, and to assess inter-population variation and sex-specific differences in BMD values from the proximal end of the femur. In order to estimate age, regression analysis was done for the construction of population dependent formulae. The sample comprised of a total of 123 femora of black and white South Africans. DXA scans were performed using the Hologic Discovery system. Data analysis was done by employing independent-samples t-tests and correlation/regression analyses. The results indicated a statistically significant difference between black and white South Africans. Male groups were also significantly different from one another, but black and white females showed no significant differences. Linear regression analysis revealed a significant correlation between BMD values and age for the white population and the combined sample, but not for the black population. Bootstrapping were employed to confirm validity of the results. In conclusion, this study showed that the use of DXA measurements of the femur for estimating age may be used for the estimation of age-at-death in white South Africans, but more research is needed to better understand the relationship between bone mineral density and age in black South Africans.

Nonalcoholic fatty liver disease with elevated alanine aminotransferase levels is negatively associated with bone mineral density: Cross-sectional study in U.S. adults

Background

Nonalcoholic fatty liver disease (NAFLD) has been reported to have a negative effect on bone mineral density (BMD) in Asian populations. Whether such an association exists in Western populations is less clear.

Methods

This cross-sectional analysis of data from NHANES III, a United States national health survey conducted from 1988 to 1994, included 6089 participants aged 40–75 years, selected after excluding people with hepatitis virus serology, elevated alcohol consumption, decreased renal function, or steroid use, and pregnant females. The main outcome, BMD at the femoral neck, was measured using dual-energy X-ray absorptiometry. The primary exposure, NAFLD, was defined as moderate or severe hepatic steatosis diagnosed using abdominal ultrasonography.

Result

After controlling for gender and menopausal status, race/ethnicity, age and body mass index, NAFLD was not significantly associated with BMD (beta coefficient: −0.006, 95%CI: −0.016, 0.003). A secondary analysis categorized participants with NAFLD according to their serum alanine aminotransferase (ALT) levels into high and normal ALT NAFLD groups, and compared these with the non-NAFLD group. NAFLD with higher levels of ALT was associated with lower levels of BMD (beta coefficient: −0.023, 95% CI: −0.044, −0.002).

Conclusion

This study showed a relationship between NAFLD with high ALT and lower BMD in the general U.S. population.

Competing Risks of Fracture and Death in Older Adults with Chronic Kidney Disease

OBJECTIVES

To examine whether chronic kidney disease (CKD) at any stage is associated with fracture risk after adjusting for competing mortality and to determine whether age or race modify the relationship between CKD and fracture risk.

DESIGN

Prospective cohort study.

SETTING

Department of Veterans Affairs (VA) national healthcare system.

PARTICIPANTS

Men receiving VA primary care aged 65 and older with no history of fracture or osteoporosis therapy (N = 712, 918).

MEASUREMENTS

We determined CKD stage from baseline estimated glomerular filtration rate (eGFR). Participants were followed for up to 10 years for occurrence of any fracture or death. We ascertained fractures and covariates from VA medical records and Medicare claims.

RESULTS

Of the 356,459 older veterans with CKD (defined as eGFR <60 mL/min per 1.73 m² ), 15.7% (n = 56,032) experienced a fracture, and 43.0% (n = 153,438) died over a median time at risk of 5.2 years. Veterans with CKD Stages 3 to 5 had a greater risk of death than those without CKD, which biased estimates from traditional survival models. Competing risk models showed that Stage 3 CKD was associated with greater hazard (adjusted subdistribution hazard ratio (sdHR) = 1.07, 95% confidence interval (CI) = 1.02-1.11) of fracture (than those without CKD) and a trend toward greater hazard for Stage 4 (sdHR = 1.07, 95% CI = 0.94-1.22) and Stage 5 (sdHR = 1.31, 95% CI = 0.97-1.77) CKD. Age, race, and bone mineral density did not modify the relationship between CKD and fracture risk.

CONCLUSIONS

In older male veterans, CKD, including Stage 3, is associated with a moderately greater fracture risk irrespective of age, race, or bone mineral density.

Comparison of bone mineral loss by combined androgen block agonist versus GnRH in patients with prostate cancer: A 12 month-prospective observational study

The multi-centre, prospective, observational study was designed to examine the efficacy of continuous combined androgen block (CAB) vs. GnRH agonist monotherapy in terms of bone mineral density (BMD) change during 12 months post-androgen deprivation therapy (ADT) in Asian prostate cancer patients. Multiple regression analysis and estimated the 10-year probability of major fractures among the patients with Fracture Risk Assessment Tool were conducted to investigate the underlying factors affecting BMD. Paired t-test to evaluate the change of BMD from baseline to 12 month, and two sample t-test to examine the difference of BMD changes were used between two groups. BMD significantly decreased in both the CAB and GnRH groups, with no group wise differences. The proportion of osteopenia or osteoporosis was slightly increased after the 12-month post-ADT. Ten-year probability of hip fracture and major osteoporotic fracture was approximately 3% and 5%, respectively. In conclusion, a significant decrease of BMD by 12-month ADT was observed without any differences between the two groups, whereas ADT-related BMD loss did not induce detrimental effects on bone health in terms of increased bone fracture risk. This was the first prospective study on BMD changes as a predictor of fracture during ADT in an Asian population.

Admixture mapping of serum vitamin D and parathyroid hormone concentrations in the African American-Diabetes Heart Study

Vitamin D and intact parathyroid hormone (iPTH) concentrations differ between individuals of African and European descent and may play a role in observed racial differences in bone mineral density (BMD). These findings suggest that mapping by admixture linkage disequilibrium (MALD) may be informative for identifying genetic variants contributing to these ethnic disparities. Admixture mapping was performed for serum 25-hydroxyvitamin D, 1,25-dihydroxyvitamin D, vitamin D-binding protein (VDBP), bioavailable vitamin D, and iPTH concentrations and computed tomography measured thoracic and lumbar vertebral volumetric BMD in 552 unrelated African Americans with type 2 diabetes from the African American-Diabetes Heart Study. Genotyping was performed using a custom Illumina ancestry informative marker (AIM) panel. For each AIM, the probability of inheriting 0, 1, or 2 copies of a European-derived allele was determined. Non-parametric linkage analysis was performed by testing for association between each AIM using these probabilities among phenotypes, accounting for global ancestry, age, and gender. Fine-mapping of MALD peaks was facilitated by genome-wide association study (GWAS) data. VDBP levels were significantly linked in proximity to the protein coding locus (rs7689609, LOD=11.05). Two loci exhibited significant linkage signals for 1,25-dihydroxyvitamin D on 13q21.2 (rs1622710, LOD=3.20) and 12q13.2 (rs11171526, LOD=3.10). iPTH was significantly linked on 9q31.3 (rs7854368, LOD=3.14). Fine-mapping with GWAS data revealed significant known (rs7041 with VDBP, P=1.38×10(-82)) and novel (rs12741813 and rs10863774 with VDBP, P<6.43×10(-5)) loci with plausible biological roles. Admixture mapping in combination with fine-mapping has focused efforts to identify loci contributing to ethnic differences in vitamin D-related traits.

Utility of DXA scanning and risk factors for osteoporosis in ankylosing spondylitis-A prospective study

BACKGROUND

Conventional DXA imaging of spine and hip to measure bone mineral density (BMD) has limitations in patients with ankylosing spondylitis (AS). We investigated the correlation of hip and spine BMD measurements in patients with AS to determine if hip DXA will prove clinically useful while avoiding the confounding effect of spinal disease. Also, we studied risk factors for osteoporosis (OP) and osteopenia in AS.

METHODS

We randomly identified patients from our validated AS registry ≥18 years of age who met the Modified New York Classification criteria for AS. BMD was measured and interpreted using ISCD 2007 guidelines and diagnosis of OP was based on WHO criteria. ESR, CRP, urinary N-telopeptide, and 25-hydroxy vitamin D were also measured. Correlation between the BMD (total hip and/or femoral neck) and lumbar spine was calculated. Statistical comparisons between the 2 sites, lumbar spine (AP) and hip (total hip and or femoral neck) were made using Bowker's test for symmetry and kappa statistics. Chi-square and odds ratio using logistic regression were used to assess the association of the purported risk factors for OP in these patients.

RESULTS

Frequency of OP among AS patients ≥50 years of age was 23%, and that of osteopenia was 41%. Among patients <50 years of age, the frequency of low bone mass for expected age (Z-score ≤-2.0) was 14.7%. There was moderate correlation (ρ = 0.59) and a fair agreement (κ = 0.26; 95% CI: 0.10-0.42) between the lowest T-values of hip and lumbar spine (AP view). OP was significantly associated with elevated CRP level [OR = 4.2 (95% CI: 1.13-15.9), p < 0.03] and African American race [OR = 7.2 (95% CI: 1.18-44.99), p < 0.03].

CONCLUSION

Our results demonstrated a moderate correlation and fair agreement between the T-scores of hip and the lumbar spine (AP view) in patients with AS, suggesting that DXA of the hip and the lumbar spine (AP view) may both be useful for OP and osteopenia screening in patients with AS without fused spines. We confirm the previous reports of an association of elevated CRP level with an increased risk of OP in patients with AS, but this is the first study to demonstrate that African American patients with AS may be at a higher risk of developing OP compared to Caucasians.

Vitamin D Associations With Renal, Bone, and Cardiovascular Phenotypes: African American-Diabetes Heart Study

CONTEXT

Vitamin D binding protein (DBP) is an important determinant of bioavailable vitamin D (BAVD) and may provide clues to racial variation in osteoporosis and atherosclerosis.

OBJECTIVE

The objective was to assess relationships between DBP, BAVD, 25-hydroxyvitamin D (25OHD), and 1,25 di-hydroxyvitamin D (1,25OH2D) with kidney, bone, adipose, and atherosclerosis phenotypes in African Americans with type 2 diabetes.

DESIGN

Cross-sectional (N = 545) and longitudinal (N = 288; mean 5.1 ± 0.9-year follow-up) relationships between vitamin D concentrations with renal phenotypes, vertebral bone mineral density, aorto-iliac, coronary artery, and carotid artery calcified plaque (CP), and adipose tissue volumes were studied.

SETTING

African American-Diabetes Heart Study.

PATIENTS

Participants were 56.7% female with mean ± standard deviation (sd) age 55.6 ± 9.6 years, diabetes duration 10.3 ± 8.2 years, and eGFR 90.9 ± 22.1 ml/min/1.73 m(2).

INTERVENTIONS

None.

MAIN OUTCOMES AND MEASURES

Associations tested between vitamin D and the previously mentioned phenotypes adjusting for age, sex, African ancestry proportion, diabetes duration, statins, smoking, changes in estimated glomerular filtration rate, body mass index, hemoglobin A1c, and blood pressure.

RESULTS

1,25OH2D was inversely associated with change in coronary artery CP (parameter estimate [β] -0.005, standard error [SE] 0.002; P = .037), with a trend for change in carotid artery CP (β -0.007, SE 0.004; P = .074). Further adjustment for renin-aldosterone-system blockade revealed inverse association between 1,25OH2D and change in albuminuria (β -0.004, SE 0.002; P = .037). DBP, BAVD, and 25OHD did not associate significantly with changes in albuminuria, CP, or bone mineral density. BAVD was inversely associated with visceral, subcutaneous, intermuscular, and pericardial adipose volumes.

CONCLUSIONS

In contrast to BAVD and 25OHD, only 1,25OH2D levels were significantly and inversely associated with changes in subclinical atherosclerosis and albuminuria in African Americans, suggesting potential beneficial effects.

Cardiometabolic and skeletal risk factors in black men with prostate cancer starting androgen deprivation therapy

BACKGROUND

Androgen deprivation therapy (ADT) for prostate cancer (PCa) is associated with multiple metabolic complications, previously predominantly evaluated in the white population.

METHODS

A chart-based retrospective review was conducted on black patients with PCa, considered for ADT, from September 2007 to July 2010. Baseline data were collected on body mass index (BMI), vitamin-D status, bone mineral density (BMD), dyslipidemia and diabetes. Overweight and obesity were classified as BMI ≥ 25 and BMI ≥ 30, respectively. Vitamin-D sufficiency was defined as levels ≥30 ng/mL, insufficiency as <30 ng/mL and deficiency as ≤20 ng/mL. Osteopenia was defined as T scores between -1 to -2.5 and osteoporosis when T scores ≤-2.5.

RESULTS

Of the initial cohort of 130 black men, 111 (85.4%) patients underwent ADT. At baseline, average BMI was 28.1 ± 5.9 with 43.3% of men being overweight and 30.8% obese. More than one-third of the patients had pre-existing dyslipidemia while 28.8% were diabetics. 50% were vitamin-D deficient while 41% had low bone mass.

CONCLUSIONS

Black men with PCa presenting for consideration of ADT have a high prevalence of existing metabolic risk factors. Close monitoring of this patient population is needed during ADT to prevent and treat metabolic complications.

A single nucleotide polymorphism in osteonectin 3' untranslated region regulates bone volume and is targeted by miR-433

Osteonectin/SPARC is one of the most abundant noncollagenous extracellular matrix proteins in bone, regulating collagen fiber assembly and promoting osteoblast differentiation. Osteonectin-null and haploinsufficient mice have low-turnover osteopenia, indicating that osteonectin contributes to normal bone formation. In male idiopathic osteoporosis patients, osteonectin 3' untranslated region (UTR) single-nucleotide polymorphism (SNP) haplotypes that differed only at SNP1599 (rs1054204) were previously associated with bone mass. Haplotype A (containing SNP1599G) was more frequent in severely affected patients, whereas haplotype B (containing SNP1599C) was more frequent in less affected patients and healthy controls. We hypothesized that SNP1599 contributes to variability in bone mass by modulating osteonectin levels. Osteonectin 3' UTR reporter constructs demonstrated that haplotype A has a repressive effect on gene expression compared with B. We found that SNP1599G contributed to an miR-433 binding site, and miR-433 inhibitor relieved repression of the haplotype A, but not B, 3' UTR reporter construct. We tested our hypothesis in vivo, using a knock-in approach to replace the mouse osteonectin 3' UTR with human haplotype A or B 3' UTR. Compared with haplotype A mice, bone osteonectin levels were higher in haplotype B mice. B mice displayed higher bone formation rate and gained more trabecular bone with age. When parathyroid hormone was administered intermittently, haplotype B mice gained more cortical bone area than A mice. Cultured marrow stromal cells from B mice deposited more mineralized matrix and had higher osteocalcin mRNA compared with A mice, demonstrating a cell-autonomous effect on differentiation. Altogether, SNP1599 differentially regulates osteonectin expression and contributes to variability in bone mass, by a mechanism that may involve differential targeting by miR-433. This work validates the findings of the previous candidate gene study, and it assigns a physiological function to a common osteonectin allele, providing support for its role in the complex trait of skeletal phenotype. © 2014 American Society for Bone and Mineral Research.

Rates of and risk factors for trabecular and cortical BMD loss in middle-aged and elderly African-ancestry men

Low trabecular (Tb) and cortical (Ct) volumetric BMD (vBMD) are related to increased fracture risk, but little is known about the patterns and correlates of Tb and Ct vBMD loss with aging. We examined the rates of change in total, Tb.vBMD, and Ct.vBMD at the radius and tibia, and identified factors associated with vBMD loss among 1569 men of African descent aged 40 years and older. Quantitative computed tomography was used to measure vBMD 6 years apart. The annualized rate of loss in Tb.vBMD was significant at the radius (-0.047%/yr, p = 0.016) but not at the tibia. At the radius, a significant loss of Tb.vBMD was observed in men aged 40 to 49 years that appeared to be attenuated and not statistically significant among older age men. In contrast, the decline in Ct.vBMD was similar at both skeletal sites (-0.254 to -0.264%/yr, p < 0.0001) and was consistent across all age groups. Positive associations were found for vBMD changes with body weight (all but radius Ct.vBMD) and diabetes (Ct.vBMD only), whereas negative associations were found with hypertension (all but radius Tb.vBMD), smoking (Ct.vBMD only), and androgen deprivation therapy (cortical vBMD only). Trabecular and cortical vBMD loss appears to follow different patterns among middle- and older-aged men of African ancestry. Factors associated with the decline in vBMD also varied by compartment and anatomical site. Additional studies are needed to better understand the physiological mechanisms underlying early BMD loss among African-ancestry men.

The impact of uric acid on long-term mortality in patients with asymptomatic carotid atherosclerotic disease

BACKGROUND

Serum uric acid (SUA) has been discussed to be related to cardiovascular (CV) disease and outcome. We investigated whether levels of SUA predict long-term mortality in neurologically asymptomatic patients with carotid atherosclerotic disease.

METHODS

We prospectively studied 959 consecutive patients with carotid atherosclerosis as evaluated by duplex Doppler sonography for all-cause and CV death, respectively.

RESULTS

During a median follow-up time of 6.3 years (interquartile range [IQR], 5.4-7.1 years), 246 deaths (25.7%), including 160 CV deaths (16.7%), were recorded. Median baseline SUA levels were 5.9 mg/dL (IQR, 5.0-7.0 mg/dL). SUA was significantly associated with all-cause death and CV death. Adjusted hazard ratios (HRs) for an increase of 1 mg/dL of SUA levels were 1.12 (95% confidence interval [CI], 1.04-1.21; P = .003) and 1.20 (95% CI, 1.11-1.30; P < .001) for all-cause and CV death, respectively. Quartiles of SUA levels showed a significant association with CV mortality (log-rank P = .002). For CV death, adjusted HRs for quartiles of increasing SUA levels were 1.45 (95% CI, .87-2.43), 1.44 (95% CI, .85-2.46), and 2.26 (95% CI, 1.36-3.76; P < .01), compared with the lowest quartile, respectively. Patients with baseline carotid stenosis of more than 50% and/or increased levels of SUA (≥median) had an approximately 2-fold increase in risk of (CV) death, compared with patients with carotid narrowing of less than 50% and/or SUA levels less than the median (P < .001).

CONCLUSIONS

Levels of SUA represent independent predictors for CV mortality in a cohort of patients with asymptomatic carotid atherosclerosis.

Racial/ethnic and socioeconomic differences in bone loss among men

As men age, they lose bone and are susceptible to fracture. Despite having lower fracture rates than women, men have worse fractures than women do. Racial/ethnic and socioeconomic status (SES) disparities in fracture rates exist, yet data on rates of bone loss by race/ethnicity and SES among men are limited. We examined annualized percentage change in bone mineral density (%ΔBMD) at the hip (N = 681), spine (N = 663), and forearm (N = 636) during 7 years of follow-up among men aged 30-79 years at baseline. Multivariable models tested whether race/ethnicity, income, or genetic ancestry predicted annualized %ΔBMD after controlling for an extensive set of covariates. Annualized %ΔBMD ranged from -0.65(0.04)% (femoral neck) to +0.26(0.03)% (1/3 distal radius), and changes were consistent across age groups with the exception of the ultradistal radius, where annualized declines increased with age. Neither self-identified race/ethnicity nor genetic ancestry were associated with annualized %ΔBMD. In contrast, income was strongly associated (dose-response) with annualized %ΔBMD at total hip (independent of confounders, self-identified race/ethnicity, and genetic ancestry). Fully adjusted least-square mean change in annualized %ΔBMD at the total hip were -0.24(0.12)% and -0.16(0.06)% steeper among men with low and moderate incomes, respectively, than among men with higher incomes (overall p = 0.0293). Results show a linear decline in bone that begins relatively early in life among men, that rates of bone loss do not vary with race/ethnicity (self-identified or "objectively" measured), and that income plays an important role in relation to bone loss at the hip. These data suggest that fracture risk in men may be driven in part by income-related differences in bone loss, but also, that the known higher fracture risk among white men is not the result of racial/ethnic differences in bone loss, but rather, early life exposures that lead to attainment of higher peak bone mass among minorities.

Bone density testing among prostate cancer survivors treated with androgen-deprivation therapy

BACKGROUND

Androgen-deprivation therapy (ADT) causes bone loss and fractures. Guidelines recommend bone density testing before and during ADT to characterize fracture risk. The authors of the current report assessed bone density testing among men who received ADT for ≥ 1 year.

METHODS

Surveillance, Epidemiology, and End Results/Medicare data were used to identify 28,960 men aged > 65 years with local/regional prostate cancer diagnosed from 2001 to 2007 who were followed through 2009 and who received ≥ 1 year of continuous ADT. Bone density testing was documented in the 18-month period beginning 6 months before ADT initiation. Logistic regression was used to identify the factors associated with bone density testing.

RESULTS

Among men who received ≥ 1 year of ADT, 10.2% had a bone density assessment from 6 months before starting ADT through 1 year after. Bone density testing increased over time (14.5% of men who initiated ADT in 2007-2008 vs 6% of men who initiated ADT in 2001-2002; odds ratio for 2007-2008 vs 2001-2002, 2.29; 95% confidence interval, 1.83-2.85). Less bone density testing was observed among men aged ≥ 85 years versus men ages 66 to 69 years (odds ratio, 0.76; 95% confidence interval, 0.65-0.89), among black men versus white men (odds ratio, 0.72; 95% confidence interval, 0.61-0.86), and among men in areas with lower educational attainment (P < .001). Men who visited a medical oncologist and/or a primary care provider in addition to a urologist had higher odds of testing than men who only consulted a urologist (P < .001).

CONCLUSIONS

Few men who received ADT for prostate cancer underwent bone density testing, particularly older men, black men, and those living in areas with low educational attainment. Visiting a medical oncologist was associated with increased odds of testing. Interventions are needed to increase bone density testing among men who receive long-term ADT. Data on bone density testing for nonmilitary populations of prostate cancer survivors in the United States who have received long-term androgen-deprivation therapy (ADT) have not been published. The current analysis of Surveillance, Epidemiology, and End Results/Medicare data suggests that few prostate cancer survivors who receive long-term ADT undergo bone density testing; and several key populations, including African Americans and older men, have considerably lower rates of bone density screening.

Bone Mineral Density as a Predictor of Atherosclerosis and Arterial Wall Stiffness in Obese African-American Women

Bone demineralization is associated with higher cardiovascular event rates, possibly due to vascular calcification and accelerated atherosclerosis. African-Americans have less bone loss and less calcium content within atherosclerotic plaques. However, whether loss of bone mass is related to atherosclerosis has not been examined in African-Americans. The objective of this study was to evaluate possible associations between bone mineral density (BMD), carotid intimal-medial thickness (CIMT), and arterial stiffness. We studied 100 obese African-American women (BMI: 26.6 ± 6.2; age: 63 ± 14 years) referred for BMD estimation by dual-energy X-ray absorptiometry scan. BMD (g/cm(2)) was obtained at the lumbar spine (L1-L4), femoral neck, and total hip. Arterial stiffness was evaluated by the heart rate-corrected augmentation index (AI@75) and pulse wave velocity (PWV) using applanation tonometry. CIMT was measured by vascular ultrasound. Mean CIMT, AI@75, and PWV were 0.72 ± 0.14 mm, 28.8 ± 9.0%, and 8.9 ± 1.6 m/s, respectively. Mean BMD values at the lumbar spine, femoral neck, and hip were 0.96 ± 0.19, 0.80 ± 0.16, and 0.91 ± 0.17 g/cm(2). Older subjects had higher CIMT (r = 0.61, p < 0.001) and AI@75 (r = 0.42, p < 0.001). There was a significant correlation between AI@75 and CIMT (r = 0.45, p < 0.001). BMD was negatively correlated with AI@75 (lumbar: r = -0.22, p = 0.03; femoral neck: r = -0.24, p = 0.01; hip: r = -0.21, p = 0.03). BMD was unrelated to CIMT (lumbar: r = -0.09, p = 0.42; femoral neck: r = -0.15, p = 0.17; hip: r = -0.13, p = 0.23). On multivariate analysis, age (p < 0.001), hypertension (p = 0.02), and lumbar BMD (p = 0.01, R(2) = 0.30) were independent predictors of increased AI@75 after adjusting for age, height, and cardiovascular risk factors. These findings were unchanged upon substitution of femoral neck BMD (p = 0.05, R(2) = 0.28) into the model. There was a trend with hip BMD (p = 0.06, R(2) = 0.28) in the regression model. Age-matched comparison between normal BMD (n = 25) and osteoporotic patients (n = 34) demonstrated a significant difference in AI@75 (26.6 ± 8.9 vs. 31.6 ± 9.1%, p = 0.04). In summary, women with lower BMD had increased arterial stiffness. There was no relationship between BMD and atherosclerosis. In conclusion, age, hypertension, and BMD are independent predictors of higher arterial stiffness. Vascular changes are related to bone mineral loss, suggesting lower BMD may increase cardiovascular risk in African-Americans.

Effect of race and genetics on vitamin D metabolism, bone and vascular health

The pathophysiology of chronic kidney disease-mineral and bone disorder accounts for an inverse relationship between bone mineralization and vascular calcification in progressive nephropathy. Inverse associations between bone mineral density (BMD) and calcified atherosclerotic plaque are also observed in individuals of European and African ancestry without nephropathy, suggesting a mechanistic link between these processes that is independent of kidney disease. Despite lower dietary calcium intake and serum 25-hydroxyvitamin D (25(OH)D) concentrations, African Americans have higher BMD and develop osteoporosis less frequently than do European Americans. Moreover, despite having more risk factors for cardiovascular disease, African Americans have a lower incidence and severity of calcified atherosclerotic plaque formation than do European Americans. Strikingly, evidence is now revealing that serum 25(OH)D and/or 1,25 dihydroxyvitamin D levels associate positively with atherosclerosis but negatively with BMD in African Americans; by contrast, vitamin D levels associate negatively with atherosclerosis and positively with BMD in individuals of European ancestry. Biologic phenomena, therefore, seem to contribute to population-specific differences in vitamin D metabolism, bone and vascular health. Genetic and mechanistic approaches used to explore these differences should further our understanding of bone-blood vessel relationships and explain how African ancestry protects from osteoporosis and calcified atherosclerotic plaque, provided that access of African Americans to health care is equivalent to individuals of European ethnic origin. Ultimately, in our opinion, a new mechanistic understanding of the relationships between bone mineralization and vascular calcification will produce novel approaches for disease prevention in aging populations.

Lumbar spine bone mineral density in US adults: demographic patterns and relationship with femur neck skeletal status

This analysis examines lumbar spine bone mineral density (BMD) of US adults from NHANES 2005-2008 by age, sex, and race/ethnicity. Prevalence of low spine BMD and agreement between the prevalence of low BMD at the spine and femur neck in older adults are also assessed.

INTRODUCTION

Lumbar spine BMD data from a representative sample of the US population have not been previously available.

METHODS

We used data from the National Health and Nutrition Examination Survey 2005-2008 to examine demographic patterns in lumbar spine BMD among US adults age ≥20 years and the prevalence of low lumbar spine BMD in adults age ≥50 years. Agreement between the prevalence of low BMD at the femur neck and spine in older adults was also assessed. Dual-energy X-ray absorptiometry was used to measure lumbar spine and femur neck BMD. World Health Organization definitions were used to categorize skeletal status as normal, osteopenia, or osteoporosis.

RESULTS

Compared to non-Hispanic whites, non-Hispanic blacks had higher and Mexican Americans had lower lumbar spine BMD. Lumbar spine BMD declined with age in women, but not in men. Approximately 4.7 million (10%) older US women and 1 million (3%) older men had lumbar spine osteoporosis in 2005-2008. Roughly one third of them differed in skeletal status at the spine and hip but most were normal at one site and osteopenic at the other. Only 3-10%, depending on sex, had osteoporosis at one skeletal site but not at the other skeletal site. Between 76% and 87% with discordant skeletal status had lumbar spine T-scores within 1 unit of the category threshold.

CONCLUSIONS

These findings suggest that measuring either the femur neck or the lumbar spine will correctly classify the majority of individuals who present for care as osteoporotic or not.

Racial differences in bone mineral density and fractures in men receiving androgen deprivation therapy for prostate cancer

PURPOSE

Whether race influences bone loss and fracture risk during androgen deprivation therapy for prostate cancer is unknown. Using data from a prospective clinical trial we compared bone mineral density and fracture between African-American and Caucasian men receiving androgen deprivation therapy.

MATERIALS AND METHODS

A total of 516 subjects were in the placebo group of a 2-year randomized placebo controlled fracture prevention trial, and were African-American (68) or Caucasian (448). We compared baseline characteristics, changes in bone mineral density and rates of new fractures between races.

RESULTS

Compared to Caucasian men, African-American men had higher baseline hip bone mineral density (mean ± SD 0.98 ± 0.15 vs 0.91 ± 0.15 gm/m(2), p = 0.001) and similar spine bone mineral density (1.09 ± 0.22 vs 1.11 ± 0.22, p = 0.51). There was no difference in prevalent vertebral fractures between African-American and Caucasian men (7.4% vs 15.0%, p = 0.13). The percentage change in hip bone mineral density at 2 years was similar between African-American and Caucasian men (mean ± SE -2.21% ± 0.59% vs -2.54% ± 0.26%, p = 0.65). Changes in bone mineral density of the lumbar spine were also similar between African-American and Caucasian men (-1.74% ± 0.69% vs -1.30% ± 0.33%, p = 0.64). No new vertebral fractures were reported in African-American men but 2 fractures were reported in Caucasian men.

CONCLUSIONS

In a clinical trial African-American men receiving androgen deprivation therapy for prostate cancer have a greater hip bone mineral density and tended to have fewer prevalent vertebral fractures than Caucasian men. Despite a lower baseline risk of osteoporosis and fracture, African-American men experience a decrease in bone mineral density similar to that of Caucasian men.

Accounting for racial/ethnic variation in bone mineral content and density: the competing influences of socioeconomic factors, body composition, health and lifestyle, and circulating androgens and estrogens

The relative importance of various contributors to racial/ethnic variation in BMC/BMD is not established. Using population-based data, we determined that body composition differences (specifically skeletal muscle and fat mass) are among the strongest contributors to these variations.

INTRODUCTION

Racial/ethnic variation in fracture risk is well documented, but the mechanisms by which such heterogeneity arises are poorly understood. We analyzed data from black, Hispanic, and white men enrolled in the Boston Area Community Health/Bone (BACH/Bone) Survey to determine the contributions of risk factors to racial/ethnic differences in bone mineral content (BMC) and density (BMD).

METHODS

In a population-based study, BMC, BMD, and body composition were ascertained by DXA. Socioeconomic status, health history, and dietary intake were obtained via interview. Hormones and markers of bone turnover were obtained from non-fasting blood samples. Multivariate analyses measured percentage reductions in estimated racial/ethnic differences in BMC/BMD, accompanying the successive removal of covariates from linear regression models.

RESULTS

Black men demonstrated greater BMC than their Hispanic and white counterparts. At the femoral neck, adjustment for covariables was sufficient to reduce these differences by 46% and 35%, respectively. While absolute differences in BMC were smaller at the distal radius than femoral neck, the proportionate reductions in racial/ethnic differences after covariable adjustment were comparable or greater. Multivariate models provided evidence that lean and fat mass, serum 25(OH)D, osteocalcin, estradiol, and aspects of socioeconomic status influence the magnitude of racial/ethnic differences in BMC, with lean and fat mass providing the strongest effects. Results for BMD were similar, but typically of lesser magnitude and statistical significance.

CONCLUSIONS

These cross-sectional analyses demonstrate that much of the racial/ethnic heterogeneity in measures of bone mass and density can be accounted for through variation in body composition, diet, and socio-demographic factors.

Optimizing screening for osteoporosis in patients with fragility hip fracture

BACKGROUND

Osteoporosis, the underlying cause of most hip fractures, is underdiagnosed and undertreated. The 2008 Joint Commission report Improving and Measuring Osteoporosis Management showed only an average of 20% of patients with low-impact fracture are ever tested or treated for osteoporosis. We developed an integrated model utilizing hospitalists and orthopaedic surgeons to improve care of osteoporosis in patients with hip fracture.

QUESTIONS/PURPOSES

Does our integrated model combining hospitalists and orthopaedic surgeons improve the frequency of evaluation for osteoporosis, screening for secondary causes, and patients' education on osteoporosis?

PATIENTS AND METHODS

Our Hospitalist-Orthopaedic Surgeon Integrated Model of Care was implemented in September 2009. We compared the rate of evaluation and treatment of osteoporosis in 140 patients admitted with fragility hip fracture at our institution before (70 patients) and after (70 patients) implementation of the care plan.

RESULTS

Evaluation of patients for osteoporosis was higher in the postimplementation group compared to the preimplementation group (89% versus 24%). Screening of patients for secondary causes of osteoporosis was also improved in the postimplementation group (89% versus 0%), as was the proportion of patients who received education for osteoporosis management (89% versus 0%).

CONCLUSION

Our model of integrated care by hospitalists and orthopaedic surgeons resulted in improvement in the evaluation for osteoporosis, screening for secondary causes of osteoporosis, and education on osteoporosis management in patients with hip fracture at our institution. This may have important implications for treatment of these patients.

LEVEL OF EVIDENCE

Level III, therapeutic study. See Guidelines for Authors for a complete description of levels of evidence.

Age-related decline in bone density among ethnically diverse older men

We compared rates of BMD decline in older men of diverse ethnic background. The rate of bone loss was statistically equivalent between men of African and Caucasian descent.

INTRODUCTION

Race differences in peak bone mineral density (BMD) are well established, but the magnitude of bone loss among non-white men has not been well characterized. Our objective was to compare and contrast the rates of decline in BMD with aging among older men of different race/ethnic groups.

METHODS

The rate of decline in hip BMD was measured by dual-energy X-ray absorptiometry (Hologic QDR-4500 W) with an average follow-up of 4.6 years in 3,869 Caucasian, 138 African American, 145 Asian, and 334 Afro-Caribbean men aged ≥ 65 years (Mean ages: 73 ± 5, 70 ± 4, 72 ± 5, 71 ± 5 years, respectively).

RESULTS

The annual rate of decline in BMD at the femoral neck was -0.32%, -0.42%, -0.09%, and -0.44%/year for Caucasian, African American, Asian, and Afro-Caribbean men, respectively (p < 0.05 for Caucasian versus Asian). Although men of African ancestry have higher peak BMD than Caucasians, rates of decline in BMD with aging appear to be statistically equivalent in our study. In contrast, Asian men experienced a slower rate of decline in BMD compared with Caucasians and African Americans.

CONCLUSION

More studies are needed to better define the natural history of and factors associated with bone loss among non-white men.

Generalized bone loss as a predictor of three-year radiographic damage in African American patients with recent-onset rheumatoid arthritis

OBJECTIVE

To examine the association between baseline bone mineral density (BMD) and radiographic damage at 3 years of disease duration in a longitudinal cohort of African Americans with recent-onset rheumatoid arthritis (RA).

METHODS

African American RA patients with a disease duration of <2 years (n = 141) were included in the study. All patients underwent baseline BMD measurements (femoral neck and/or lumbar spine) using dual x-ray absorptiometry. T scores were calculated using normative data from the general population of African Americans. Patients were categorized as having osteopenia/osteoporosis (T score less than or equal to -1) or as being healthy. Hand and wrist radiographs, obtained at baseline and at 3 years of disease duration, were scored using the modified Sharp/van der Heijde method. The association between baseline BMD and total radiographic score at 3 years of disease was examined using multivariable negative binomial regression.

RESULTS

At baseline, the mean age and the mean disease duration were 52.4 years and 14.8 months, respectively; 85.1% of the patients were women. The average total radiographic scores at baseline and at 3 years of disease were 2.4 and 5.7, respectively. In the final reduced multivariable model, adjusting for age, sex, anti-cyclic citrullinated peptide antibody positivity, and the presence of radiographic damage at baseline, the total radiographic score at 3 years disease in patients with osteopenia/osteoporosis of the femoral neck was twice that in patients with normal bone density, and the difference was statistically significant (P = 0.0084). No association between lumbar spine osteopenia/osteoporosis and radiographic score was found.

CONCLUSION

Our findings suggest that reduced generalized BMD may be a predictor of future radiographic damage and support the hypothesis that radiographic damage and reduced generalized BMD in RA patients may share a common pathogenic mechanism.

Correlates of trabecular and cortical volumetric bone mineral density of the radius and tibia in older men: the Osteoporotic Fractures in Men Study

Quantitative computed tomography (QCT) can estimate volumetric bone mineral density (vBMD) and distinguish trabecular from cortical bone. Few comprehensive studies have examined correlates of vBMD in older men. This study evaluated the impact of demographic, anthropometric, lifestyle, and medical factors on vBMD in 1172 men aged 69 to 97 years and enrolled in the Osteoporotic Fractures in Men Study (MrOS). Peripheral quantitative computed tomography (pQCT) was used to measure vBMD of the radius and tibia. The multivariable linear regression models explained up to 10% of the variance in trabecular vBMD and up to 9% of the variance in cortical vBMD. Age was not correlated with radial trabecular vBMD. Correlates associated with both cortical and trabecular vBMD were age (-), caffeine intake (-), total calcium intake (+), nontrauma fracture (-), and hypertension (+). Higher body weight was related to greater trabecular vBMD and lower cortical vBMD. Height (-), education (+), diabetes with thiazolidinedione (TZD) use (+), rheumatoid arthritis (+), using arms to stand from a chair (-), and antiandrogen use (-) were associated only with trabecular vBMD. Factors associated only with cortical vBMD included clinic site (-), androgen use (+), grip strength (+), past smoker (-), and time to complete five chair stands (-). Certain correlates of trabecular and cortical vBMD differed among older men. An ascertainment of potential risk factors associated with trabecular and cortical vBMD may lead to better understanding and preventive efforts for osteoporosis in men.

Correlates of trabecular and cortical volumetric BMD in men of African ancestry

QCT provides a measure of volumetric BMD (vBMD) and distinguishes trabecular from cortical bone. Few studies have determined the factors related to vBMD in men, especially among men of African heritage. This study evaluated the relationship of anthropometric, medical, and behavioral factors and vBMD in a population-based cohort of men of African ancestry (n = 1901) >or=40 yr of age who had undergone screening for prostate cancer for the first time. Trabecular and cortical vBMD were measured at the radius and tibia by pQCT. Multiple linear regression analysis identified age, height, body weight, cigarette smoking, history of diabetes, fracture, and prostate cancer as the independent correlates of vBMD. However, associations with several variables differed between cortical and trabecular vBMD and between the radius and tibia. Longitudinal studies are needed to gain a better understanding of the mechanisms underlying these differential associations that may show new insight into the etiology of trabecular and cortical bone loss in men.

Relative contributions of multiple determinants to bone mineral density in men

SUMMARY

Focus on individual risk factors for osteoporosis could allocate disproportionate attention to trivial relationships. We tested many recognized risk factors of osteoporosis for their association with bone mineral density (BMD) in multivariate models among men. Lean mass accounted for the most variance, with substantially less accounted for by demographic, strength, and health factors.

INTRODUCTION

Osteoporosis in men has gained recognition as a public health problem, generating an interest in the search for risk factors. Isolation of individual risk factors could allocate disproportionate attention to relationships that may be of limited consequence.

METHODS

The Boston Area Community Health/Bone (BACH/Bone) Survey is a population-based study of randomly selected community-dwelling men (age, 30-79 years). BMD and lean mass were measured by dual X-ray absorptiometry. Socioeconomic status, health history, and lifestyle factors were obtained via interview. Hormone levels and markers of bone turnover were obtained from non-fasting blood samples. Multivariate analyses measured relative contributions of covariates to femoral neck (hip), one-third distal radius (wrist), and lumbar spine BMD.

RESULTS

Factors positively associated with BMD in multivariate models at the three sites were black race and appendicular lean mass. Asthma was consistently negatively associated. Various other risk factors also contributed significantly to each of the individual sites. R (2) values for the hip, wrist, and spine were 41%, 30%, and 24%, respectively. Lean mass accounted for the most explained variance at all three sites.

CONCLUSIONS

These data emphasize the limitation of focusing on individual risk factors and highlight the importance of potentially modifiable lean mass in predicting BMD.

Natural history and correlates of hip BMD loss with aging in men of African ancestry: the Tobago Bone Health Study

Little is known about the magnitude, pattern, and determinants of bone loss with advancing age among men, particularly among those of African descent. We examined the rate of decline in hip BMD and identified factors associated with BMD loss among 1478 Afro-Caribbean men >or=40 yr of age. BMD was measured at baseline and after an average of 4.4 yr by DXA. The rate of decline in femoral neck BMD was 0.29 +/- 0.81%/yr in the total sample (p < 0.0001). However, a U-shaped relationship between advancing age and the rate of decline in BMD was observed. The rate of decline in BMD at the femoral neck was -0.38 +/- 0.77%/yr among men 40-44 yr of age, decelerated to -0.15 +/- 0.81%/yr among men 50-54 yr of age, and then accelerated to -0.52 +/- 0.90%/yr among those 75+ yr of age (all p < 0.003). Men who lost >or=5% of their body weight during follow-up had significantly greater BMD loss than those who remained weight stable or gained weight (p < 0.0001). The relationship between weight loss and BMD loss was more pronounced among men who were older and leaner at study entry (p < 0.03). We also observed a strong impact of advanced prostate cancer and its treatment with androgen deprivation on BMD loss. Men of African ancestry experience substantial BMD loss with advancing age that seems to be comparable to the rate of loss among white men in other studies. Additional studies are needed to better define the natural history and factors underlying bone loss with aging in men of African ancestry.

Serum 25-hydroxyvitamin D and bone mineral density among Hispanic men

There are few data on the skeletal health of Hispanic men. We observed differences in vitamin D deficiency and low BMD between Hispanic ethnic subgroups that persisted with adjustment for risk factors. Our data indicate a substantial burden of low BMD and vitamin D deficiency among Hispanic men.

INTRODUCTION

Disparities within ethnic groups are generally ignored, but in evolving populations they may have implications for public health. We examined ethnic variation in serum 25-hydroxyvitamin D [25(OH)D] and bone mineral density (BMD) among Hispanic American men.

METHODS

Three hundred and fifty-eight Hispanic males 30 to 79 years of age were studied. Logistic regression models assessed variation in odds of vitamin D deficiency (<20 ng/mL) and low BMD (T-score<-1) by ethnicity, with and without adjustment for risk factors (age, smoking, occupation, physical activity, body mass index, and sunlight exposure).

RESULTS

Vitamin D deficiency was most common among Puerto Rican (26%), compared with Dominican (21%), Central American (11%), and South American (9%) men. Percentages with low BMD were: South American (44%), Puerto Rican (34%), Dominican (29%), and Central American (23%). Adjustment for age and risk factors failed to account for Hispanic subgroup differences in vitamin D deficiency and low BMD. Population estimates indicate a substantial burden of low BMD and vitamin D deficiency among Hispanic men.

CONCLUSIONS

Our findings underscore the importance of examining the skeletal health of Hispanic subgroups, and suggest that a considerable number of Hispanic men may be at elevated risk of fracture and vitamin D deficiency.

Correlations between serum testosterone, estradiol, and sex hormone-binding globulin and bone mineral density in a diverse sample of men

CONTEXT

The relationship between hormones and bone mineral density (BMD) in men has received considerable attention. However, most studies have been conducted in homogenous populations, and it is not known whether differences in hormones impact racial and ethnic differences in BMD.

OBJECTIVE

Our objective was to examine associations of testosterone, estradiol, and sex hormone-binding globulin (SHBG) with BMD in a racially and ethnically diverse population.

DESIGN

This was a population-based, observational survey.

PARTICIPANTS

A total of 976 Black, Hispanic, and white randomly selected men ages 30-79 yr from the Boston Area Community Health/Bone Survey were included.

OUTCOME

BMD at the hip, wrist, and spine were calculated.

RESULTS

The mean age of the sample was 46.7 +/- 12.4 yr. BMD levels were highest in black men, followed by Hispanic and then white men. Associations between hormones and BMD were consistent across racial and ethnic groups. Total and free testosterone was not correlated with BMD in age- or multivariate-adjusted models. SHBG was inversely correlated with total hip and ultradistal radius BMD after age adjustment, but not with multivariate adjustment for age, lean mass, fat mass, physical activity, self-rated health, and smoking. Total and free estradiol levels were positively and significantly correlated with femoral neck and total hip BMD, even with multivariate adjustment (partial correlations ranged between 0.11 and 0.16). However, estradiol levels failed to account for racial and ethnic differences in hip BMD.

CONCLUSIONS

In our diverse population, neither serum total nor free testosterone levels were associated with BMD. Correlations between BMD and estradiol were significant but did not appear to account for any of the observed racial and ethnic differences in BMD. These findings suggest that differences in hormone levels are not a major contributor to the observed differences in BMD between Black, Hispanic, and white men.

Age trends in proximal femur geometry in men: variation by race and ethnicity

Data on bone architecture in diverse male populations are limited. We examined proximal femur geometry in 1,190 black, Hispanic, and white men. Cross-sectional analyses indicate greatest bone strength among black men, and greater age-related differences in bone strength among Hispanic men than other subjects at the narrow neck and intertrochanter regions of the proximal femur.

INTRODUCTION

Although race/ethnic differences in bone mass are well-documented, less is known about differences in bone architecture. We examined proximal femur geometry in a diverse, randomly-sampled population of 1,190 community-dwelling men (age 30-79 y).

METHODS

Dual X-ray absorptiometry scans were obtained for 355 black, 394 Hispanic, and 441 white subjects. Measures were obtained for the narrow neck (NN), intertrochanter (IT) and shaft regions of the proximal femur via hip structural analysis. Analyses considered bone mineral density (BMD, g/cm2), outer diameter (cm), cross-sectional area (CSA, cm2), section modulus (Z, cm3), and buckling ratio (BR). Results were adjusted for height, weight and physical activity level.

RESULTS

Black subjects exhibited greater age-specific BMD, CSA and Z, than their white counterparts. For instance, at age 50 y, NN BMD was approximately 11% higher among black men (p < 0.001). Hispanic men exhibited sharper age-related differences in NN and IT BMD than did others. IT BMD, for instance, decreased by 2.4% with 10 y age among Hispanic subjects, but had virtually no age trend in others (p < 0.001).

CONCLUSIONS

These results imply greater bone strength among black American men than among their white counterparts, and may indicate elevated fracture risk among older Hispanic American subpopulations.

The relationship between body composition and bone mineral content: threshold effects in a racially and ethnically diverse group of men

We examined BMC and body composition in 1,209 black, Hispanic, and white men. Weight, BMI, waist circumference, and fat mass were associated with BMC only up to certain thresholds, whereas lean mass exhibited more consistent associations. The protective influence of increased weight appears to be driven by lean mass.

INTRODUCTION

Reduced body size is associated with decreased bone mass and increased fracture risk, but associations in men and racially/ethnically diverse populations remain understudied. We examined bone mineral content (BMC) at the hip, spine, and forearm as a function of body weight, body mass index (BMI), waist circumference, fat mass (FM), and nonbone lean mass (LM).

METHODS

The design was cross-sectional; 363 non-Hispanic black, 397 Hispanic, and 449 non-Hispanic white residents of greater Boston participated (N = 1,209, ages 30-79 y). BMC, LM, and FM were measured by DXA. Multiple linear regression was used to describe associations.

RESULTS

Weight, BMI, waist circumference, and FM were associated with BMC only up to certain thresholds. LM, by contrast, displayed strong and consistent associations; in multivariate models, femoral neck BMC exhibited a 13% increase per 10 kg cross-sectional increase in LM. In models controlling for LM, positive associations between BMC and other body composition measures were eliminated. Results did not vary by race/ethnicity.

CONCLUSIONS

The protective effect of increased body size in maintaining bone mass is likely due to the influence of lean tissue. These results suggest that maintenance of lean mass is the most promising strategy in maintaining bone health with advancing age.

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

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

INTRODUCTION

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

MATERIALS AND METHODS

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

RESULTS

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

CONCLUSIONS

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

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

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

Racial and ethnic differences in bone turnover markers in men

CONTEXT

Whereas racial and ethnic differences in fracture risk and bone mineral density (BMD) in men have been well described, the influence of race and ethnicity on biochemical markers of bone turnover is less clear.

METHODS

To examine the relationship between bone turnover, BMD, and race and ethnicity in men, we measured BMD, serum intact osteocalcin (OC), and serum C-terminal telopeptides of type 1 collagen (CTx) in 1029 men (aged 30-79 yr) enrolled in the Boston Area Community Health/Bone Survey, a population-based random sample of Black, Hispanic, and White. Men with diseases or on medications known to affect bone metabolism were excluded from the analysis. Mean serum levels of OC and CTx were adjusted for age, month and time of blood sample, and 25-hydroxyvitamin D.

RESULTS

Compared with Black men, adjusted mean OC levels were 17.6 and 20.5% higher in Hispanic (P = 0.02) and White men (P < 0.01), respectively. There was no significant difference between White and Hispanic men. Adjusted mean CTx levels were 14.3% higher in White men, compared with Black men (P = 0.04), but no other differences were significant. OC declined by 0.4%/yr from age 30 to 65 yr and increased thereafter by 2.1%/yr. The age trend in CTx appeared to follow a pattern consistent with a quadratic function of age. Model-estimated annual percent changes within age decade were as follows: 30-39 yr, -2.5%; 40-49 yr, -1.4%; 50-59 yr, -0.3%; 60-69 yr, +0.9%; 70-79 yr, +1.7%. There was no variation in the shape of the age trend in OC or CTx by race or ethnic group. Correlations between bone turnover markers and BMD (adjusted for age, height, weight, serum 25-hydroxyvitamin D, and PTH and month and time of blood sample) were generally weak.

CONCLUSIONS

Bone turnover markers are lower in Black men, compared with White and Hispanic men. Age trends in bone turnover markers are not influenced by race or ethnicity. Future studies in this cohort and others are needed to explore further these reported differences in bone metabolism among Black, Hispanic, and White men.

Race/ethnic differences in bone mineral density in men

The epidemiology of osteoporosis in male and minority populations is understudied. We compared BMD in 1,209 Black, Hispanic, and White men. Black men exhibited higher BMD than Hispanic or White men. Age-related BMD decreases were greatest among Hispanic men. Results may help explain variation in hip fracture rates by race/ethnicity.

INTRODUCTION

The epidemiology of osteoporosis in male and minority populations is understudied. To address this concern, we conducted a study of skeletal health in a diverse population of adult males.

METHODS

A total of 367 Black, 401 Hispanic, and 451 White men aged 30-79 years were randomly sampled from Boston, MA. Bone densitometry (bone area (BA), bone mineral content (BMC), and bone mineral density (BMD)) at the whole body, hip, lumbar spine, and forearm was performed. Multiple regression analyses on 1,209 men with available data were used to describe race/ethnic group-specific means (height- and age-adjusted) and age trends (height-adjusted) in BMC, BA, and BMD. Results were weighted to represent the Boston male population aged 30-79 years.

RESULTS

Black men had greater BMC and BMD than Hispanic or White men. Femoral neck BMD was 5.6% and 13.3% higher in Black men than in Hispanic and White men, respectively. Differences between Hispanic and White subjects were restricted to the hip. Age-related declines in BMC and BMD were significantly steeper among Hispanic than Black or White men.

CONCLUSIONS

Differences in BMC and BMD could explain variation in fracture rates among Black, Hispanic, and White men. The steeper age-related BMD decline in Hispanic men is of particular concern.

Genetic and environmental determinants of volumetric and areal BMD in multi-generational families of African ancestry: the Tobago Family Health Study

BMD is higher and fracture risk is lower among individuals of African versus European descent, but little is known about the genetic architecture of BMD in the former group. Heritabilities of areal and volumetric BMD were moderate in our large families of African descent but differed for trabecular and cortical BMD.

INTRODUCTION

Populations of African ancestry have lower osteoporotic fracture risk and higher BMD than other ethnic groups. However, there is a paucity of information regarding the genetic and environmental influences on bone health among populations of African heritage.

MATERIALS AND METHODS

We dissected the genetic architecture of areal BMD measured by DXA at the proximal femur, lumbar spine, and whole body and volumetric BMD measured by pQCT at the distal and proximal radius and tibia in 283 women and 188 men > or =18 years of age (mean, 43 years) from eight multigenerational Afro-Caribbean families (mean family size > 50). Using quantitative genetic methods, we estimated the residual heritability and the effects of anthropometric, demographic, lifestyle, and medical variables on areal and volumetric BMD.

RESULTS

Compared with U.S. non-Hispanic blacks and whites, areal BMD at the femoral neck was highest in the Afro-Caribbean men and women at all ages. Trabecular volumetric BMD decreased linearly with increasing age, whereas cortical volumetric BMD did not decrease until age 40-49, especially in women. Anthropometric, lifestyle, and medical factors accounted for 12-32% of the variation in areal and volumetric BMD, and residual heritabilities (range, 0.23-0.52) were similar to those reported in other ethnic groups. Heritability of cortical BMD was substantially lower than that of areal or trabecular volumetric BMD, although the measured covariates accounted for a similar proportion of the total phenotypic variation.

CONCLUSIONS

Our study is the first comprehensive genetic epidemiologic analysis of volumetric BMD measured by QCT and the first analysis of these traits in extended families of African descent. Genes account for as much or more of the total variation in areal and volumetric BMD than do environmental factors, but these effects seem to differ for trabecular and cortical bone.

Osteoporosis in hemodialysis patients revisited by bone histomorphometry: a new insight into an old problem

Osteoporosis in hemodialysis patients is associated with high morbidity and mortality and, although extensively studied by noninvasive methods, has never been assessed through bone biopsy. The aim of this study was to use histomorphometry to evaluate osteoporosis and identify factors related to its development in hemodialysis patients. We conducted a cross-sectional study involving 98 patients (35 women and 63 men; mean age: 48.4 +/- 13 years) on hemodialysis for 36.9 +/- 24.7 months. Patients were submitted to transiliac bone biopsy with double tetracycline labeling. The bone metabolism factors ionized calcium, phosphorus, bone alkaline phosphatase, deoxypyridinoline, intact parathyroid hormone, and 25(OH) vitamin D were evaluated, as were the bone remodeling cytokines osteoprotegerin (OPG), soluble receptor-activator of NF-kappabeta ligand (sRANKL) and tumor necrosis factor-alpha (TNF)alpha. Osteoporosis was defined as trabecular bone volume (BV/TV) greater than 1 s.d. below normal (men <17.4%; women <14.7%). Forty-five patients (46%) presented osteoporosis, which was correlated with white race. We found BV/TV to correlate with age, OPG/sRANKL ratio, TNFalpha levels, and length of amenorrhea. In multiple regression analysis adjusted for sex and age, length of amenorrhea, white race, and OPG/sRANKL ratio were independent determinants of BV/TV. Histomorphometric analysis demonstrated that osteoporotic patients presented normal eroded surface and low bone formation rate (BFR/BS). Osteoporosis is prevalent in hemodialysis patients. Low BFR/BS could be involved in its development, even when bone resorption is normal. Cytokines may also play a role as may traditional risk factors such as advanced age, hypogonadism, and white race.

Determinants of bone mass and bone size in a large cohort of physically active young adult men

The determinants of bone mineral density (BMD) at multiple sites were examined in a fit college population. Subjects were 755 males (mean age = 18.7 years) entering the United States Military Academy. A questionnaire assessed exercise frequency and milk, caffeine, and alcohol consumption and tobacco use. Academy staff measured height, weight, and fitness. Calcaneal BMD was measured by peripheral dual-energy x-ray absorptiometry (pDXA). Peripheral-quantitative computed tomography (pQCT) was used to measure tibial mineral content, circumference and cortical thickness. Spine and hip BMD were measured by DXA in a subset (n = 159). Mean BMD at all sites was approximately one standard deviation above young normal (p < 0.05). African Americans had significantly higher hip, spine and heel BMD and greater tibial mineral content and cortical thickness than Caucasians and Asians. In Caucasians (n = 653), weight was a significant determinant of BMD at every skeletal site. Prior exercise levels and milk intake positively related to bone density and size, while caffeine had a negative impact. There was an apparent interaction between milk and exercise in BMD at the heel, spine, hip and tibial mineral content and cortical thickness. Our data confirm the importance of race, body size, milk intake and duration of weekly exercise as determinants of BMD and bone size.

Characteristics of elderly patients admitted to an urban tertiary care hospital with osteoporotic fractures: correlations with risk factors, fracture type, gender and ethnicity

Osteoporosis is a major public health problem in the United States of America and around the world, largely due to the morbidity and mortality associated with osteoporotic fractures. In the past decade, large epidemiologic studies have contributed greatly to our understanding of patients who fracture. However, most studies are limited to postmenopausal white women. In this retrospective review, we analyze data from 185 men and women with acute fragility fractures who received osteoporosis consultations during admission to a single urban hospital between 2001 and 2003. Men and women differed in terms of risk factors for falls and osteoporosis but had areal bone mineral density (BMD) measurements remarkably similar, except at the total hip. Black and Hispanic subjects with fractures were significantly younger than whites yet were much more likely to have serious co-morbidities, such as diabetes mellitus and hypertension. In spite of significantly higher BMD measurements, black patients had the highest rates of vitamin D deficiency and secondary hyperparathyroidism. Patients admitted with hip fractures differed from those with non-hip fractures on a number of important variables. Based on these data, we conclude that elderly subjects admitted to an urban hospital with osteoporotic fractures are a heterogeneous group, with features that vary according to fracture type, gender and ethnicity. Future studies of patients with clinical fragility fractures should include ample numbers of men and ethnic minorities, since differences in underlying risk factors may suggest alternative strategies for fracture prevention.

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.

Racial differences in rate of decline in bone mass in older men: the Baltimore men's osteoporosis study

Older black men have higher adjusted BMD than older white men. Using data from a longitudinal cohort study of older men followed for a mean of 18.8 +/- 6.5 (SD) months, we found that older black men have a higher rate of decline in femoral neck and total hip BMD and femoral neck BMAD than older white men.

INTRODUCTION

Older black men have higher adjusted BMD compared with older white men. The difference in BMD may be caused by having attained higher peak bone mass as young adults and/or having a slower rate of decline in bone mass as adults. There are few published longitudinal data on change in bone mass in older white men and no published data for older black men.

MATERIALS AND METHODS

Three hundred forty-nine white men and 119 black men 65 of age (mean age, 75 +/- 5.7 and 72 +/- 5.6 years, respectively) who participated in the longitudinal component of the Baltimore Men's Osteoporosis Study returned for a second visit after a mean of 18.8 +/- 6.5 (SD) months and were not taking medications used to treat low bone mass at either visit. BMD was measured at the femoral neck and total hip by Hologic-certified technicians using a QDR 2000 at the baseline visit (V1) and QDR 4500 at the first follow-up visit (V2). Participants also completed self-administered and interviewer-administered questionnaires and underwent standardized clinic examinations. Bone mineral apparent density (BMAD) at the femoral neck was calculated as an estimate of volumetric BMD. Annual crude and multiple variable adjusted percent changes in BMD and BMAD were calculated.

RESULTS

In univariate analyses, black men had lower percent decline in femoral neck and total hip BMD and femoral neck BMAD than white men. In addition, older age at baseline, lower baseline weight, current smoking, and lower baseline BMD were associated with greater percent decline per year in femoral neck BMD; older age at baseline, current smoking, and lower baseline BMD were associated with greater percent decline per year in total hip BMD; and older age at baseline and lower baseline femoral neck BMAD were associated with greater percent decline per year in femoral neck BMAD. Racial differences in bone loss persisted in multiple variable models that controlled for other factors associated with change in BMD and BMAD.

CONCLUSIONS

Older black men seem to lose bone mass at a slower rate than older white men. These differences in the rate of bone loss may account, in part, for the racial disparities in BMD and BMAD and risk of osteoporotic fractures among older men.

Ethnic differences in bone mineral density between inuit and Caucasians in north Greenland are caused by differences in body size

Data on bone mineral density (BMD) in living Inuit are limited and BMD measurements in Arctic Inuit using Dualenergy X-ray Absorptiometry (DXA) are lacking. Ethnicity may be important for bone mass. The aim of this study was to validate DXA in rural Arctic Greenland, to measure BMD in Greenland Inuit and Caucasians, and to estimate the importance of ethnicity for BMD. We measured the BMD in 80 healthy subjects living in Ilulissat and Saqqaq in North Greenland twice in both distal forearms and in both heels using peripheral DXA (pDXA). Participants were stratified by origin (Inuit[settlement])/Caucasians, n = 33 [19]/28), gender (men/women, n = 37/43), and age (30-39/40-49, n = 32/48). Caucasians were bigger than Inuit (men/women, height p < 0.001/p < 0.001; weight p = 0.01/ p = 0.026), but had similar BMI (p = 0.42/0.70). Triplicate pDXA measurements showed individual CV% = 0.16-1.79%; overall CV% = 1.1% (forearm)/1.0% (heel). Data followed the normal distribution (p = 0.65-0.99) with identical variances between Inuit and Caucasians (p = 0.12-0.63). Mean BMD in right forearm/left forearm/right heel/left heel was: Inuit men 0.570/0.568/0.549/0.536 g/cm2; Inuit women 0.484/0.474/0.473/0.464 g/cm2; Caucasian men 0.580/0.570/0.646/0.638 g/cm2; Caucasian women 0.495/0.496/0.552/0.553 g/cm2. An ethnic difference in heel BMD (p < 0.001) disappeared when adjusted for weight (p = 0.30). No difference was found in forearm BMD. In conclusion, pDXA is feasible and reliable in rural Greenland. Ethnic differences in BMD are small and may reflect differences in body size.