Racial and ethnic differences in bone turnover markers in men

Bone Turnover Markers: Basic Biology to Clinical Applications

Bone turnover markers (BTMs) are used widely, in both research and clinical practice. In the last 20 years, much experience has been gained in measurement and interpretation of these markers, which include commonly used bone formation markers bone alkaline phosphatase, osteocalcin, and procollagen I N-propeptide; and commonly used resorption markers serum C-telopeptides of type I collagen, urinary N-telopeptides of type I collagen and tartrate resistant acid phosphatase type 5b. BTMs are usually measured by enzyme-linked immunosorbent assay or automated immunoassay. Sources contributing to BTM variability include uncontrollable components (e.g., age, gender, ethnicity) and controllable components, particularly relating to collection conditions (e.g., fasting/feeding state, and timing relative to circadian rhythms, menstrual cycling, and exercise). Pregnancy, season, drugs, and recent fracture(s) can also affect BTMs. BTMs correlate with other methods of assessing bone turnover, such as bone biopsies and radiotracer kinetics; and can usefully contribute to diagnosis and management of several diseases such as osteoporosis, osteomalacia, Paget's disease, fibrous dysplasia, hypophosphatasia, primary hyperparathyroidism, and chronic kidney disease-mineral bone disorder.

Associations of Osteocalcin Forms With Metabolic Syndrome and Its Individual Components in Older Men: The Health In Men Study

CONTEXT

The osteoblast-derived polypeptide, osteocalcin (OC), has been associated with lower risk of type 2 diabetes and metabolic syndrome (MetS) in several epidemiological studies. Animal studies have indicated the undercarboxylated form of OC (ucOC) drives its association with metabolic outcomes.

OBJECTIVE

We compared associations of ucOC and carboxylated OC (cOC) with MetS and its components in older men.

METHODS

A cross-sectional analysis of 2575 men aged ≥70 years and older resident in Perth, Western Australia. ucOC was assayed using a hydroxyapatite-binding method, and cOC calculated by subtracting ucOC from total OC. Main outcome measures were MetS and its components.

RESULTS

Both lower serum ucOC and cOC levels, and the proportion of cOC (%cOC) were associated with less favorable metabolic parameters (higher waist circumference, triglyceride, glucose, blood pressure, and lower high-density lipoprotein cholesterol), whereas inverse associations were found with %ucOC. Men in the lowest quintile of ucOC had higher risk of MetS compared to men in the highest quintile (Q1 ≤ 7.7 vs Q5 > 13.8 ng/mL; OR = 2.4; 95% CI, 1.8-3.2). Men in the lowest quintile of cOC had higher risk of MetS compared to those in the highest quintile (≤ 5.8 vs > 13.0 ng/mL; OR = 2.4; 95% CI, 1.8-3.2).

CONCLUSION

Lower concentrations of serum ucOC or cOC were associated with less favorable metabolic parameters and a higher risk of MetS. In contrast, a lower proportion of ucOC was associated with better metabolic parameters and lower MetS risk. Further research is warranted to determine whether ucOC and cOC are suitable biomarkers for cardiometabolic risk in men.

Bone Loss and Radiographic Damage Profile in Rheumatoid Arthritis Moroccan Patients

Background

Rheumatoid arthritis (RA) is a known cause of joint destruction and systemic bone loss. In this study, we aimed to evaluate the bone damage and bone loss profiles of established RA patients.

Methods

We designed a cross-sectional study on a cohort of established RA patients. The bone evaluation was performed by obtaining standard X-ray images of hands and feet combined with bone mineral density (BMD) measurements. Radiographic joint damage was calculated by the modified total Sharp /van der Heijde score (mTSS). BMD was obtained by performing dual energy X-ray absorptiometry of the lumbar spine and femoral neck. Data on age, smoking, alcoholism, steroid prescription, body mass index (BMI), disease duration, disease activity, and functional disability were collected.

Results

A total of 93 RA patients were recruited. Their mean age was 51.59±12.38 years, with a mean disease duration of 12.07±9.19 years. A total of 36.6% of patients had osteoporosis, and the mean mTSS was 70.33±48.93. Both hip (P=0.0005) and lumbar BMD (P=0.0005) were correlated with mTSS. Backward regression analyses determined that bone damage was associated with high titers of rheumatoid factor, low lumbar BMD, and low BMI. General bone loss was associated with gender, steroid dose, steroid duration, menopause, and BMI.

Conclusions

Bone damage was associated with low BMI and axial bone loss in our RA population.

Increase in bone turnover markers in HIV patients treated with tenofovir disoproxil fumarate combined with raltegravir or efavirenz

Introduction

Accelerated bone loss and osteoporosis are multifactorial comorbidities related to HIV and its treatments; however, their mechanisms remain elusive. Identifying HIV treatments that are differentially linked to osteoporosis risk, and clinical factors associated with HIV-related osteoporosis may enable optimizing anti-retroviral treatment (ART) and anti-osteoporosis therapy in preventing or treating this debilitating complication. This study aims to evaluate the dynamics of bone turnover markers after initiation of two commonly used antiretroviral regimens.

Methods

A prospective matched cohort study. Thirty treatment-naïve male patients (mean age 40 ± 10y) who initiated treatment with truvada (tenofovir disoproxil fumarate (TDF)/emtricitabine (FTC)) + raltegravir or TDF/FTC + efavirenz were included in the study. Control group included 15 treatment-naive HIV patients. Serum morning fasting level of P1NP and CTX were measured 0, 1, 6, and 12 months after treatment initiation in the two study groups, and at 0, 6 and 12 months in the control group.

Results

In both treatment groups, but not in the control group, both markers increased significantly over time with no difference in BTM between patients treated with raltegravir or efavirenz. Levels of P1NP were statistically higher at 6 and 12 months after treatment initiation in both treatment groups compared to the controls, while CTX during treatment increased in both treatment groups but was significantly higher only in the raltegravir treatment group after 12 months. The ratio of area under the curve of P1NP/CTX correlated with CD4 increment.

Conclusions

Treatment initiation with raltegravir or efavirenz combined with TDF/FTC is associated with increased bone turnover. Thus, therapy that optimize bone turnover is needed to reduce bone loss at this vulnerable period and improve long-term bone health.

Predicting bone turnover following tobacco exposure using bone alkaline phosphatase and N-telopeptide biomarkers and possible variability and effect modification of these markers by race/ethnicity

Introduction: This study investigated the systemic response of serum bone alkaline phosphatase (SBAP) and urinary N-telopeptide (UNTX) to tobacco exposure and environmental tobacco smoke (ETS) and the possible effect modification (and variability) of this response by racial/ethnic origin.Methods: Data (n = 5411) were obtained from the National Health and Nutrition Examination Survey, with data analysis done on adults aged ≥ 20 years. Outcome variables were SBAP and UNTX. Independent variable was tobacco exposure measured using serum cotinine levels and adjusted for covariates. Generalized linear models were used to explore associations.Results: A percentage increase in log transformed serum cotinine was associated with a 0.005 percentage increase in log transformed SBAP (CI: 0.002, 0.008) and 0.02 percentage increase in log transformed UNTX (CI: -0.01, 0.04) with interaction between cotinine and race/ethnicity (p = 0.01). Stratifying by race/ethnicity, tobacco exposure was associated with significant decreases in UNTX among non-Hispanic Whites - 0.008(-0.014, -0.002) and Mexican Americans -0.014 (-0.025, -0.002) only. Categories of serum cotinine were associated with a monotonic increase in SBAP (p for trend <0.001) and monotonic non-linear decrease in UNTX (p for trend > 0.05).Conclusions: Tobacco and environmental tobacco exposure are associated with SBAP and increased bone formation. The response of UNTX to these exposures is modified by race/ethnicity with non-Hispanic Whites and Mexican-Americans less sensitive to the resorptive effects of tobacco exposure on bone.

Cholecalciferol Supplementation Promotes Bone Turnover in Chinese Adults with Vitamin D Deficiency

BACKGROUND

Bone turnover markers (BTMs) are proposed as alternative indicators for bone mineral density in diagnosis and management of osteoporosis. However, little is known about the effects of vitamin D supplementation on BTMs in nonwhite populations.

OBJECTIVE

We aimed to investigate the responses in BTMs after vitamin D supplementation in Asians.

METHODS

In this secondary data analysis of a randomized, double-blind, placebo-controlled trial, 448 Chinese adults [mean ± SD age: 31.9 ± 8.0 y; mean ± SD body mass index (kg/m2): 22.1 ± 2.6; 69% were women] with vitamin D deficiency (serum 25-hydroxyvitamin D [25(OH)D] <50 nmol/L) received 2000 IU/d cholecalciferol or placebo for 20 wk. Serum concentrations of 25(OH)D, parathyroid hormone (PTH), calcium, and markers of bone formation and resorption were measured at weeks 0 and 20. Intention-to-treat analysis was applied, and between-group differences were compared by general linear models with adjustments.

RESULTS

Cholecalciferol supplementation increased the serum bone alkaline phosphatase (BALP) concentration (+1.7 ± 1.9 µg/L) significantly more than placebo (+1.1 ± 1.7 µg/L; P = 0.004), but not circulating concentrations of procollagen type I N-terminal propeptide (PINP), β-isomerized C-terminal telopeptide of type I collagen (β-CTX), or tartrate-resistant acid phosphatase 5b (TRAP5b) (P ≥ 0.53). Notably, a pooled analysis indicated that changes in serum 25(OH)D were positively associated with changes in serum BALP, PINP, and TRAP5b (r = 0.07-0.16, P ≤ 0.02), but inversely with changes in PTH (r = -0.15, P < 0.001). Among cholecalciferol-treated participants, individuals who achieved serum 25(OH)D ≥75 nmol/L had greater increases in serum β-CTX (224% compared with 146%; P = 0.02) and TRAP5b (22.2% compared with 9.1%; P = 0.007), but smaller decreases in serum calcium (-1.3% compared with -1.9%; P = 0.005) and calcium-phosphorus product (-2.6% compared with -3.3%; P = 0.02) compared with those with serum 25(OH)D <75 nmol/L.

CONCLUSIONS

Daily supplementation with 2000 IU cholecalciferol for 20 wk may promote bone formation in Chinese adults with vitamin D deficiency. More studies are needed to elucidate the potential clinical implications of BTMs.This trial was registered at clinicaltrials.gov as NCT01998763.

Low bone turnover in premenopausal women with type 2 diabetes mellitus as an early process of diabetes-associated bone alterations: a cross-sectional study

BACKGROUND

Individuals with Diabetes Mellitus (DM) are at increased risk for fracture due to the decrease in bone strength and quality. Serum procollagen type I intact N-terminal (P1NP) and serum C-terminal cross-linking telopeptide of type I collagen (CTX) as markers of bone formation and resorption, respectively, have been reported to be decreased in T2DM. It remains unclear whether diabetes-associated alterations in the bone turnover of T2DM individuals are related to the longer duration of the disease or may occur earlier. Furthermore, previous studies on BTMs in T2DM individuals have mostly been done in postmenopausal women with T2DM, which might have masked the DM-induced alterations of bone turnover with concurrent estrogen deficiency. This study aims to assess the levels of serum P1NP and CTX as markers of bone turnover in premenopausal women with and without T2DM.

METHODS

This cross-sectional study involves 41 premenopausal women with T2DM, and 40 premenopausal women without DM. Sampling was done consecutively. P1NP and CTX measurement was done using the electrochemi-luminescence immunoassay (ECLIA) method. Other data collected include levels of HbA1C, ALT, creatinine, eGFR and lipid profile.

RESULTS

Median (interquartile range) P1NP in T2DM is 29.9 ng/ml (24.7-41.8 ng/ml), while in non-DM is 37.3 ng/ml, (30.8-47.3 ng/ml; p = 0.007). Median (interquartile range) CTX in T2DM is 0.161 ng/ml (0.106-0.227 ng/ml), while in non-DM is 0.202 ng/ml (0.166-0.271 ng/ml; p = 0.0035). Levels of P1NP and CTX in the T2DM group did not correlate with the duration of disease, age, BMI or the levels of HbA1C.

CONCLUSIONS

Premenopausal women with T2DM indeed have lower bone turnover when compared with non-DM controls. This significantly lower bone turnover process starts relatively early in the premenopausal age, independent of the duration of DM. Gaining understanding of the early pathophysiology of altered bone turnover may be key in developing preventive strategies for diabetoporosis.

Bone mass, microarchitecture and strength are influenced by race/ethnicity in young adult men and women

Lower rates of fracture in both Blacks compared to Whites, and men compared to women are not completely explained by differences in bone mineral density (BMD). Prior evidence suggests that more favorable cortical bone microarchitecture may contribute to reduced fracture rates in older Black compared to White women, however it is not known whether these differences are established in young adulthood or develop during aging. Moreover, prior studies using high-resolution pQCT (HR-pQCT) have reported outcomes from a fixed-scan location, which may confound sex- and race/ethnicity-related differences in bone structure.

PURPOSE

We determined differences in bone mass, microarchitecture and strength between young adult Black and White men and women.

METHODS

We enrolled 185 young adult (24.2±3.4yrs) women (n=51 Black, n=50 White) and men (n=34 Black, n=50 White) in this cross-sectional study. We used dual-energy X-ray absorptiometry (DXA) to determine areal BMD (aBMD) at the femoral neck (FN), total hip (TH) and lumbar spine (LS), as well as HR-pQCT to assess bone microarchitecture and failure load by micro-finite element analysis (μFEA) at the distal tibia (4% of tibial length). We used two-way ANOVA to compare bone outcomes, adjusted for age, height, weight and physical activity.

RESULTS

The effect of race/ethnicity on bone outcomes did not differ by sex, and the effect of sex on bone outcomes did not differ by race/ethnicty. After adjusting for covariates, Blacks had significantly greater FN, TH and LS aBMD compared to Whites (p<0.05 for all). Blacks also had greater cortical area, vBMD, and thickness, and lower cortical porosity, with greater trabecular thickness and total vBMD compared to Whites. μFEA-estimated FL was significantly higher among Blacks compared to Whites. Men had significantly greater total vBMD, trabecular thickness and cortical area and thickness, but greater cortical porosity than women, the net effects being a higher failure load in men than women.

CONCLUSION

These findings demonstrate that more favorable bone microarchitecture in Blacks compared to Whites and in men compared to women is established by young adulthood. Advantageous bone strength among Blacks and men likely contributes to their lower risk of fractures throughout life compared to their White and women counterparts.

Risk of Stress Fracture Varies by Race/Ethnic Origin in a Cohort Study of 1.3 Million US Army Soldiers

Stress fractures (SF) are common and costly injuries in military personnel. Risk for SF has been shown to vary with race/ethnicity. Previous studies report increased SF risk in white and Hispanic Soldiers compared with black Soldiers. However, these studies did not account for the large ethnic diversity in the US military. We aimed to identify differences in SF risk among racial/ethnic groups within the US Army. A retrospective cohort study was conducted using data from the Total Army Injury and Health Outcomes Database from 2001 until 2011. SF diagnoses were identified from ICD-9 codes. We used Cox-proportional hazard models to calculate time to SF by racial/ethnic group after adjusting for age, education, and body mass index. We performed a sex-stratified analysis to determine whether the ethnic variation in SF risk depends on sex. We identified 21,549 SF cases in 1,299,332 Soldiers (more than 5,228,525 person-years of risk), revealing an overall incidence rate of 4.12 per 1000 person-years (7.47 and 2.05 per 1000 person-years in women and men, respectively). Using non-Hispanic blacks as the referent group, non-Hispanic white women had the highest risk of SF, with a 92% higher risk of SF than non-Hispanic black women (1.92 [1.81-2.03]), followed by American Indian/Native Alaskan women (1.72 [1.44-1.79]), Hispanic women (1.65 [1.53-1.79]), and Asian women (1.32 [1.16-1.49]). Similarly, non-Hispanic white men had the highest risk of SF, with a 59% higher risk of SF than non-Hispanic black men (1.59 [1.50-1.68]), followed by Hispanic men (1.19 [1.10-1.29]). When examining the total US Army population, we found substantial differences in the risk of stress fracture among racial/ethnic groups, with non-Hispanic white Soldiers at greatest risk and Hispanic, American Indian/Native Alaskan, and Asian Soldiers at an intermediate risk. Additional studies are needed to determine the factors underlying these race- and ethnic-related differences in stress fracture risk. © 2017 American Society for Bone and Mineral Research.

The Effects of Exercise on Cardiovascular Biomarkers: New Insights, Recent Data, and Applications

The benefit of regular exercise or physical activity with appropriate intensity on improving cardiopulmonary function and endurance has long been accepted with less controversy. The challenge remains, however, quantitatively evaluate the effect of exercise on cardiovascular health due in part to the amount and intensity of exercise varies widely plus lack of effective, robust and efficient biomarker evaluation systems. Better evaluating the overall function of biomarker and validate biomarkers utility in cardiovascular health should improve the evidence regarding the benefit or the effect of exercise or physical activity on cardiovascular health, in turn increasing the efficiency of the biomarker on individuals with mild to moderate cardiovascular risk. In this review, beyond traditional cytokines, chemokines and inflammatory factors, we systemic reviewed the latest novel biomarkers in metabolomics, genomics, proteomics, and molecular imaging mainly focus on heart health, as well as cardiovascular diseases such as atherosclerosis and ischemic heart disease. Furthermore, we highlight the state-of-the-art biomarker developing techniques and its application in the field of heart health. Finally, we discuss the clinical relevance of physical activity and exercise on key biomarkers in molecular basis and practical considerations.

Ethnic differences in heterotopic ossification following total hip arthroplasty

Aims

We aimed to assess the influence of ethnicity on the incidence of heterotopic ossification (HO) after total hip arthroplasty (THA).

Patients and Methods

We studied the six-month post-operative anteroposterior radiographs of 1449 consecutive primary THAs (1324 patients) and retrospectively graded them for the presence of HO, using the Brooker Classification.

Results

Based on multivariate analysis, African-American ethnicity was an independent risk factor for HO formation following THA with an adjusted odds ratio (OR) of 2.6 (95% confidence interval (CI) 1.3 to 5.2, p = 0.007) for severe HO and 1.9 (95% CI 1.3 to 2.7, p < 0.001) for any grade of HO.

Conclusion

Given the increased risk of HO formation, particularly high grade HO, and the potentially poorer outcomes associated with HO, it is important to consider using prophylaxis against HO in patients of African-American ethnicity undergoing THA. Take home message: African Americans are at an increased risk for developing heterotopic ossification and thus may benefit from HO prophylaxis. Cite this article: Bone Joint J 2016;98-B:761–6.

Bone Mineral Content as a Driver of Energy Expenditure in Prepubertal and Early Pubertal Boys

OBJECTIVE

To examine the associations of bone and bone-secreted factors with measures of energy metabolism in prepubertal and early pubertal boys.

STUDY DESIGN

Participants in this cross-sectional, observational study included 37 (69% black, 31% white) boys, aged 7-12 years (Tanner stage <III). Dual-energy X-ray absorptiometry was used to measure bone mineral content (BMC) and percent body fat. Indirect calorimetry was used to assess resting energy expenditure (REE). Fasting blood levels of osteocalcin (OCN), fibroblast growth factor 23 (FGF23), insulin, glucose, precursor product of type I collagen (N-terminal pro-peptide) and type I collagen, and C-terminal cross-linked telopeptide were measured. Pearson correlations were performed to evaluate relationships among BMC, OCN, FGF23, fasting insulin and glucose, and REE. Multiple linear regression models were used to test associations between OCN and BMC (independent variables) with fasting insulin and glucose and with REE, adjusting for bone turnover markers and further adjusted for percent body fat.

RESULTS

BMC was correlated with REE and insulin. OCN was correlated with glucose in blacks only (r = 0.45, P < .05). FGF23 was not correlated with any markers of energy metabolism. BMC was associated with insulin level in blacks (β = 0.95, P = .001), which was attenuated by percent body fat (β = 0.47, P = .081). BMC was associated with REE in whites (β = 0.496.7, P < .05) and blacks (β = 619.5, P < .0001); but accounting for percent body fat attenuated the association in whites (β = 413.2, P = .078).

CONCLUSION

Our findings suggest that BMC is a determinant of fasting insulin and REE, and that the contribution of body fat appears to be race-specific. Endocrine effects of FGF23 and OCN on energy metabolism were not apparent.

TRIAL REGISTRATION

Registered with ClinicalTrials.gov: NCT02040740, NCT02040727, and NCT01410643.

Ethnic differences in bone and mineral metabolism in healthy people and patients with CKD

Several studies have shown racial differences in the regulation of mineral metabolism, in the acquisition of bone mass and structure of individuals. In this review, we examine ethnic differences in bone and mineral metabolism in normal individuals and in patients with chronic kidney disease. Black individuals have lower urinary excretion and increased intestinal calcium absorption, reduced levels of 25(OH)D, and high levels of 1.25(OH)2D and parathyroid hormone (PTH). Body phosphorus concentration is higher and the levels of FGF-23 are lower than in whites. Mineral density and bone architecture are better in black individuals. These differences translate into advantages for blacks who have stronger bones, less risk of fractures, and less cardiovascular calcification. In the United States of America, the prevalence of kidney disease is similar in different ethnic groups. However, black individuals progress more quickly to advanced stages of kidney disease than whites. This faster progression does not translate into increased mortality, higher in whites, especially in the first year of dialysis. Some ethnicity-related variations in mineral metabolism persist when individuals develop CKD. Therefore, black patients have lower serum calcium concentrations, less hyperphosphatemia, low levels of 25(OH)D, higher levels of PTH, and low levels of FGF-23 compared with white patients. Bone biopsy studies show that blacks have greater bone volume. The rate of fractures and cardiovascular diseases are also less frequent. Further studies are required to better understand the cellular and molecular bases of these racial differences in bone mineral metabolism and thus better treat patients.

Population pharmacokinetic and pharmacodynamic modeling of different formulations of ONO-5334, cathepsin K inhibitor, in Caucasian and Japanese postmenopausal females

ONO-5334, a selective inhibitor of cathepsin K, is a potential new treatment for osteoporosis. The objectives of this study were to (1) develop population pharmacokinetic-pharmacodynamic (PK-PD) models for ONO-5334 using dose-ascending data from healthy postmenopausal females, (2) examine comparability of PK and/or PD profile between Caucasian and Japanese, and (3) compare PK-PD profile between immediate release tablet (IRT) and sustained release tablet (SRT). The population PK-PD models were developed for each formulation for post-dose levels of bone resorption markers (serum CTX and NTX). The data were provided from 4 phase 1 studies with total of 201 Caucasian and 94 Japanese subjects. Plasma concentrations of ONO-5334 and bone resorption markers were thoroughly evaluated in those studies. An indirect response model described relationships between bone resorption markers and plasma concentrations of ONO-5334. There was no significant difference in PK and pharmacodynamic potency (IC50 ) between Caucasian and Japanese. Based on the developed model, serum CTX and NTX after administration of ONO-5334 IRT or SRT were simulated, and the results showed that ONO-5334 SRT would provide comparable PD effect on bone resorption markers with lower dose relative to IRT.

Familial resemblance of bone turnover rate in men aged 40 and over-the MINOS study

Familial resemblance of bone mineral density (BMD) is well known in both sexes. Fewer data concern the familial resemblance of bone turnover markers (BTMs) and bone size in men. Our aim was to assess the correlation of BMD, bone size, BTM levels and hormones regulating bone turnover in 50 pairs of brothers aged ≥ 40 and 50 pairs of unrelated men matched for age, weight and height. BMD was measured at the lumbar spine, hip, forearm and whole body. We measured serum osteocalcin (OC), bone-specific alkaline phosphatase (bone ALP), N-terminal propeptide of type I procollagen (PINP) and C-terminal telopeptide of type I collagen (CTX-I) as well as urinary free and total deoxypyridinoline (DPD) and CTX-I. After adjustment for age, weight, bioavailable 17β-estradiol, and parathyroid hormone, all the BTMs (except bone ALP) were significantly correlated in the brothers (ICC = 0.36-0.64). Most of these correlations were significantly stronger than in the unrelated men. Bone size correlated significantly between the brothers (ICC = 0.55-0.65). These correlations were significantly stronger than in the unrelated men. BMD correlated between the brothers at most of the skeletal sites and, for some of them, more strongly than in the unrelated men. Serum levels of LDL-cholesterol and triglycerides were significantly correlated in the brothers, but not more strongly than in the unrelated men. BTM levels correlated independently in the brothers aged ≥ 40, when their shared environment was limited. These data suggest a substantial hereditary determinism of the BTM levels in men.

Cohort profile: the Boston Area Community Health (BACH) survey

The Boston Area Community Health (BACH) Survey is a community-based, random sample, epidemiologic cohort of n = 5502 Boston (MA) residents. The baseline BACH Survey (2002-05) was designed to explore the mechanisms conferring increased health risks on minority populations with a particular focus on urologic signs/symptoms and type 2 diabetes. To this end, the cohort was designed to include adequate numbers of US racial/ethnic minorities (Black, Hispanic, White), both men and women, across a broad age of distribution. Follow-up surveys were conducted ∼5 (BACH II, 2008) and 7 (BACH III, 2010) years later, which allows for both within- and between-person comparisons over time. The BACH Survey's measures were designed to cover the following seven broad categories: socio-demographics, health care access/utilization, lifestyles, psychosocial factors, health status, physical measures and biochemical parameters. The breadth of measures has allowed BACH researchers to identify disparities and quantify contributions to social disparities in a number of health conditions including urologic conditions (e.g. nocturia, lower urinary tract symptoms, prostatitis), type 2 diabetes, obesity, bone mineral content and density, and physical function. BACH I data are available through the National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK) Central Repositories (www.niddkrepository.org). Further inquiries can be made through the New England Research Institutes Inc. website (www.neriscience.com/epidemiology).

Vitamin D and the racial difference in the genotype 1 chronic hepatitis C treatment response

BACKGROUND

African Americans with genotype 1 chronic hepatitis C attain a sustained virologic response (SVR) at only approximately one-half the rate of whites after peginterferon and ribavirin treatment. The serum concentration of 25-hydroxyvitamin D [25(OH)D] has recently been established as a predictor of treatment response. Therefore, the low serum concentrations of 25(OH)D found among African Americans may contribute to the low response rate; however, to our knowledge, none of the studies of vitamin D in chronic hepatitis C treatment have included a significant number of black patients.

OBJECTIVE

The objective was to compare the relation between the 25(OH)D concentration and genotype 1 chronic hepatitis C treatment response in African Americans with that in whites.

DESIGN

This cross-sectional analysis included 106 African American and 65 white patients with genotype 1 chronic hepatitis C.

RESULTS

Consistent with previous studies, we found that the SVR rate in the white patients increased significantly with an increasing serum concentration of 25(OH)D [SVR rates were 20%, 46%, and 70% for 25(OH)D serum concentrations <20, 20-35, and >35 ng/mL, respectively; P-trend = 0.008]; however, there was no relation between the SVR rate and 25(OH)D serum concentration in the African American patients [SVR rates were 32%, 28%, and 33% for 25(OH)D serum concentrations <20, 20-35, and >35 ng/mL, respectively; P-trend = 0.832]. We also found an analogous racial difference in the relation between the extent of liver fibrosis and the 25(OH)D concentration.

CONCLUSION

Racial differences in vitamin D physiology or race-specific factors that modify the effects of vitamin D may affect the immune response to genotype 1 hepatitis C virus.

Socioeconomic status, race, and bone turnover in the Midlife in the US Study

Among a group of 940 US adults, economic adversity and minority race status were associated with higher serum levels of markers of bone turnover. These results suggest that higher levels of social stress may increase bone turnover.

INTRODUCTION

To determine socioeconomic status (SES) and race differences in levels of bone turnover.

METHODS

Using data from the Biomarker Substudy of the Midlife in the US (MIDUS) study (491 men, 449 women), we examined cross-sectional associations of SES and race with serum levels of bone turnover markers (bone-specific alkaline phosphatase [BSAP], procollagen type I N-terminal propeptide [PINP], and N-telopeptide [Ntx]) separately in men and women. Linear multivariable regression was used to control for body weight, menopausal transition stage, and age.

RESULTS

Among men, low family poverty-to-income ratio (FPIR) was associated with higher turnover, but neither education nor race was associated with turnover. Men with FPIR <3 had 1.808 nM BCE higher Ntx (P = 0.05), 3.366 U/L higher BSAP (P = 0.02), and 7.066 higher PINP (P = 0.02). Among women, neither education nor FPIR was associated with bone turnover, but Black women had 3.688 nM BCE higher Ntx (P = 0.001), 5.267 U/L higher BSAP (P = 0.005), and 11.906 μg/L higher PINP (P = 0.008) compared with non-Black women.

CONCLUSIONS

Economic adversity was associated with higher bone turnover in men, and minority race status was associated with higher bone turnover in women, consistent with the hypothesis that higher levels of social stresses cause increased bone turnover. The magnitude of these associations was comparable to the effects of some osteoporosis medications on levels of turnover.

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.

Low serum osteocalcin level is a potential marker for metabolic syndrome: results from a Chinese male population survey

Osteocalcin has been recognized as a bone-derived hormone to regulate energy metabolism recently. Little is known about the role of osteocalcin as regards metabolic syndrome (MetS) in a Chinese population. Components of MetS, osteocalcin, body mass index (BMI), and prevalence of MetS were assessed in 2344 men aged 20 to 69 years who participated in the population-based Fangchenggang Area Male Health and Examination Survey, which was carried out in Guangxi province of China from September 2009 to December 2009. Osteocalcin had a statistically significant positive correlation with high-density lipoprotein cholesterol and a negative relationship with blood pressure, glucose, triglycerides, waist circumference, and BMI after adjustment for age (all P < .001). The strongest correlation was observed between osteocalcin and BMI (r = -0.26). In a multivariate analysis, decreased odds ratios (ORs) for the MetS and its components as well were observed from the first to the fourth osteocalcin quartiles. After adjustment for BMI, the OR decreased substantially. Statistically significant difference still existed in MetS (OR, 1.77; 95% confidence interval [CI], 1.10-2.85), hypertriglyceridemia (OR, 1.66; 95% CI, 1.22-2.27), hyperglycemia (OR, 1.42; 95% CI, 1.05-1.92), and low high-density lipoprotein cholesterol (OR, 1.83; 95% CI, 1.03-3.24) when these risks were compared in the lowest quartile of osteocalcin levels with those in the highest quartile. In a Chinese male population, we firstly identified an inverse association of serum osteocalcin levels with MetS, independent from the well-known MetS risk factors. This may represent a further mechanism for the elevated cardiovascular disease or type 2 diabetes mellitus risk.

Racial differences in the relationship between vitamin D, bone mineral density, and parathyroid hormone in the National Health and Nutrition Examination Survey

It is unclear whether optimal levels of 25-hydroxyvitamin D (25(OH)D) in whites are the same as in minorities. In adult participants of NHANES, the relationships between 25(OH)D, bone mineral density (BMD), and parathyroid hormone (PTH) differed in blacks as compared to whites and Mexican-Americans, suggesting that optimal 25(OH)D levels for bone and mineral metabolism may differ by race.

INTRODUCTION

Blacks and Hispanics have lower 25-hydroxyvitamin D concentrations than whites. However, it is unclear whether 25(OH)D levels considered "optimal" for bone and mineral metabolism in whites are the same as those in minority populations.

METHODS

We examined the relationships between 25(OH)D and parathyroid hormone in 8,415 adult participants (25% black and 24% Mexican-American) in the National Health and Nutrition Examination Surveys 2003-2004 and 2005-2006; and between 25(OH)D and bone mineral density in 4,206 adult participants (24% black and 24% Mexican-American) in the 2003-2004 sample.

RESULTS

Blacks and Mexican-Americans had significantly lower 25(OH)D and higher PTH concentrations than whites (P < 0.01 for both). BMD significantly decreased (P < 0.01) as serum 25(OH)D and calcium intake declined among whites and Mexican-Americans, but not among blacks (P = 0.2). The impact of vitamin D deficiency (25(OH)D ≤ 20 ng/ml) on PTH levels was modified by race/ethnicity (P for interaction, 0.001). Whereas inverse relationships between 25(OH)D and PTH were observed above and below a 25(OH)D level of 20 ng/ml in whites and Mexican-Americans, an inverse association between 25(OH)D and PTH was only observed below this threshold in blacks, with the slope of the relationship being essentially flat (P = 0.7) above this cut-point, suggesting that PTH may be maximally suppressed at lower 25(OH)D levels in blacks than in whites or Mexican-Americans.

CONCLUSIONS

The relationships between 25(OH)D, BMD, and PTH may differ by race among US adults. Whether race-specific ranges of optimal vitamin D are needed to appropriately evaluate the adequacy of vitamin D stores in minorities requires further study.

Socioeconomic status and bone health in community-dwelling older men: the CHAMP Study

SUMMARY

The association between socioeconomic status (SES) and bone health, specifically in men, is unclear. Based upon data from the large prospective Concord Health in Ageing Men Project (CHAMP) Study of community-dwelling men aged 70 years or over, we found that specific sub-characteristics of SES, namely, marital status, living circumstances, and acculturation, reflected bone health in older Australian men.

INTRODUCTION

Previous studies reported conflicting results regarding the relationship between SES and bone health, specifically in men. The main objective of this study was to investigate associations of SES with bone health in community-dwelling men aged 70 years or over who participated in the baseline phase of the CHAMP Study in Sydney, Australia.

METHODS

The Australian Socioeconomic Index 2006 (AUSEI06) based on the Australian and New Zealand Standard Classification of Occupations was used to determine SES in 1,705 men. Bone mineral density and bone mineral content (BMC) were determined by dual-energy X-ray absorptiometry. Bone-related biochemical and hormonal parameters, including markers of bone turnover, parathyroid hormone, and vitamin D, were measured in all men.

RESULTS

General linear models adjusted for age, weight, height, and bone area revealed no significant differences across crude AUSEI06 score quintiles for BMC at any skeletal site or for any of the bone-related biochemical measures. However, multivariate regression models revealed that in Australian-born men, marital status was a predictor of higher lumbar BMC (β = 0.07, p = 0.002), higher total body BMC (β = 0.05, p = 0.03), and lower urinary NTX-I levels (β=-0.08, p = 0.03), while living alone was associated with lower BMC at the lumbar spine (β=-0.05, p = 0.04) and higher urinary NTX-I levels (β=0.07, p = 0.04). Marital status was also a predictor of higher total body BMC (β = 0.14, p = 0.003) in immigrants from Eastern and South Eastern Europe. However, in immigrants from Southern Europe, living alone and acculturation were predictors of higher femoral neck BMC (β = 0.11, p = 0.03) and lumbar spine BMC (β = 0.10, p = 0.008), respectively.

CONCLUSIONS

Although crude occupation-based SES scores were not significantly associated with bone health in older Australian men, specific sub-characteristics of SES, namely, marital status, living circumstances, and acculturation, were predictors of bone health in both Australia-born men and European immigrants.

Comparison of bone quantity by ultrasound measurements of phalanges between white and black children living in Paraná, Brazil, with Europeans

The objective of this study was to determine bone quantity by ultrasound measurements of the proximal finger phalanges (AD-SoS = amplitude-dependent speed of sound) of healthy Brazilian schoolchildren living in Paraná, Brazil and to compare these values with European populations. The sample was composed of 1356 Brazilian schoolchildren of both genders (660 males, 696 females), aged 6 to 11 years, divided into white (840) and black (516) groups and compared to age- and gender-matched Europeans. AD-SoS of the schoolchildren increased significantly with age for both genders. Significantly higher AD-SoS values were observed for the white children (1916 ± 58) compared to their black counterparts (1898 ± 72) and for the female gender (1920 ± 61) compared to the male gender (1898 ± 66). Overall, the AD-SoS outcomes for females were similar to those of European studies. However, the AD-SoS of the Brazilian schoolchildren of both genders and skin colors was lower than that reported for children in Poland. AD-SoS outcomes for Brazilian schoolboys were similar to those obtained in Italian studies and were lower than those of the Spanish children. In conclusion, Brazilian schoolchildren of both genders and skin colors showed lower bone quantities than Polish children and Spanish males, and levels similar to Italian children and Spanish females.

Sex and ethnic differences in 47 candidate proteomic markers of cardiovascular disease: the Mayo Clinic proteomic markers of arteriosclerosis study

BACKGROUND

Cardiovascular disease (CVD) susceptibility differs between men and women and varies with ethnicity. This variability is not entirely explained by conventional CVD risk factors. We examined differences in circulating levels of 47 novel protein markers of CVD in 2561 men and women of African-American (AA) and non-Hispanic White (NHW) ethnicity, enrolled at geographically distinct sites.

METHODOLOGY/PRINCIPAL FINDINGS

Participants (1,324 AAs, mean age 63.5 y, 71% women; 1,237 NHWs, mean age 58.9 y, 57% women) belonged to sibships ascertained on the basis of hypertension. Solid-phase immunoassays and immunoturbidometric, clot-based, chromogenic, and electrophoretic assays were used to measure the 47 protein markers in plasma or serum. Marker levels were log transformed and outliers were adjusted to within 4 SD. To identify markers independently associated with sex or ethnicity, we employed multivariable regression analyses that adjusted for conventional risk factors, prior history of CVD, medication use and lifestyle factors (physical activity, alcohol consumption and education). Generalized estimating equations were used to correct for intrafamilial correlations. After adjustment for the above covariates, female sex was associated with higher levels of 29 markers and lower levels of 6 markers. Female sex was independently associated with higher levels of several inflammatory markers as well as lipoproteins, adipokines, natriuretic peptides, vasoconstrictor peptides and markers of calcification and thrombosis. AA ethnicity was associated with higher levels of 19 markers and lower levels of 6 markers, including higher levels of several inflammatory makers, higher leptin and lower adiponectin levels, lower levels of vasodilator-natriuretic peptides, higher levels of vasoconstrictor-antidiuretic peptides and markers of calcification and thrombosis.

CONCLUSIONS/SIGNIFICANCE

Plasma levels of several novel protein markers of CVD differ significantly in the context of sex and ethnicity. These results have implications for individualized CVD risk assessment.

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.

Bone mass in schoolchildren in Brazil: the effect of racial miscegenation, pubertal stage, and socioeconomic differences

The purpose of this study was to evaluate bone mass by phalanges ultrasound in healthy white and black schoolchildren in relationship to socioeconomic level, pubertal stage, and body composition. Included were 1,356 healthy schoolchildren aged from 6 to 11 years from different socioeconomic levels and both genders; all were placed into white and black groups. Weight, height, body mass index, fat percentage, fat mass, and lean mass were evaluated by anthropometric methods, and AD-SoS bone quantity and UBPI bone quality were evaluated using a third-generation IGEA phalanges DBM Sonic BP ultrasound. Data were compared using the Mann-Whitney, chi-squared, correlation coefficient, and analyses of multiple linear regression statistical tests with 5% significance. Black schoolchildren predominated in the low socioeconomic levels. Higher values of weight and height for black boys and girls were observed in the lean mass in relation to white children of the same gender and age. An increasing variation in the bone quantity mean was observed from 6 to 11 years of age and with pubertal stage for both genders and skin color. The white schoolchildren presented higher values of bone quantity and quality in relation to the black children. The anthropometric, gender, and socioeconomic level variables explained only 16 and 11% of the variability of bone quantity and quality, respectively. As such, the present study, carried out with healthy black and white Brazilian schoolchildren, demonstrated higher bone mass, as evaluated by ultrasound, in white than in black schoolchildren.

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

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

Serum 25-hydroxyvitamin D and bone mineral density in a racially and ethnically diverse group of men

CONTEXT

Although racial and ethnic differences in vitamin D status and bone mineral density (BMD) are recognized, less is known about how differences in vitamin D status impact BMD, especially among men.

OBJECTIVE

Our objective was to examine the relation between serum 25-hydroxyvitamin D [25(OH)D] and BMD by race and ethnic group.

DESIGN

We conducted a population-based, observational survey.

PARTICIPANTS

PARTICIPANTS included 1114 Black, Hispanic, and White men, 30-79 yr of age.

OUTCOMES

We assessed 25(OH)D by a competitive protein binding assay and BMD by dual-energy x-ray absorptiometry.

RESULTS

Mean age +/- SD of the 331 Black, 362 Hispanic, and 421 White men was 48 +/- 12.8 yr. Mean 25(OH)D was lower among Black (25.0 +/- 14.7 ng/ml) and Hispanic (32.9 +/- 13.9 ng/ml) men compared with White men (37.4 +/- 14.0 ng/ml, P < 0.01). A higher percentage of both Black (44%) and Hispanic (23%) men had levels of 25(OH)D in the lowest quartile, compared with 11% of White men (P < 0.001). After adjusting for age, height, and weight, only White men showed significant positive correlation between 25(OH)D and BMD (range of correlations, 0.00-0.14). Serum 25(OH)D was not associated with BMD in Black or Hispanic men at any bone site. Results were similar when adjusted for age only.

CONCLUSIONS

Our findings confirm substantial racial and ethnic group differences in BMD and serum 25(OH)D in men. Serum 25(OH)D and BMD are significantly related to one another in White men only. This may have implications for evaluation of bone health and supplementation in men with low levels of 25(OH)D. Further understanding of the biological mechanisms for these differences between race and ethnic groups is needed.