Differential effects of menopause and metabolic disease on trabecular and cortical bone assessed by peripheral quantitative computed tomography (pQCT)

Menopause is associated with bone loss, particularly at the distal radius, in black South African women: Findings from the Study of Women Entering and in Endocrine Transition (SWEET)

Menopause transition is associated with accelerated bone loss, though data are limited from sub-Saharan African (SSA). Our objective was to describe bone density, geometry and estimated strength in women by menopause status and to explore whether patterns differed within those living with HIV.

METHODS

Radius and tibia peripheral QCT data were collected for Black South African women (n = 430) aged 40-61 years with verified menopause and HIV status. pQCT outcomes were distal 4 % radius and tibia total cross-sectional area (CSA), total volumetric bone mineral density (vBMD), and compressive bone strength (BSIc); proximal 66 % radius and 38 % tibia cortical vBMD, total CSA, cortical thickness, and Stress-strain Index (SSI). Linear regression assessed associations between pre, peri-, and postmenopausal groups and pQCT outcomes adjusting for age, height, and weight, and then stratified by HIV status. Mean [95%CI] and tests for trend (p-trend) across menopausal groups are presented.

RESULTS

Women were mean (SD) age 49.2 (5.3) years, with a body mass index (BMI) of 32.4 (6.3) m/kg², and 18 % were living with HIV. After adjustment, later menopause stage was associated with lower 4 % radius total mean [95%CIs] vBMD (premenopause: 345.7 [335.8,355.5] vs. postmenopause: 330.1 [322.7,337.6] mg/cm³, p-trend = 0.017) and BSIc (premenopause: 0.39 [0.37,0.41] vs. postmenopause: 0.36 [0.35,0.37] g²/cm⁴; p-trend = 0.012). Similar trends were observed at the 66 % radius for cortical vBMD (premenopause: 1146.8 [1138.9,1154.6] vs. postmenopause: 1136.1 [1130.1,1142.0] mg/cm³; p-trend = 0.028) and cortical thickness (premenopause: 2.01 [1.95,2.06] vs. postmenopause: 1.93 [1.89,1.98] mm; p-trend = 0.036). After stratification by HIV status a similar patten was observed in women with HIV (cortical vBMD premenopause: 1152.9 [1128.5,1177.2] mg/cm³ vs. postmenopause: 1123.6 [1106.0,1141.2] mg/cm³, p-trend = 0.048). Total CSA varied little by menopause or HIV status at either radius sites; few differences were found at the tibia.

CONCLUSION

In black South African women, menopause is associated with lower bone density and strength at the distal radius, a common site of osteoporotic fracture, in addition to lower cortical density and thickness at the proximal radius. Although the sample size was small, following stratification by HIV, women living with HIV had evidence of lower cortical density across menopause stages, unlike those without HIV. These findings raise concern for the incidence of Colles' fractures in postmenopausal women in South Africa; longitudinal studies of fracture incidence and implications of living with HIV are required.

Meta-analyses of the quantitative computed tomography data in dialysis patients show differential impacts of renal failure on the trabecular and cortical bones

Dialysis patients have compromised bone health that increases their fracture risk due to low bone mass and deterioration in bone microarchitecture. Through meta-analyses of published studies, we conclude that dialysis patients suffer from impaired compartmental bone parameters compared with healthy controls.

INTRODUCTION

We performed meta-analyses to determine the effect of chronic kidney disease (CKD) patients under dialysis on the trabecular and cortical parameters of radius and tibia.

METHODS

This is a meta-analysis of cross-sectional and prospective clinical studies. PubMed, Web of Science, Google Scholar, and Scopus were searched using various permutation combinations. Dialysis patients were compared with non-CKD healthy controls using quantitative computed tomography. High-resolution peripheral quantitative computed tomography (HR-pQCT) and pQCT data of dialysis patients were dissected from eligible studies for pooled analysis of each parameter.

RESULTS

Ten studies met the inclusion criteria that included data from 457 dialysis patients and 2134 controls. Pooled analysis showed a significant decrease (a) in total vBMD at distal radius [standard deviation of the mean (SDM) = -0.842, p = 0.000] and tibia (SMD = -0.705, p = 0.000) and (b) in cortical vBMD (SDM = -1.037, p = 0.000) at radius of dialysis patients compared with control. There were strong correlations between total vBMD and microarchitecture parameters at tibia in dialysis patients.

CONCLUSIONS

At radius and tibia, bone mass, microarchitecture, and geometry at trabecular and cortical envelopes displayed impairments in dialysis patients compared with control. Tibial vBMD may have diagnostic value in dialysis. HR-pQCT and pQCT may be used to further understand the compartmental bones response to CKD-induced loss at different stages of CKD.

Bone mineral density and osteoporosis risk in young adults with atopic dermatitis

Atopic dermatitis (AD) has been increasing worldwide over the past few decades. AD has been reported to be associated with an increased risk of osteoporosis and fractures in adult AD patients. The aim of this study was to investigate the bone mineral density (BMD) to evaluate osteoporosis risk in young adults with AD by sex. This was a case-control cohort study using a national dataset from the Korea National Health and Nutrition Examination Survey 2007-2009. We included young adult AD patients (men aged 19 ≤ and < 50 years, premenopausal women aged 19 ≤ and < 50 years) and 1:5 propensity score weighting controls by age, sex, body mass index (BMI), vitamin D level, and alcohol/smoking status. BMD was measured by double energy X-ray absorptiometry at the lumbar spine, femur neck, and total femur. The prevalence of low BMD, defined by a Z-score ≤  - 2.0, was compared between AD and without AD. We analyzed 311 (weighted n = 817,014) AD patients and 8,972 (weighted n = 20,880,643) controls. BMD at the lumbar spine was significantly lower in the male AD group than in the male control group (mean ± SE, 0.954 ± 0.016 vs. 0.989 ± 0.002, P = 0.03). The prevalence of low BMD (Z-score) did not significantly differ between AD and non-AD subjects in both men (3.8% vs. 2.7%, P = 0.56) and women (6.4% vs. 3.3%, P = 0.40). Among AD patients, early age at diagnosis of AD, longer duration of AD, lower BMI, rural residence (for men), less education, low vitamin D level, late menarche, and more pregnancies (for women) were associated with low BMD. In conclusion, low BMD did not occur more frequently in young adults with AD than in non-AD controls. However, early-onset/longer AD duration and lower BMI were associated with low BMD among young adult patients with AD.

Effect of exercise on slowing breastfeeding-induced bone loss: A meta-analysis and trial sequential analysis

AIM

This study systematically reviewed evidence regarding the effectiveness of exercise in slowing breastfeeding-induced bone loss.

METHODS

The evidence-based approach of a systematic review (PROSPERO registration No. CRD42019111623) was adopted. The inclusion criteria were randomized controlled trials or observational studies. Study samples were breastfeeding women, the intervention was any form of exercise, and bone mineral density (BMD) of the total body, lumbar spine and hip/femur neck before 6 months and at 1 year were the outcome measures. Meta-analyses were performed using a random effect model, and calculations of mean differences of BMD change and 95% confidence intervals (CIs) were carried out. Studies were further evaluated through trial sequential meta-analysis (TSA), and the 'Grading of Recommendations Assessment, Development and Evaluation' methodology was used to assess the certainty of evidence (CoE).

RESULTS

A total of 1049 studies were screened, and 4 met the inclusion criteria. Weight-bearing aerobic exercise and resistance training before the 6-month evaluation slowed breastfeeding-induced bone loss in the lumbar spine (1.62% BMD change [95% CI = 0.53-2.71]; I² = 8%). The TSA Z-curve revealed crossing of the TSA boundary and line of information size, indicating sufficient sampling and significance. The CoE of exercise benefit in the lumbar spine at 6 months was low, whereas the CoE for other areas ranged from low to very low.

CONCLUSION

This first systematic review and meta-analysis provided some evidence of the advantages of exercise for slowing breastfeeding-induced bone loss. However, additional randomized controlled trials are warranted to generate more conclusive evidence.

Effect of Primary Hypertension on Treatment Outcomes of Patients with Postmenopausal Osteoporosis: A 5 Year Follow Up Retrospective Study

AIM

To investigate the efficacy of primary hypertension (HTN) on the treatment prognosis of patients with postmenopausal osteoporosis (PMOP).

METHODS

45 patients who were diagnosed as PMOP with lumbar and/or femur neck bone mineral density screening (BMD) but have no history of PMOP treatment including calcium and vitamin D, have comorbid primary HTN and treated with a vasodilator antihypertensive drug at least a year were included to the study. Control group was constituted with 44 patients with PMOP at same age but have no comorbidity. Demographic features including age, height, weight, occupation, educational level menarche and menopause age, clothing style, daily intake of calcium, smoking and/or alcohol consumption, daily physical activity level, personal history of fragility fracture or in mother and duration of primary HTN diagnosis were recorded. Biochemical parameters were also recorded. Patients were treated with bisphosphonate, calcium and vitamin D and same parameters were evaluated at the end of first and fifth year.

RESULTS

Demographic and disease characteristics were not different between groups before treatment (p > 0.05). In group analysis, there was significant improvement in lumbar and femur neck T scores of PMOP + HT and PMOP groups after 1 and 5 years of treatment compared to baseline (p < 0.05) Lumbar and femur neck T score variations between the baseline, first and fifth years of treatment were not significantly different in PMOP + HT and PMOP groups (p < 0.05).

CONCLUSIONS

Although the results vary between populations, primary HTN does not have an impact on the prognosis of PMOP treatment in Turkish population.

Evaluating Weight Status and Sex as Moderators of the Association of Serum Leptin with Bone Mineral Density in Children and Adolescents

BACKGROUND/AIMS

Animal studies suggest that leptin may adversely affect bone mineral density (BMD). Clinical studies have yielded conflicting results. We therefore investigated associations between leptin and bone parameters in children.

METHODS

830 healthy children (age = 11.4 ± 3.1 years; 75% female; BMI standard deviation score [BMIz] = 1.5 ± 1.1) had fasting serum leptin measured with ELISA and body composition by dual-energy X-ray absorptiometry. The main effects for leptin and BMIz plus leptin's interactions with sex and BMIz were examined using hierarchical linear regressions for appendicular, pelvis, and lumbar spine BMD as well as bone mineral content (BMC), and bone area (BA).

RESULTS

Accounting for demographic, pubertal development, and anthropometric variables, leptin was negatively and independently associated with lumbar spine BMC and BA, pelvis BA, and leg BA (p < 0.05 for all). Sex, but not BMIz, moderated the associations of leptin with bone parameters. In boys, leptin was negatively correlated with leg and arm BMD, BMC at all bone sites, and BA at the subtotal and lumbar spine (p < 0.01 for all). In girls, leptin was positively correlated with leg and arm BMD (p < 0.05 for both).

CONCLUSION

Independent of body size, leptin is negatively associated with bone measures; however, these associations are moderated by sex: boys, but not girls, have a negative independent association between leptin and BMD.
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A Comparison of Peripheral Imaging Technologies for Bone and Muscle Quantification: a Mixed Methods Clinical Review

PURPOSE OF REVIEW

Bone and muscle peripheral imaging technologies are reviewed for their association with fractures and frailty. A narrative systematized review was conducted for bone and muscle parameters from each imaging technique. In addition, meta-analyses were performed across all bone quality parameters.

RECENT FINDINGS

The current body of evidence for bone quality's association with fractures is strong for (high-resolution) peripheral quantitative computed tomography (pQCT), with trabecular separation (Tb.Sp) and integral volumetric bone mineral density (vBMD) reporting consistently large associations with various fracture types across studies. Muscle has recently been linked to fractures and frailty, but the quality of evidence remains weaker from studies of small sample sizes. It is increasingly apparent that musculoskeletal tissues have a complex relationship with interrelated clinical endpoints such as fractures and frailty. Future studies must concurrently address these relationships in order to decipher the relative importance of one causal pathway from another.

Association between bone indices assessed by DXA, HR-pQCT and QCT scans in post-menopausal women

Quantitative computed tomography (QCT), high-resolution peripheral QCT (HR-pQCT) and dual X-ray absorptiometry (DXA) scans are commonly used when assessing bone mass and structure in patients with osteoporosis. Depending on the imaging technique and measuring site, different information on bone quality is obtained. How well these techniques correlate when assessing central as well as distal skeletal sites has not been carefully assessed to date. One hundred and twenty-five post-menopausal women aged 56-82 (mean 63) years were studied using DXA scans (spine, hip, whole body and forearm), including trabecular bone score (TBS), QCT scans (spine and hip) and HR-pQCT scans (distal radius and tibia). Central site measurements of areal bone mineral density (aBMD) by DXA and volumetric BMD (vBMD) by QCT correlated significantly at the hip (r = 0.74, p < 0.01). Distal site measurements of density at the radius as assessed by DXA and HR-pQCT were also associated (r = 0.74, p < 0.01). Correlations between distal and central site measurements of the hip and of the tibia and radius showed weak to moderate correlation between vBMD by HR-pQCT and QCT (r = -0.27 to 0.54). TBS correlated with QCT at the lumbar spine (r = 0.35) and to trabecular indices of HR-pQCT at the radius and tibia (r = -0.16 to 0.31, p < 0.01). There was moderate to strong agreement between measuring techniques when assessing the same skeletal site. However, when assessing correlations between central and distal sites, the associations were only weak to moderate. Our data suggest that the various techniques measure different characteristics of the bone, and may therefore be used in addition to rather than as a replacment for imaging in clinical practice.

Relationship between breast-feeding and bone mineral density among Korean women in the 2010 Korea National Health and Nutrition Examination Survey

Breast-feeding has the deleterious effect of hypoestrogenemia coupled with loss of calcium in the maternal bone mass. It is not clear whether changes in bone metabolism in lactating women lead to changes in maternal bone mineral density (BMD) over a longer period. The aim of the present study was to investigate the relationship between the duration of breast-feeding and BMD in healthy South Korean women. We analyzed data from the 2010 Korea National Health and Nutrition Examination Survey, a cross-sectional survey of Korean citizens. A total of 1342 women older than 19 years were selected for analysis. In postmenopausal women, the duration of breast-feeding per child was associated with low lumbar spine BMD after adjustment for age, body mass index, smoking, alcohol intake, physical activity, serum 25-hydroxyvitamin D level, and daily intake of calcium and calories (P < 0.05, P trend < 0.005). Prolonged breast-feeding for more than 1 year per child was associated with a deleterious effect on lumbar spine BMD compared with never breast-feeding or a shorter duration of breast-feeding (P < 0.05). These effects were not shown in premenopausal women or in femur BMD. In conclusion, the duration of breast-feeding per child is negatively correlated with lumbar spine BMD in postmenopausal women, but not in premenopausal women. Although the cause of the different results between postmenopausal and premenopausal women is not clear, our findings suggest that proper protective strategies should be recommended during prolonged breast-feeding to maintain bone health later in life.

Android shape independent of aerobic fitness: a risk factor for low bone mineral content in overweight and obese latina women

OBJECTIVE

The link between central adiposity and osteopenia has not been extensively studied in Latina women. In particular, the association between abdominal weight and bone mineral content (BMC) and bone mineral density (BMD), independent of total weight and aerobic capacity, remains uncertain, especially in overweight and obese individuals.

METHODS

Trunk weight, total body fat mass, fat-free mass, BMC, and BMD of 33 premenopausal Latina women age 22 to 51 years from Los Angeles, California were measured using dual-energy X-ray absorptiometry (DXA). Waist circumference (WC) was measured without clothing at the smallest circumference of the torso. Peak aerobic capacity (peak VO2) was determined by treadmill ergometry with direct measurement of oxygen consumption.

RESULTS

Partial correlations controlling for total body fat mass, fat-free mass, and peak VO2 revealed a significant inverse relationship between BMC and WC (r = -0.54, P < 0.05) but not between BMD and WC (r = -0.18, P = 0.41). Similarly, while controlling for total body fat, fat-free mass, and peak VO2, BMC was inversely associated with trunk fat (r = -0.75, P < 0.001), with trunk lean (r = -0.61, P < 0.05) and with total trunk weight (r = -0.75, P < 0.001); results were non-significant for BMD. When these analyses were repeated separately in overweight (n = 10) versus in the obese (n = 18) women, inverse relationships between BMC and trunk fat as well as between BMC and total trunk weight became stronger in the obese compared with the overweight women.

CONCLUSION

Although general obesity may prevent osteoporosis, these findings suggest that abdominal obesity (ie, trunk weight) specifically and independently may adversely influence bone mass.

Age and sex differences in tibia morphology in healthy adult Caucasians

Variability in peripheral Quantitative Computed Tomography (pQCT) measurement sites limits direct comparisons of results between studies. Further, it is unclear what estimates of bone strength are most indicative of changes due to aging, disease, or interventions. The purpose of this study was to examine age group and sex differences in tibia morphology. Additional purposes of this study were to determine which tibia site or sites are most sensitive for detecting age and sex differences.

METHODS

Self-identifying Caucasian men (n=55) and women (n=59) ages 20-59 years and separated by decades had their non-dominant tibias measured with pQCT (Stratec XCT 3000) at every 10% of the limb length from 5% to 85% (distal to proximal). Volumetric BMD and BMC of the total, cortical and trabecular bone were determined, as well as periosteal (PeriC) and endosteal (EndoC) circumferences, and cortical thickness (CTh).

RESULTS

There were significant (p<0.01) site effects for all BMC, vBMD, PeriC and EndoC measures. Large sex differences (men>women) in Tot.BMC (21-28%) were paralleled by differences in Cort.BMC (21-25%) (p<0.01). Site∗sex interaction effects were significant (p<0.05) for BMC (peak sex difference: 5%, 15%, 25%, 85% sites) and circumference (peak sex difference: 65% site) variables. CTh and total vBMD were lowest (p<0.05) in 50-59 year group, and EndoC was highest in the 50-59 year group. Site∗age interactions existed for Cort.vBMD, Tot.BMC (85% site), and EndoC (25%, 35%, 55%-85% sites). Correcting for bone free lean body mass (BFLBM) greatly reduced sex differences, eliminating sex∗site interaction effects, but sex main effects remained significant. Correcting for BFLBM did not eliminate age effects.

CONCLUSION

The magnitude of age and sex differences in tibia variables varied by measurement site demonstrating the need for standardization of measurement sites.

Anemia as a risk factor for low bone mineral density in postmenopausal Turkish women

BACKGROUND

We investigated the association of bone mineral density (BMD) by detected dual-energy X-ray absorptiometric (DXA) method and hemoglobin (Hb) levels in a large sample.

METHODS

The current study enrolled 371 postmenopausal women (82 anemic patients), who were screened for osteopenia or osteoporosis by DXA. Patients with osteopenia or osteoporosis (T score<-1.0 SD) were grouped as having low bone mass (LBM).

RESULTS

Anemic patients were older and had significantly higher duration of menopause. When compared with subjects with normal Hb, anemic patients had significant lower femur t score, femur BMD, femur Z score, spinal t score, spinal BMD and spinal Z score (p<0.001). Additionally, the ratio of subjects with LBM in the femur and spine were significantly high in anemic patients (p<0.002, p<0.002, respectively). There were significant correlations between Hb values and femur t score, femur BMD, spine t score, and spine BMD values of the study population in bivariate correlation analysis (r=0.150, p=0.004, r=0.148, p=0.004, r=0.160, p=0.002, r=0.164, p=0.001, respectively). Furthermore, presence of anemia was found to be an independent predictor of LBM for spine [OR: 2.483 (95% CI: 1.309-4.712), p<0.005] in logistic regression analysis. Additionally, number of anemic patients was significantly high in low femur and spine BMD groups (56 vs. 26; p=0.01, 66 vs. 16; p=0.002, respectively).

CONCLUSION

We have found that the presence of anemia was as an independent predictor of LBM for spine after adjusting for body mass index and other confounders in postmenopausal Turkish women.

Association of hypertension and bone mineral density in an elderly African American female population

BACKGROUND

Recent studies have shown that hypertension is inversely correlated with bone mineral density (BMD) as determined by dual energy x-ray absorptiometery (DXA) in different ethnic groups. But in most published studies, either the sample size was small or the study was limited by different measurement methods. These limitations leave this association controversial and inconclusive. The current study utilizes a sample of African American females referred for clinical screening of osteoporosis in our center to find out if any association of high blood pressure and BMD in this ethnic group exists. The secondary endpoint was to determine the effect of thiazide diuretics on BMD of the elderly African American females because, theoretically, thiazides are considered to have a positive impact on BMD.

METHODS

In this retrospective, cross-sectional study, 10 years of data were reviewed from 1113 medical records of African American females aged 65 years and older whose BMD values were measured by DXA at the lumbar spine (L1-L4) and both femoral necks (the standard sites for BMD determination) along with their T scores and Z scores (used to determine osteopenia vs osteoporosis). Our exclusion criteria included patients who: (1) were current smokers, (2) had a previous oophorectomy, (3) had a history of corticosteroid use, (4) had a history of biphosphonate use, (5) were on hormone replacement therapy, and (6) were diabetic and taking either pioglitazones or roziglitazones. A total of 148 patients were excluded from the analysis due to either incomplete data or exclusion criteria. The remaining sample was then divided into 2 groups based on their hypertensive status. For the subanalysis, the hypertensive group was further divided into 2 additional groups based on their thiazide usage.

RESULTS

We had complete data on 965 participants, of which 631 (65.3%) had a history of hypertension and 334 (34.7%) did not. Out of 631 hypertensive patients, 173 were found to be using thiazide diuretics as antihypertensive medication, while 458 were without thiazide diurectic use. The proportion of patients with both osteopenia and osteoporosis was similar in those with and without hypertension (50% vs 50%, p = .95 for osteopenia; 18% vs 19%, p = .95 for osteoporosis). There was no significant difference between the BMD at the lumbar spine, and right and left femoral necks between patients with and without hypertension. This lack of association held true when comparing the mean T scores and Z scores at the above sites. Within patients with a history of hypertension, there were no significant differences in the BMD, T score or Z score at any site with and without a history of thiazide diuretic use.

CONCLUSION

Hypertension in elderly African American females aged at least 65 years was not found to be correlated with low BMD at either the lumbar spine (L1-L4) or both femoral necks when confounding factors were taken into consideration. Mean BMD of the hypertensive cohort taking thiazide diuretics was found lower at the lumbar spine as compared to the hypertensive patients not taking thiazide diuretics.

Epidemiology and structural basis of racial differences in fragility fractures in Chinese and Caucasians

Chinese have similar vertebral fracture prevalence but lower incidence of hip and distal forearm fractures than in Caucasians. The underlying structural and biomechanical basis of racial differences in bone fragility is still largely undefined but Chinese assemble their smaller appendicular skeleton with thicker cortices and trabeculae compared with Caucasians. Vertebral fracture prevalence is similar by race, but the incidence of hip and distal forearm fractures is lower in Chinese than in Caucasians. This racial dimorphism cannot be explained by differences in areal bone mineral density (aBMD) as aBMD is lower in Chinese mainly due to their smaller size. The underlying structural and biomechanical basis of racial differences in bone fragility is still largely undefined but Chinese assemble their smaller appendicular skeleton with more mineralised bone matrix within it; the cortices are thicker and perhaps less porous while trabeculae are fewer but thicker and more connected. This configuration produces a bone with a lower surface/volume ratio, which in turn reduces the surface available for remodelling to occur upon so that the lower surface/volume ratio may make the bone less exposed to remodelling and the thicker cortices and trabeculae less vulnerable to remodelling when it does occur during advancing age. However, prospective studies are needed to define racial differences at the age of onset, rate of bone loss from the intracortical, endocortical and trabecular components of the endosteal envelope and bone formation upon the periosteal envelope; notions of bone 'loss' are derived mainly from cross-sectional studies. Studies of the site- and surface-specific changes in bone modelling and remodelling are needed to better define racial differences in bone fragility in old age.

Seasonal change in bone, muscle and fat in professional rugby league players and its relationship to injury: a cohort study

OBJECTIVES

To examine the anthropometric characteristics of an Australian National Rugby League team and identify the relationship to type and incidence of injuries sustained during a professional season. It was hypothesised that body composition would not change discernibly across a season and that injury would be negatively related to preseason bone and muscle mass.

DESIGN

A repeated measure, prospective, observational, cohort study.

SETTING

Griffith University, Gold Coast, Australia.

PARTICIPANTS

37 professional male Australian National Rugby League players, 24.3 (3.8) years of age were recruited for preseason 1 testing, of whom 25 were retested preseason 2.

PRIMARY AND SECONDARY OUTCOME MEASURES

Primary outcome measures included biometrics; body composition (bone, muscle and fat mass; dual-energy x-ray absorptiometry; XR800, Norland Medical Systems, Inc); bone geometry and strength (peripheral quantitative CT; XCT 3000, Stratec); calcaneal broadband ultrasound attenuation (BUA; QUS-2, Quidel); diet and physical activity history. Secondary outcome measures included player injuries across a single playing season.

RESULTS

Lean mass decreased progressively throughout the season (pre=81.45(7.76) kg; post=79.89(6.72) kg; p≤0.05), while whole body (WB) bone mineral density (BMD) increased until mid-season (pre=1.235(0.087) g/cm(2); mid=1.296(0.093) g/cm(2); p≤0.001) then decreased thereafter (post=1.256(0.100); p≤0.001). Start-of-season WB BMD, fat and lean mass, weight and tibial mass measured at the 38% site predicted bone injury incidence, but no other relationship was observed between body composition and injury.

CONCLUSIONS

Significant anthropometric changes were observed in players across a professional rugby league season, including an overall loss of muscle and an initial increase, followed by a decrease in bone mass. Strong relationships between anthropometry and incidence of injury were not observed. Long-term tracking of large rugby league cohorts is indicated to obtain more injury data in order to examine anthropometric relationships with greater statistical power.

The effect of breast-feeding duration on bone mineral density in postmenopausal Turkish women: a population-based study

INTRODUCTION

In the present study, we investigated the effects of breast-feeding time on bone mineral density (BMD) later in life.

MATERIAL AND METHODS

The current study was based on a retrospective analysis of 586 postmenopausal women with a mean age of 60.8 years, who were screened for osteoporosis by dual energy X-ray absorptiometry (DXA).They were classified into 4 groups with respect to the duration of their breast-feeding as never (group 1), 1-24 months (group 2), 25-60 months (group 3), or > 60 months (group 4). Bone mineral density results for the femur neck and lumbar spine were classified into 3 groups according to WHO criteria as normal (T score > -1.0 SD), osteopenia (T score -1.0 to -2.5 SD), and osteoporosis (T score < -2.5 SD). Patients with osteopenia or osteoporosis (T score < -1.0 SD) were considered as having low bone mass (LBM).

RESULTS

We found a correlation between duration of lactation and femur BMD or spine BMD in the study population (r = 0.116, p < 0.005; r = -0.151, p = 0.001, respectively). Significant differences were found between femur BMD and spine BMD of groups in one-way ANOVA analysis (p = 0.025, p = 0.005, respectively). Additionally, when compared with the other three groups, group 4 was older and had longer duration of menopause (p < 0.01). In logistic regression analysis, age and body mass index were found as independent risk factors of LBM [odds ratio: 1.084 (95% CI 1.031-1.141); odds ratio: 0.896 (95% CI 0.859-0.935)], while duration of lactation was not found as an independent predictor of LBM.

CONCLUSIONS

In this study, we have found that changes of bone metabolism during lactation had no effect on postmenopausal BMD measured by DXA. Consequently, it can be suggested that long breast-feeding duration is not a risk factor for low bone mass later in life.

Relationship between blood pressure levels and bone mineral density in postmenopausal Turkish women

INTRODUCTION

We investigated the association between bone mineral density (BMD) detected by dual-energy X-ray absorptiometric (DXA) method and blood pressure (BP) in a large sample of postmenopausal women.

MATERIAL AND METHODS

The current study was based on a retrospective analysis of 586 postmenopausal women with a mean age of 60.8 ±8.8 years, who were screened for osteopenia or osteoporosis by DXA. Patients with hypertension (HT, n= 306) were compared with normotensive (NT, n = 290) individuals. Bone mineral density results for the femur neck and spine were classified into 3 groups according to World Health Organization criteria: normal (T score > -1.0 SD), osteopenia (T score -1.0 to -2.5 SD) and osteoporosis (T score < -2.5 SD). Patients with osteopenia or osteoporosis (T score < -1.0 SD) were grouped as having low bone mass (LBM).

RESULTS

There were no significant differences in femur T score, femur BMD, femur Z score, spinal T score, spinal BMD and spinal Z score between hypertensive and normotensive groups. The group of patients with low bone mass calculated from femur T scores had higher age, systolic BP, duration of hypertension and duration of menopause, but lower BMI. Similarly, patients with low spine BMD had higher age and duration of menopause, but lower BMI. Linear regression analysis showed a significant correlation between systolic BP and femur BMD and T score values. Furthermore, logistic regression analysis revealed that hypertension is an independent predictor of spinal osteopenia and osteoporosis.

CONCLUSIONS

The presence of hypertension is an independent predictor of spinal low bone density in Turkish women after menopause.

Recent progress in bone imaging for osteoporosis research

Advances in bone imaging techniques have provided tools for analyzing bone structure at the macro-, micro- and nano-level. Quantitative assessment of macrostructure can be achieved using dual X-ray absorptiometry (DXA) and quantitative computed tomography (QCT), particularly volumetric quantitative CT (vQCT). In vivo quantitative techniques for assessing the microstructure of trabecular bone non-invasively and non-destructively include high-resolution CT (HR-CT) and high-resolution magnetic resonance (HR-MR). Compared with MR imaging, CT-based techniques have the advantage of directly visualizing the bone in the axial skeleton, with high spatial resolution, but the disadvantage of delivering a considerable radiation dose. Micro-CT (μCT), which provides a higher resolution of the microstructure and is principally applicable in vitro, has undergone technological advances such that it is now able to elucidate the physiological skeletal change mechanisms associated with aging and determine the effects of therapeutic intervention on the bone microstructure. In particular, synchrotron μCT (SR-CT) provides a more detailed view of trabecular structure at the nano-level. For the assessment of hip geometry, DXA-based hip structure analysis (HSA) and CT-based HSA have been developed. DXA-based HSA is a convenient tool for analyzing biomechanical properties and for assuming cross-sectional hip geometry based on two-dimensional (2D) data, whereas CT-based HSA provides these parameters three-dimensionally in robust relationship with biomechanical properties, at the cost of greater radiation exposure and the lengthy time required for the analytical procedure. Further progress in bone imaging technology is promising to bring new aspects of bone structure in relation to bone strength to light, and to establish a means for analyzing bone structural properties in the everyday clinical setting.

Age-related differences of bone mass, geometry, and strength in treatment-naïve postmenopausal women. A tibia pQCT study

Most studies addressing the effects of aging on bone strength have focused mainly on (areal) bone mineral densities and bone mineral content (BMC) and less on bone geometry. We assessed age-related differences of bone mass (grams of bone mineral), geometry, and derived strength in 219 treatment-naïve postmenopausal women using peripheral quantitative computed tomography of the load-bearing tibia. Subjects were separated in 3 age groups: A=48-59yr (N=80), B=60-69yr (N=84), C=70-80yr (N=55). Three slices were obtained for each individual, at the 4% (trabecular), 14% (subcortical and cortical), and 38% (cortical bone) of tibia length sites. Trabecular, subcortical, and cortical BMC (mg per 1-mm slice), volumetric bone mineral densities (mg/cm(3)), bone cross-sectional areas (mm(2)), periosteal (PERI_C, mm) and endosteal circumference (ENDO_C, mm), mean cortical thickness (CRT_THK, mm), and Stress Strain Indexes (SSIs, mm(3)) were studied. Trabecular and cortical BMC and volumetric densities were significantly lower in the elder subjects (group C) compared with younger subjects (groups A and B), p<0.0005. Cortical area and CRT_THK were significantly lower in group C (vs A and B, p<0.0005), whereas total cross-sectional area was higher in group C compared with A and B. ENDO_C was significantly higher in older subjects (group C vs A and B, p<0.0005), whereas PERI_C did not differ significantly between the age groups. SSIs were significantly lower in older subjects at the 14% site (group C vs A, p<0.0005 and C vs B, p<0.005), and at the 38% site (group C vs group A, p<0.01). Our results indicate that age-induced differences on bone strength entail significant alterations not only of bone mass, but also of bone geometry.

Bone disease in elderly individuals with CKD

Bone disease can lead to significant morbidity and mortality for those who are afflicted by it, irrespective of etiology. Two very prevalent causes of bone disease that contribute to this are osteoporosis and chronic kidney disease (CKD). The modern era has seen important advances in the understanding and management of these processes, but in elderly patients with CKD it remains a complex issue that has yet to be clearly defined. Changes in mineral metabolism that accompany the loss of renal function result in a spectrum of bone disease that occurs concomitantly with bone loss secondary to aging. As such, the traditional paradigms used to manage bone disease may not be appropriate for these patients. With the aging dialysis population, a better understanding of these 2 processes and their interplay deserves more attention.

Reproducibility of peripheral quantitative computed tomography measurements at the radius and tibia in healthy pre- and postmenopausal women

PURPOSE

The objectives of this study were to utilise the XCT-2000 pQCT scanner to determine the mean values and the reproducibility of in vivo total, trabecular, and cortical volumetric bone measurements at distal and diaphyseal sites of the radius and the tibia, as well as calf muscle and subcutaneous fat areas, in healthy pre- and postmenopausal women.

METHODS

Twenty-nine women (14 premenopausal and 15 postmenopausal) were recruited to participate in this study. Distal and diaphyseal sites of the radius (at 4% and 20% of the length of the radius) and tibia (at 4%, 38%, and 66% of the length of the tibia) were examined.

RESULTS

The root mean square coefficient of variation for measurements at the distal tibia gave the most favorable reproducibility values for total (1.5%) and trabecular (1.6%) density, whereas the diaphyseal tibia showed the most favorable reproducibility value for cortical density (0.3%). The root mean square coefficients of variation for measurements of muscle and fat cross-sectional areas at the calf were 0.6% and 0.7%, respectively. At the distal tibia, the mean values for total (P < .05) and trabecular (P < .01) density were significantly lower in postmenopausal women than in premenopausal women.

CONCLUSIONS

The data presented here indicate that XCT-2000 pQCT scans at the tibia provide highly reproducible measurements of total, cortical, and trabecular bone as well as muscle and fat cross-sectional areas. Furthermore, significant differences in volumetric bone measurements between healthy pre- and postmenopausal women were evident only at the distal tibia, suggesting that this site warrants further study.

Differences in regional bone perfusion and turnover between lumbar spine and distal humerus: (18)F-fluoride PET study of treatment-naïve and treated postmenopausal women

The functional imaging technique of (18)F-fluoride positron emission tomography ((18)F-PET) allows the non-invasive assessment of regional bone blood perfusion and turnover. Bone perfusion and turnover measured using (18)F-PET correlate closely with those obtained experimentally and so they can be readily applied in clinical research studies. The aim of this study was to compare bone perfusion and turnover between the lumbar spine and humerus in both treatment naïve postmenopausal women (n=11) and those on stable antiresorptive therapy (n=12). All women had a BMD T-score of less than -2 at the spine and/or hip. Each woman had a dynamic PET scan of the lumbar spine and distal humerus after injection of 90 MBq (18)F-fluoride. Using a three-compartmental model bone perfusion (K(1)), the net plasma clearance of tracer to bone mineral (K(i)) reflecting regional bone turnover and the rate constants k(2)-k(4) describing the transport of fluoride between plasma, an extravascular bone compartment and bone mineral compartment were calculated. Mean bone perfusion (K(1)) and bone turnover (K(i)) were significantly higher at the lumbar spine compared to the humerus for both treatment-naïve and antiresorptive groups. K(1) values were on average 3 times greater while K(i) was approximately 50% greater at the lumbar spine. The rate constant k(2), the reverse transport of fluoride from the extravascular compartment to plasma, was significantly lower at the humerus compared to the lumbar spine in both groups. The ratio K(i)/K(1) describing the unidirectional extraction efficiency to bone mineral was significantly greater at the humerus compared to the lumbar spine for both study groups. No significant differences between skeletal sites were observed for k(3) or k(4). In conclusion a significant skeletal heterogeneity was observed in terms of bone perfusion and turnover between the lumbar spine and humerus. (18)F-PET may aid in our understanding of the importance of bone perfusion in osteoporosis and differences in regional bone turnover with disease and in response to therapy.

Peripheral quantitative computed tomography is useful to monitor response to alendronate therapy in postmenopausal women

A forearm fracture (Colles' fracture) is often the first sign of osteoporosis and may suggest underlying skeletal fragility. Therefore, establishment of a more accurate and reliable method for the measurement of bone mineral density (BMD) at the distal radius would be beneficial for patients who suffer from osteoporosis. The objective of this study was to evaluate the usefulness of peripheral quantitative computed tomography (pQCT) to monitor the response to alendronate therapy at the distal radius in early postmenopausal Japanese women. Thirty-two early postmenopausal women who were diagnosed with osteoporosis or osteopenia were randomized to either alendronate or control treatment. We analyzed the BMD of the distal radius by pQCT, lumbar spine by dual-energy X-ray absorptiometry (DXA) and the biochemical markers of bone turnover (deoxypyridinoline) at baseline, 3, 6 and 12 months. The control group showed a significant decrease from baseline in the trabecular BMD of the radius at 12 months (3.5 +/- 3.7%; p < 0.01), whereas the alendronate group showed a significant increase (4.3 +/- 8.1%). The changes in the trabecular BMD of the radius between the alendronate and control groups were statistically different at 6 and 12 months (p < 0.01). However, in the total BMD at the diaphysis of the radius, no significant differences were seen in the changes in bone densities between the alendronate and control groups after 1 year of treatment. pQCT detected significant differences in BMD of the radius in early postmenopausal women after 1 year of treatment with alendronate. Collectively, our preliminary clinical trial showed that pQCT might be useful to monitor response to alendronate therapy, especially at the radius, and it might explain why alendronate prevents Colles' fracture.

Magnetic field distribution in the presence of paramagnetic plates in magnetic resonance imaging: a combined numerical and experimental study

The amount and geometric distribution of paramagnetic components in tissue is considered as the basis of T2*-weighted magnetic resonance imaging (MRI). Such techniques are routinely applied for assessment of iron in parenchymal organs such as the liver (hemosiderosis). Furthermore, susceptibility sensitive MRI is discussed as an alternative method to x-ray techniques for quantitative assessment of paramagnetic spongy bone components in patients with osteoporosis. The presented work is dedicated to systematically examining the possible influences of macroscopic arrangements of paramagnetic plates on the magnetic field. In a theoretical approach magnetic field distribution was simulated applying decomposition of the plates in single dipoles. Plate size and distances between parallel plates, as well as plate orientation with respect to the static field, were varied for these numerical simulations. Experiments on corresponding plate arrangements were carried out on a 3 T whole body MR scanner using the field-sensitive MR sequence technique for B0 field mapping. Further examinations were carried out on a bone preparation of the femur, where T2* maps were measured and analyzed on a pixel-by-pixel basis at two orientations with respect to the static field. A series of experiments were performed using isotropic and anisotropic volume elements in three-dimensional gradient echo sequences. Resulting magnetic field distributions in the experimentally recorded B0 field maps were in good agreement with the numerical simulations. Field distortions dominated in areas close to the plates and especially near the edges. Those areas showed strong local field gradients, leading to pronounced signal dephasing effects. The examination of the bone preparations revealed different T2* values for identical regions in the bone when the orientation of the bone or the pixel geometry was changed with respect to the magnetic field. Those effects amounted to nearly 70% (22.9 ms versus 13.6 ms in a region of interest in the femur) for 90 degrees rotation of the femur in the magnetic fields. The orientation of anisotropic picture elements with constant size also showed a strong influence on the derived T2* value (up to 80%, increasing with anisotropy of picture elements).

A structural approach to the assessment of fracture risk in children and adolescents with chronic kidney disease

Children with chronic kidney disease (CKD) have multiple risk factors for impaired accretion of trabecular and cortical bone. CKD during childhood poses an immediate fracture risk and compromises adult bone mass, resulting in significantly greater skeletal fragility throughout life. High-turnover disease initially results in thickened trabeculae, with greater bone volume. As disease progresses, resorption cavities dissect trabeculae, connectivity degrades, and bone volume decreases. Increased bone turnover also results in increased cortical porosity and decreased cortical thickness. Dual-energy X-ray absorptiometry (DXA)-based measures of bone mineral density (BMD) are derived from the total bone mass within the projected bone area (g/cm(2)), concealing distinct disease effects in trabecular and cortical bone. In contrast, peripheral quantitative computed tomography (pQCT) estimates volumetric BMD (vBMD, g/cm(3)), distinguishes between cortical and trabecular bone, and provides accurate estimates of cortical dimensions. Recent data have confirmed that pQCT measures of cortical vBMD and thickness provide substantially greater fracture discrimination in adult dialysis patients compared with hip or spine DXA. The following review considers the structural effects of renal osteodystrophy as it relates to fracture risk and the potential advantages and disadvantages of DXA and alternative measures of bone density, geometry, and microarchitecture, such as pQCT, micro-CT (microCT), and micro magnetic resonance imaging (microMRI) for fracture risk assessment.

Age-related decline in trabecular and cortical density: a 5-year peripheral quantitative computed tomography follow-up study of pre- and postmenopausal women

This 5-year prospective study assessed changes in trabecular and cortical volumetric bone density at the non-weight-bearing radius and weight-bearing tibia among clinically healthy pre- and postmenopausal women. Altogether 79 premenopausal (mean age +/- SD at baseline 33 +/- 2 years) and 108 postmenopausal (68 +/- 2 years) women participated in the baseline and follow-up measurements. Trabecular density (TrD) of the distal radius and tibia and cortical density (CoD) of the radial and tibial shafts were assessed by peripheral quantitative computed tomography (pQCT). Repeated measures analysis of variance was used to analyze differences of means and mean changes between the age groups. As expected, TrD and CoD values were greater among premenopausal than postmenopausal women. Changes in radial TrD were similar in both age groups: mean (95% confidence interval) TrD of the distal radius declined by 3.0 mg/cm(3) (-0.9 to 7.0) and 5.1 mg/cm(3) (1.8-8.5) in the younger and older age groups, respectively. The respective declines in TrD of the distal tibia were 4.1 mg/cm(3) (2.1-6.0) and 2.8 mg/cm(3) (1.2-4.3). Decline in CoD was greater in the older than younger age group at both the radial and tibial shafts (P < 0.001). The mean absolute declines in radial CoD were 33.3 mg/cm(3) (27.9-38.7) and 49.4 mg/cm(3) (44.9-53.9) in younger and older women, and the declines in tibial CoD were 16.5 mg/cm(3) (12.6-20.2) and 28.1 mg/cm(3) (25.0-31.2), respectively. In conclusion, volumetric TrD in the weight-bearing tibia and non-weight-bearing radius showed similar age-related declines among pre- and postmenopausal women, while the decline in CoD was greater among postmenopausal women.

Effect of early menopause on bone mineral density and fractures

OBJECTIVE

To review the data on the effect of early menopause on bone. Do women undergoing early menopause develop lower bone mineral density at an earlier age and do they have a higher incidence of osteoporotic fractures? Is there a difference on bone between women who undergo early natural menopause compared to women who have early menopause after oophorectomy?

RESULTS

The earlier in life that menopause occurs, the lower the bone density will be later in life. Low bone density is associated with a higher fracture rate, and several studies show a relationship between early menopause, oophorectomy, and an increase in osteoporotic fractures.

CONCLUSIONS

Early menopause is a risk factor for osteoporosis. Women with an early menopause should have bone density testing performed within 10 years of menopause so that osteopenia or osteoporosis will be diagnosed early and appropriate anti-resorptive therapy initiated.

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.

Annual change in bone mineral density in predialysis patients with chronic renal failure: significance of a decrease in serum 1,25-dihydroxy-vitamin D

Bone disease occurs in the predialysis phase of chronic renal failure (CRF). The aim of this study was to examine how a decrease in renal function affects annual bone mineral density (BMD) changes in predialysis CRF patients and to examine the factors that affect BMD. The BMD of the distal radius in 53 predialysis CRF patients (age, 61.3 +/- 10.8 years; serum creatinine 2.7 +/- 1.2 mg/dl) was measured by peripheral quantitative computed tomography (pQCT) twice with a 1-year interval. The total BMD of the radius significantly decreased over a year (P < 0.001), and both trabecular and cortical BMD showed a significant decrease. Significant positive correlations with BMD changes were found for estimated creatinine clearance (r = 0.375, P < 0.01) and baseline serum 1,25(OH)(2)D (r = 0.434, P < 0.005), indicating that BMD decreased to a greater extent with larger reductions in creatinine clearance and serum 1,25(OH)(2)D. Of several bone metabolic markers examined, baseline serum osteocalcin was significantly positively correlated with annual BMD changes (r = -0.276, P < 0.05). Multiple regression analysis showed that baseline serum 1,25(OH)(2)D (beta = 0.434) was a significant predictor of decreases in total and trabecular BMD (R (2) = 0.188, P < 0.01; and R (2) = 0.207, P < 0.01), independent of other confounding factors. These results indicate that BMD decreases as renal function deteriorates in predialysis CRF patients, and that osteocalcin is a clinically useful marker associated with the decrease in BMD. The serum 1,25(OH)(2)D level is the principal factor affecting BMD of the radius, suggesting that supplementation with an active form of vitamin D is of importance for predialysis CRF patients.

Peripheral quantitative computed tomography (pQCT) is useful for monitoring bone mineral density of the patients who receive hormone replacement therapy

OBJECTIVE

A forearm fracture (Colles' fracture) is often the first sign of osteoporosis and should alert the patient and physician to the possibility of underlying skeletal fragility. Therefore, the establishment of a more accurate and reliable method for the measurement of bone mineral density (BMD) at the distal radius would be beneficial for the patients who suffer from osteoporosis. The objective of the present study was to evaluate the usefulness of peripheral quantitative computed tomography (pQCT) to assess the change of BMD at the distal radius in early postmenopausal women who receive hormone replacement therapy (HRT).

METHODS

Twenty healthy early postmenopausal women who were diagnosed as osteoporosis or osteopenia were randomized to either HRT or placebo treatment. We analyzed BMD of the distal radius by pQCT, lumbar spine by dual-energy X-ray absorptiometry (DXA) and the biochemical markers of bone turn over (osteocalcin, deoxypyridinoline) every 6 months.

RESULTS

The placebo group showed a significant decrease from the baseline in the trabecular BMD of the radius at 12 months (7.4+/-2.5%) (p<0.05), whereas the HRT group showed a slight increase (0.7+/-2.2%). The changes in the trabecular BMD of the radius between the HRT and placebo groups were statistically different at 12 months (p<0.05). On the other hand, in the cortical BMD of the radius, no significant differences were seen between the changes of bone densities in the HRT and control groups after 1 year of treatment. pQCT could detect a significant loss of BMD of the radius in early postmenopausal women after 1 year and HRT prevented its loss.

CONCLUSION

Our preliminary clinical trial showed that pQCT might be useful for the early detection of bone loss in early postmenopausal women and for the monitoring BMD of the patients who receive HRT.

Effect of primary hyperparathyroidism on volumetric bone mineral density and bone geometry assessed by peripheral quantitative computed tomography in postmenopausal women

CONTEXT

Primary hyperparathyroidism (PH) is characterized by inappropriate PTH elevation with or without hypercalcemia. Bone disease involves catabolic action at cortical sites, whereas cancellous sites and geometry might be relatively preserved.

OBJECTIVE

Our objective was to examine the effect of PH on quantitative and qualitative bone characteristics using peripheral quantitative computed tomography at the tibia in postmenopausal women with PH and healthy controls.

DESIGN AND SETTING

We conducted a cross-sectional study at a tertiary referral center.

PATIENTS

Fifty-two postmenopausal women with PH and 56 healthy controls, comparable for age and anthropometric measures, participated.

INTERVENTION

There was no intervention.

MAIN OUTCOME MEASURE

We assessed volumetric bone mineral density (vBMD), bone mineral content (BMC), cortical thickness, cortical and trabecular area, peri- and endosteal circumference, and polar stress strength index assessed by peripheral quantitative computed tomography of the left tibia at 4% (cancellous), 14% (transition zone), and 38% (cortical) from the distal end.

RESULTS

At 4%, there was a significant decrease of trabecular BMC and vBMD (P < 0.001), effect particularly evident in hypercalcemic patients, whereas trabecular area was comparable. At 38%, cortical BMC (P < 0.01), vBMD (P < 0.01), area (P < 0.05), and thickness (P < 0.001) were reduced in the PH group, particularly in hypercalcemic patients. Endosteal circumference increased (P < 0.001), whereas periosteal circumference was comparable, indicating cancellization of cortical bone. At 14%, polar stress strength index was significantly decreased (P < 0.01) in hypercalcemic patients, indicating impairment of bone mechanical properties.

CONCLUSIONS

Normocalcemic PH is characterized by catabolic actions at both cortical and cancellous sites (38 and 4%, respectively), an effect accentuated in hypercalcemic patients. Cortical geometric properties are adversely affected even in normocalcemic patients, whereas trabecular properties are generally preserved.

Cortical pQCT measures are associated with fractures in dialysis patients

To determine if pQCT could identify HD patients with fractures, we conducted a cross-sectional study in 52 men and women on HD. We found that cortical, but not trabecular, pQCT measures were associated with fractures.

INTRODUCTION

Fractures are common in hemodialysis (HD) patients, yet DXA is inconsistently associated with fractures. One explanation for this lack of association may be that HD patients have a selective decrease in cortical density not identified by standard DXA.

MATERIALS AND METHODS

We used pQCT to examine cross-sectional associations between cortical and trabecular measures and fractures in 36 men and 16 women, > or = 50 years of age, on HD for at least 1 year. We confirmed low-trauma nonspine fractures since starting HD. Prevalent vertebral fractures were identified by morphometry of lateral spine X-rays. pQCT measurements of the nondominant radius included trabecular density, cortical density, total area, cortical area, and cortical thickness. We also obtained DXA measurements of the hip and lumbar spine. We used logistic regression models, adjusted for age, weight, and sex, to examine the association between fracture (vertebral and/or self-reported nonspine) and each pQCT measure. Results are reported as ORs per SD decrease in the independent variable.

RESULTS

The mean age was 65.8 +/- 9.0 (SD) years, the mean weight was 72.3 +/- 15.6 kg, most (32 of 52) subjects were white, and there were 32 fractures in 27 subjects (prevalent vertebral fracture or low-trauma fracture) since starting dialysis. A decrease in cortical density was associated with fractures (OR = 16.67; 95% CI: 2.94-83.33), as was a decrease in cortical area (OR = 3.04; 95% CI: 1.28-7.25) and a decrease in cortical thickness (OR = 3.26; 95% CI: 1.36-7.87). Fractures were not associated with pQCT trabecular density (OR = 1.18; 95% CI: 0.6-2.33), total area (OR = 1.1; 95% CI: 0.59-1.7), or DXA measurements of the hip and spine.

CONCLUSIONS

Cortical parameters of the radius were associated with fractures in HD patients. If confirmed in prospective studies, these findings may explain the lack of association between fracture and standard DXA measurements and raise the possibility that pQCT could be used to identify HD patients at high risk of fracture.

A densitometric and morphometric analysis of the skeleton in adults with varying degrees of growth hormone deficiency

CONTEXT

Low bone mass is a characteristic feature of the adult GH deficiency (GHD) syndrome, but recent dual-energy x-ray absorptiometry (DXA) studies in patients with GH-receptor and GHRH-receptor gene mutations suggest that the situation is more complex.

OBJECTIVE

The objective was to define bone areal and volumetric densities and morphometry in hypopituitary adults.

DESIGN

The study was a cross-sectional case-controlled study performed between 1999 and 2001.

SETTING

The study was undertaken at an endocrine tertiary referral center.

PATIENTS

Thirty patients with GHD, 24 with GH insufficiency (GHI) [peak GH, 3-7 microg/liter (9-21 mU/liter)], and 30 age- and sex-matched controls were included for study.

MAIN OUTCOME MEASURES

DXA and peripheral quantitative computed tomography (pQCT) derived bone density and morphometry were measured.

RESULTS

No densitometric or morphometric abnormalities were detected in GHD patients who acquired their deficiency during adult life. GHD adults of childhood-onset (CO-GHD) showed decreased bone mineral density at the lumbar spine and hip on DXA. pQCT of the radius showed that CO-GHD patients have normal trabecular bone mineral density and only a 2% decrease in cortical density. Radial bone area was reduced 14.5%, cortical thickness 20%, and cortical cross-sectional area 23%, culminating in a reduction in cortical bone of 25%. The "apparent" low DXA bone density in CO-GHD adults therefore relates primarily to reduced cortical thickness and smaller bone area. DXA and pQCT data derived from adults with GHI revealed no evidence of densitometric or morphometric abnormalities.

CONCLUSIONS

1) Adult-onset GHD patients have normal bone density and size. 2) CO-GHD adults have marginally reduced cortical density but significantly reduced cortical bone as a result of reduced cortical thickness and bone size. 3) GHI has no measurable impact on the skeleton.

Evaluation of bone mineral density of the lumbar spine in patients with beta-thalassemia major with dual-energy x-ray absorptiometry and quantitative computed tomography: a comparison study

Osteoporosis is a common, multifactorial cause of morbidity in patients with beta-thalassemia. The present study was performed to compare bone mineral density (BMD) results in the lumbar spine of thalassemic patients measured by both dual-energy x-ray absorptiometry (DEXA) and quantitative computed tomography (QCT), and to determine their correlations with the markers of bone turnover. BMD was measured in the lumbar spine of 13 regularly transfused patients with beta-thalassemia major by both DEXA and QCT. Blood and urine samples were obtained for the determination of biochemical and hormonal profiles. Both T-scores and Z-scores were higher when measured by QCT (T-score = -0.41 +/- 1.31, Z-score = -0.56 +/- 1.08, mean +/- SD) compared with the values given by DEXA (T-score = -2.57 +/- 0.88, Z-score = -2.32 +/- 1.11, P = 0.0005). In comparison to DEXA, QCT T-scores were more closely correlated with age (r = -0.19 vs. r = -0.70, P = 0.0068). Strong negative correlation was found between QCT values and age (r = -0.67, P = 0.01). In comparison to DEXA T-scores, QCT T-scores were more closely correlated with osteocalcin, urine N-telopeptide cross-links of type I collagen, and deoxypyridinoline, but without statistical significance. DEXA T-scores were better correlated only with urine C-terminal telopeptides of type I collagen, but again without statistical significance. These results imply that the two methods cannot be used interchangeably in assessing BMD in thalassemic patients. However, which one of these two techniques more precisely determines the overall strength of vertebrae in patients with beta-thalassemia remains to be investigated.

Bone status in primary hyperparathyroidism assessed by regional bone mineral density from the whole body scan and QUS imaging at calcaneus

To assess the bone mineral density status in primary hyperparathyroidism (PHPT), we studied 64 females with PHPT and 17 healthy women. Regional BMD (arms, trunk, legs) from the whole body scan and conventional sites (lumbar spine, femur, radius) were assessed by DXA. Quantitative ultrasound (QUS) imaging measurements were performed at calcaneus. Sixteen women had history of renal lithiasis, 11 had low impact fracture and 37 women had neither renal lithiasis nor fracture. In the entire group, the mean Z-scores were significantly decreased at all sites (lumbar spine, femur, radius). In all clinical subgroups, the mean Z-scores were significantly decreased at radius. The mean Z-scores in premenopausal women were significantly decreased comparatively to postmenopausal women at lumbar spine and femur. In a group of PHPT females matched to controls for age and BMI, only BMD values at radius were lower in PHPT patients than in control (P < 0.03). However, from the whole body scan data, all sites but no trunk were significantly involved in PHPT patients (P < 0.04). Using QUS measurements at calcaneus, the BUA but not SOS in PHPT females was significantly lower (P = 0.03) than in controls. Our results suggest that low BMD at lumbar spine and femur is encountered preferentially in premenopausal women. The BMD decrease predominates at limbs in PHPT with presumably a gradient from proximal to distal part of the limbs. Indeed, the distal part of the limbs are the most affected areas in PHPT whatever the amount of cortical or trabecular bone.

Effects of sex and age on bone microstructure at the ultradistal radius: a population-based noninvasive in vivo assessment

In a population-based cross-sectional study, we examined effects of sex and age on bone microstructure at the wrist using high-resolution 3-D pQCT. Compared with women, men had thicker trabeculae in young adulthood and had less microstructural damage with aging. These findings may contribute to the virtual immunity of men to age-related increases in wrist fractures.

INTRODUCTION

Although changes in bone microstructure contribute to fracture risk independently of BMD, it has not heretofore been possible to assess this noninvasively in population-based studies.

MATERIALS AND METHODS

We used high-resolution 3-D pQCT imaging (voxel size, 89 mum) to define, in a random sample of women (n = 324) and men (n = 278) 21-97 years of age, sex and age effects on bone microstructure at the wrist.

RESULTS

Relative to young women (age, 20-29 years), young men had greater trabecular bone volume/tissue volume (BV/TV; by 26%, p = 0.001) and trabecular thickness (TbTh; by 28%, p < 0.001) but similar values for trabecular number (TbN) and trabecular separation (TbSp). Between ages 20 and 90 years, cross-sectional decreases in BV/TV were similar in women (-27%) and in men (-26%), but whereas women had significant decreases in TbN (-13%) and increases in TbSp (+24%), these parameters had little net change over life in men (+7% and -2% for TbN and TbSp, respectively; p < 0.001 versus women). However, TbTh decreased to a greater extent in men (-24%) than in women (-18%; p = 0.010 versus men).

CONCLUSIONS

Whereas decreases with age in trabecular BV/TV are similar in men and women, the structural basis for the decrease in trabecular volume is quite different between the sexes. Thus, over life, women undergo loss of trabeculae with an increase in TbSp, whereas men begin young adult life with thicker trabeculae and primarily sustain trabecular thinning with no net change in TbN or TbSp. Because decreases in TbN have been shown to have a much greater impact on bone strength compared with decreases in TbTh, these findings may help explain the lower life-long risk of fractures in men, and specifically, their virtual immunity to age-related increases in distal forearm fractures.

Long-term recreational gymnastics provides a clear benefit in age-related functional decline and bone loss. A prospective 6-year study

INTRODUCTION

Bone fragility and decreased functional performance are risk factors for osteoporotic fractures. The influence of long-term recreational gymnastics on the maintenance of bone rigidity and physical performance was evaluated.

METHODS

One hundred and seven gymnasts and 110 referents (93% of the original sample) participated in this 6-year prospective study. Analysis of covariance (ANCOVA) was used to estimate the between-group differences and changes by time, and regression analyses to find predictors for changes.

RESULTS

In both groups agility and leg extensor power decreased by over 3% and 10%, respectively, but the original between-group differences, favoring the gymnasts, persisted. Proximal femur bone mineral content (BMC) decreased approximately 0.5% per year in both groups, and femoral neck section modulus decreased. Trabecular density of the distal tibia declined only marginally, and cortical area of the tibial midshaft remained unchanged, while cortical density decreased about 2% in both groups. After adjustment by age, height, weight, change in weight, and follow-up time, antiresorptive medication and high calcium intake accounted most for the maintenance of bone rigidity.

CONCLUSIONS

In spite of similar rates of decline in bone characteristics and physical performance, the recreational gymnasts' overall physical condition was comparable to the level that their less active referents had shown approximately 5 years earlier.

Effects of age, grip strength and smoking on forearm volumetric bone mineral density and bone geometry by peripheral quantitative computed tomography: comparisons between female and male

Peripheral quantitative computed tomography (pQCT) is useful to measure volumetric bone mineral density (vBMD) distinguishing trabecular from cortical bones as well as quantity of bone geometry. In the present study, we examined the effects of age, grip strength and smoking on vBMD, bone geometry and bone strength index (polar strength strain index (SSIp)), and then compared with the differences between female and male by employing pQCT in Japanese 252 female and 230 male subjects. Age was negatively correlated with vBMD, cortical area (Ct.Ar) and cortical thickness (Ct.Th) as well as SSIp in both sexes, and the correlation coefficients were higher in female, compared with those in male. Although age was correlated with endocortical circumferences (En.Le) in both sexes, periosteal circumferences (Ex.Le) were correlated with age only in male. Volumetric BMD, Ct.Ar, Ct.Th and SSIp were significantly lower in the group with vertebral fractures, although En.Le and Ex.Le were similar between subjects with and without vertebral fractures. Grip strength was positively correlated with vBMD, Ct.Ar, Ct.Th as well as SSIp. The extent of correlation was much higher in female, compared with that in male. Ct.vBMD, Ct.Ar, Ct.Th and SSIp, but not trabecular vBMD, were significantly lower in the group with high Brinkman index (number of cigarettes smoked per day) x (duration of smoking (years)) in female. These parameters were not significantly different between groups with high and low Brinkman index in male. In conclusion, the present study demonstrated that age, grip strength and smoking affected forearm vBMD, bone geometry and bone strength index by pQCT. These effects were greater in female, compared with those in male.

Assessment of bone mass following renal transplantation in children

Throughout childhood and adolescence, skeletal growth results in site-specific increases in trabecular and cortical dimensions and density. Childhood osteoporosis can be defined as a skeletal disorder characterized by compromised bone strength predisposing to an increased risk of fracture. Pediatric renal transplant recipients have multiple risk factors for impaired bone density and bone strength, including pre-existing renal osteodystrophy, delayed growth and development, malnutrition, decreased weight-bearing activity, inflammation, and immunosuppressive therapies. Dual energy X-ray absorptiometry (DXA) is the most-common method for the assessment of skeletal status in children and adults. However, DXA has many important limitations that are unique to the assessment of bone health in children. Furthermore, DXA is limited in its ability to distinguish between the distinct, and sometimes opposing, effects of renal disease on cortical and trabecular bone. This review summarizes these limitations and the difficulties in assessing and interpreting bone measures in pediatric transplantation are highlighted in a review of select studies. Alternative strategies are presented for clinical and research applications.

The clinical significance of serum osteocalcin and N-terminal propeptide of type I collagen in predialysis patients with chronic renal failure

Several new serum markers for bone metabolism have recently become available and are being applied to clinical practice. Their clinical usefulness in predialysis patients with chronic renal failure (CRF), however, has not yet been determined. Serum levels of three bone formation markers-bone alkaline phosphatase (BAP), osteocalcin (OC), and N-terminal propeptide of type I collagen (PINP)-and three bone resorption markers-type I collagen cross-linked N-telopeptide (NTx), deoxypyridinoline (DPD), and pyridinoline (PYD)-were measured simultaneously in 85 predialysis CRF patients (serum creatinine 3.5 +/- 1.9 mg/dl, 61.0 +/- 10.9 years old, 54 males and 31 females, 36 diabetics and 49 nondiabetics) to examine the relationships between these markers and bone mineral density (BMD) of the distal radius, as measured by peripheral quantitative computed tomography (pQCT). Trabecular BMD, which is strongly affected by bone metabolism, was significantly negatively correlated with each of the bone formation markers (r=-0.341, p=0.0016, for OC; r=-0.314, p=0.0036, for PINP; r=-0.238, p=0.0315, for BAP), but there was no significant correlation between BMD and any of the bone resorption markers. In multivariate regression analyses (adjusted by age, sex, presence of diabetes, glomerular filtration rate, intact parathyroid hormone, calcium, phosphate, and 1,25-dihydroxyvitamin D), OC and PINP were significantly associated with a decrease in BMD, but BAP was not. In conclusion, we demonstrated that in predialysis CRF patients, BMD of the distal radius, particularly of trabecular bone, is associated with serum OC and PINP levels. OC and PINP are suggested to be possible parameters for the clinical evaluation of the effect of bone metabolism on BMD.

Simulated influence of osteoporosis and disc degeneration on the load transfer in a lumbar functional spinal unit

As life expectancy increases, age-related disorders and the search for related medical care will expand. Osteoporosis is the most frequent skeletal disease in this context with the highest fracture risk existing for vertebrae. The aging process is accompanied by systemic changes, with the earliest degeneration occurring in the intervertebral discs. The influence of various degrees of disc degeneration on the load transfer was examined using the finite element method. The effect of different possible alterations of the bone quality due to osteoporosis was simulated by adjusting the corresponding material properties and their distribution and several loadings were applied. An alteration of the load transfer, characterised by changed compression stiffness and strain distributions as well as magnitudes, due to osteoporotic bone and degenerated discs was found. When osteoporosis was simulated, the stiffness was substantially decreased, larger areas of the cancellous bone were subjected to higher strains and strain maxima were increased. Increasing ratios of transverse isotropy in the osteoporotic bone yielded smaller effects than reduced bone properties. Including a degenerated disc mainly altered the strain distribution. Combining osteoporosis and degenerated discs reduced the areas of cancellous bone subjected to substantial strain. Based on these results, it can be concluded that the definition of a healthy disc in osteoporotic spines might be considered as a worst-case scenario. One attempt to evaluate the progress of osteoporosis can be made by introducing increasing degrees of anisotropy. If several parameters in a model are changed to simulate degeneration, it should be pointed out how each individual definition influences the overall result.

Relationship between the duration of paralysis and bone structure: a pQCT study of spinal cord injured individuals

The aim of the present study was to describe bone loss of the separate compartments of trabecular and cortical bone, as well as changes in bone geometry of a large number of spinal cord injured (SCI) individuals. Eighty-nine motor complete spinal cord injured men (24 tetraplegics and 65 paraplegics) with a duration of paralysis of between 2 months and 50 years were included in the study. Distal epiphyses and midshafts of the femur, tibia, and radius were measured by peripheral quantitative computed tomography. The same measurements were performed in a reference group of 21 healthy able-bodied men of the same age range. In the femur and tibia, bone mass, total and trabecular bone mineral density (BMDtot and BMDtrab, respectively) of the epiphyses, as well as bone mass and cortical cross-sectional area of the diaphyses, showed an exponential decrease with time after injury in the spinal cord injured subjects. The decreasing bone parameters reached new steady states after 3-8 years, depending on the parameter. Bone mass loss in the epiphyses was approximately 50% in the femur and 60% in the tibia, while the shafts lost only approximately 35% in the femur and 25% in the tibia. In the epiphyses, bone mass was lost by reducing BMD, while in the shaft bone mass was lost by reducing cortical wall thickness, a process achieved by endosteal resorption advancing at a rate of about 0.25 mm/year within the first 5-7 years after injury. Except for a slight transient decrease in cortical BMD of the femoral and tibial shaft during the first 5 years after the spinal cord lesion, cortical BMD of the spinal cord injured subjects was found to be at reference values. Bone parameters of the radial epiphysis in paraplegic subjects showed no deficits compared to the reference group. Furthermore, a trend for an increased radial shaft diameter suggests periosteal apposition as a consequence of increased loading of the arms.

Assessing bone mineral density in vivo: quantitative computed tomography

Egg-laying hens require substantial amounts of Ca to support eggshell formation. Over time, structural bone is catabolized to provide some of the Ca required; the structural bone is not replaced. As the hen ages, this can eventually lead to osteoporosis. Quantitative Computed Tomography (QCT) is a nondestructive technique used to measure bone mineral density (BMD). QCT is used diagnostically in humans to assess osteoporosis; BMD determined by QCT is correlated with other, more invasive methods of bone mineral determinations, such as ashing. An x-ray is sent through a bone at multiple angles within a plane to generate a 2-dimensional image and a 3-dimensional calculation of volume and BMD. The technique allows resolution of total, trabecular, and cortical BMD and cross-sectional areas. The separation of bone types allows very precise measurements of the bone compartments most important in Ca supply for eggshell formation and bone strength. QCT has been adapted in our laboratory to measure BMD in vivo and ex vivo in poultry; values obtained for poultry bones are moderately correlated with destructive means of assessing bone quality such as breaking strength, ashing, and chemical bone mineral determinations. Thus, changes in BMD of individual birds can be measured over time; BMD at specific time points can be correlated with production parameters and eggshell quality traits. QCT is an effective technique to measure BMD in laying hens, which allows resolution of total BMD as well as cortical and trabecular BMD.

Comparison of incadronate and alfacalcidol on increased bone turnover caused by ovariectomy in rats

Mineral density of trabecular bone at the metaphyses of right tibiae was measured by peripheral quantitative computed tomography (pQCT) in ovariectomized rats. Bone mineral density (BMD) decreased dramatically in the 4 weeks following ovariectomy, suggesting that the method is sensitive enough to detect decreased bone mineral density within a short period. Orally administered incadronate dose dependently inhibited the decrease in trabecular bone mineral density induced by ovariectomy, as assessed 4 weeks after surgery. Significant inhibition was observed at doses of more than 0.3 mg/kg/day. Moreover, incadronate at doses of 1 mg/kg or more inhibited the increase in urinary deoxypyridinoline levels induced by ovariectomy, and although slightly increased serum intact parathyroid hormone (PTH) levels were observed, no significant alteration in serum calcium ion levels or urinary calcium excretion occurred. In contrast, while alfacalcidol inhibited the decrease in bone mineral density and the increase in urinary deoxypyridinoline levels at a dose of 300 ng/kg, it significantly lowered serum intact PTH levels and elevated serum free calcium levels as well as urinary calcium excretion. These results suggest that incadronate exerts its pharmacological effect (inhibition of bone resorption and increase in bone mass) by a mechanism different from that of alfacacidol.

Separate assessment of forearm cortical and trabecular bone density from standard densitometry data

BACKGROUND

Cortical and trabecular bone are different bone components. Their mineral density cannot be measured directly by areal bone densitometry.

AIM

To introduce a method for assessment of pure radial cortical and trabecular bone density based on standard densitometry data.

METHOD

The study included 418 healthy females (aged 20-83 years, body mass index between 19 and 30) free of previous fractures and conditions or drugs affecting bone metabolism; as well as a group of 64 age-matched females with early menopause. Forearm bone density was measured by single X-ray absorptiometry and calculated separately for cortical and trabecular bone. Age-adjusted bone density curves were built.

RESULTS

Peak bone density was found to occur between 30 and 34 years of age and was 0.561 g/cm2 for cortical and 0.281 g/cm2 for trabecular bone. In comparison, lowest values were registered between 70 and 74 years of age; cortical bone density reduced by 26% and trabecular density by 44%. Both bone density profiles through life reflected the earlier peri- and postmenopausal (mainly trabecular) and later senile (cortical bone also involved) changes in bone mass. A step-wise pattern of trabecular bone reduction was registered with acceleration around 45, 55 and 65 years. The effects of early menopause on trabecular and cortical bone were tested in the prematurely menopausal women.

CONCLUSIONS

The ability of our model to discriminate between natural and premature menopause was moderate. Although hypothetical (based on calculations from integral densitometry data rather than on direct measurements), our method could differentiate between cortical and trabecular osteopenia and may prove helpful in assessing the type of osteoporosis, in making therapy choices and monitoring response to therapy based on forearm bone density.