Normal ranges for bone loss rates

Alendronate/Vitamin D for attenuating bone mineral density loss during antiretroviral initiation: a pilot randomized controlled trial

Background: Antiretroviral therapy (ART) initiation is associated with decreases in bone mineral density (BMD).Objectives: To plan for a larger trial, we sought to obtain preliminary estimates for the difference in the change in BMD at 48 weeks achieved with 24 weeks of prophylactic alendronate/vitamin D during ART initiation compared to no intervention, the within-group standard deviation of this change, and intra-patient correlation coefficient for repeated BMDs. Secondary objectives included assessing enrollment feasibility, treatment acceptability, adherence and safety.Methods: We randomized treatment-naïve HIV-positive adults initiating tenofovir disoproxil fumarate/emtricitabine/elvitegravir/cobicistat or abacavir/lamivudine/dolutegravir 1:1:1 to immediate alendronate/vitamin D3 70 mg/5600 IU for 24 weeks (concomitant treatment arm, CTA), the same intervention starting 24 weeks after study entry (delayed treatment arm, DTA), or no bone anti-resorptive therapy (standard of care, SOC). We assessed BMD, acceptability, adverse events and drug adherence at baseline, week 24 and week 48.Results: Of 29 included participants, 72% initiated TDF/FTC/ELV/c and 28% initiated ABC/3TC/DTG. Median (IQR) CD4 count was 388 (303,525) cells/mm³ and median plasma HIV RNA was 4.45 (2.26, 4.84) log₁₀ copies/mL. The mean (SD) percentage change in BMD for the CTA and DTA combined was 1.95% (2.53%), 0.38% (3.34%), and -0.57% (3.50%) at the lumbar spine, femoral neck and total hip respectively at 48 weeks. The ICC among repeated measurements of BMD was 0.978, 0.964, and 0.967 at these sites, respectively. Enrollment feasibility, drug acceptability, adherence, and tolerability were good.Conclusions: Our findings inform the sample size for a larger trial of bone anti-resorptive therapy during ART initiation and support feasibility.

Intrinsic material property differences in bone tissue from patients suffering low-trauma osteoporotic fractures, compared to matched non-fracturing women

Osteoporotic (low-trauma) fractures are a significant public health problem. Over 50% of women over 50yrs. of age will suffer an osteoporotic fracture in their remaining lifetimes. While current therapies reduce skeletal fracture risk by maintaining or increasing bone density, additional information is needed that includes the intrinsic material strength properties of bone tissue to help develop better treatments, since measurements of bone density account for no more than ~50% of fracture risk. The hypothesis tested here is that postmenopausal women who have sustained osteoporotic fractures have reduced bone quality, as indicated with measures of intrinsic material properties compared to those who have not fractured. Transiliac biopsies (N=120) were collected from fracturing (N=60, Cases) and non-fracturing postmenopausal women (N=60, age- and BMD-matched Controls) to measure intrinsic material properties using the nano-indentation technique. Each biopsy specimen was embedded in epoxy resin and then ground, polished and used for the nano-indentation testing. After calibration, multiple indentations were made using quasi-static (hardness, modulus) and dynamic (storage and loss moduli) testing protocols. Multiple indentations allowed the median and variance to be computed for each type of measurement for each specimen. Cases were found to have significantly lower median values for cortical hardness and indentation modulus. In addition, cases showed significantly less within-specimen variability in cortical modulus, cortical hardness, cortical storage modulus and trabecular hardness, and more within-specimen variability in trabecular loss modulus. Multivariate modeling indicated the presence of significant independent mechanical effects of cortical loss modulus, along with variability of cortical storage modulus, cortical loss modulus, and trabecular hardness. These results suggest mechanical heterogeneity of bone tissue may contribute to fracture resistance. Although the magnitudes of differences in the intrinsic properties were not overwhelming, this is the first comprehensive study to investigate, and compare the intrinsic properties of bone tissue in fracturing and non-fracturing postmenopausal women.

Changes in metacarpal bone mineral density with age and menopause using computed X-ray densitometry in Japanese women: Cross-sectional and longitudinal study

BACKGROUND

Bone mineral density (BMD) loss with age and menopause is widely accepted in elderly women. However, only a few studies have utilized a multiple regression model that includes physical characteristics to assess comprehensive lifetime changes in BMD.

OBJECTIVE

A prospective study was conducted to characterize the normal patterns in metacarpal BMD changes in Japanese women, and to assess the applicability of a fitting model using cross-sectional data compared with longitudinal variability.

SUBJECTS AND METHODS

The study consisted of 5422 healthy women in cross-sectional data and a 1-year follow-up of 359 women. The metacarpal BMD was measured by computed X-ray densitometry. Multiple linear and nonlinear regression analyses were performed in cross-sectional subjects. Nonparametric analysis was used to compare percentage rates of BMD changes between actual and estimated values.

RESULTS

The cross-sectional data showed that the best-fit equation was a nonlinear change model using the variables of age and height in premenopausal women, and years since menopause (YSM), age and height in postmenopausal women. The results of longitudinal data indicated the following. In premenopausal women, the actual BMD changes were greater in the 30-39 age group than the 20-29 age group and were less in the 50-59 group than the 40-49 group. The rates of annual change in BMD between the actual value and estimated value by change model were very similar. In postmenopausal women, the actual changes in BMD indicated that the rapid rate of reduction observed was over 3% at 0-5 YSM and 1.5% at 6-10 YSM, and thereafter showed a slower rate of decline at 11 YSM. The change model represented the trend of actual change in BMD for postmenopausal women, whereas the rates of estimated BMD loss underestimated the actual changes at 1-10 YSM.

CONCLUSION

The change model for premenopausal women using cross-sectional data is beneficial in evaluating the actual metacarpal BMD variability, whereas that for postmenopausal women is insufficient in estimating the longitudinal BMD variability.

Risk factors for vertebral and nonvertebral fracture over 10 years: a population-based study in women

Risk factors may vary for different types of fracture, in particular for vertebral fractures. We followed 367 women >50 yr of age from a population-based cohort for up to 10 yr. Factors that predicted vertebral rather than nonvertebral fractures related to physical weakness, poor health, and weight loss. Similar factors were also associated with greater bone loss at the hip.

INTRODUCTION

Many risk factors predict fractures overall, but it is less clear whether certain factors relate to vertebral fractures in particular. The aim of this study was to compare the risk factors for vertebral and nonvertebral fractures.

MATERIALS AND METHODS

We carried out a 10-yr prospective population-based study of 375 women who were 50-85 yr of age initially. At baseline, we measured BMD, blood and urine biochemistry, and anthropometric measurements. Medical and lifestyle data were obtained by questionnaire. Incident vertebral fractures were determined for 311 subjects from spinal radiographs at 0, 2, 5, 7, and 10 yr using an algorithm-based qualitative method, and nonvertebral fractures were confirmed radiographically. Relative risks were calculated by Cox regression analysis.

RESULTS

During follow-up, 70 subjects sustained one or more nonvertebral fractures and 29 sustained one or more vertebral fractures. Risk factors that predicted both types of fracture included increasing age, decreasing BMD at all sites, prevalent vertebral fracture, and shorter estrogen exposure. For nonvertebral fractures only, the risk factors included low urinary creatinine and less frequent use of stairs. The factors for vertebral fractures included lighter weight, reduced body fat, heavy smoking, lower serum calcium, albumin, and thyroid T(3), weak grip strength, and poor physical capability. In a multivariate model, weight, fat mass, serum calcium and T(3), prevalent vertebral fracture, and physical capability remained significant. Furthermore, grip strength, serum albumin, weight loss, and physical capability were associated with rate of bone loss at the femoral neck, and a fast rate of bone loss was also associated with vertebral fractures.

CONCLUSIONS

We conclude that overall frailty, which may consist of general poor health, small or thin body size, and lack of strength and physical capability, predicts vertebral fractures but is not a significant predictor of nonvertebral fractures. Bone loss rates are associated with similar risk factors and also with the incidence of vertebral fractures.

Longitudinal changes in forearm bone mineral density in women and men aged 45-84 years: the Tromso Study, a population-based study

The aim of this study was to describe changes in bone mineral density in Norwegian women and men aged 45-84 years in a population-based, longitudinal study. Bone mineral density (g/cm2) was measured at distal and ultradistal forearm sites with single x-ray absorptiometric devices in 3,169 women and 2,197 men at baseline in 1994-1995 and at follow-up in 2001 (standard deviation, 0.4 years). The mean annual bone loss was -0.5% and -0.4% in men and -0.9% and -0.8% in women not using hormone replacement therapy at the distal and ultradistal sites, respectively. In men, age was a negative predictor of bone mineral density change at both sites. Women not using hormone replacement therapy had the highest bone loss at the ultradistal site 1-5 years after menopause. The correlation between the two measurements was high: r = 0.93 and r = 0.90 in women and r = 0.96 and r = 0.93 in men for the distal and ultradistal sites, respectively. More than 70% kept their quartile positions, indicating a high degree of tracking of bone mineral density measurements. Although the study population live above the polar circle, the rate of bone loss was not higher at the distal and ultradistal forearm sites compared with that of other cohorts.

Adverse effects of antiepileptic drugs on bone structure: epidemiology, mechanisms and therapeutic implications

Antiepileptic drugs (AEDs) were first associated with disorders of bone in both adults and children in the late 1960s. The most severe manifestations of these disorders are osteopenia/osteoporosis, osteomalacia and fractures. Bone disease has been described in several groups of patients receiving AEDs. Groups identified as being more vulnerable to AED-associated bone disease include institutionalised patients, postmenopausal women, older men and children. Radiological and histological evidence of bone disease is found in patients taking AEDs. Numerous biochemical abnormalities of bone metabolism have also been described. The severity of bone and biochemical abnormalities is thought to correlate with the duration of AED exposure and the number of AEDs used. In monotherapy, the AEDs most commonly associated with altered bone metabolism are phenytoin, primidone and phenobarbital (phenobarbitone). To date there have been no reports of altered bone metabolism in individuals receiving the newer anticonvulsants (specifically lamotrigine, topiramate, vigabatrin and gabapentin). The mechanisms of AED-associated bone disease are not clearly elucidated; however, several theories have been proposed to explain the link. No definitive guidelines for evaluation or treatment have yet been determined.

Regional and hormone-dependent effects of apolipoprotein E genotype on changes in bone mineral in perimenopausal women

We studied 479 perimenopausal Danish women aged 45-58 years to examine differences between APOE genotypes with respect to (1) baseline total body bone mineral density (BMD) and densities measured in five different regions (ultradistal forearm, proximal forearm, lumbar spine, femoral neck, and total hip region); (2) serum levels of alkaline phosphatase, bone isoenzyme alkaline phosphatase, osteocalcin, parathyroid hormone (PTH), 25-hydroxyvitamin D, and urine hydroxyproline/creatinine excretion ratio; and (3) changes in bone mineral during 5 years of follow-up. Baseline BMDs were identical, whereas serum levels of alkaline phosphatase and its bone isoenzyme were higher in women with APOE 2-2 and APOE 2-3 than in women with APOE 3-3 and APOE 3-4 and lower in women with APOE 4-4. Among women not receiving hormonal-replacement therapy (HRT; n = 262), those with APOE 2-2 and APOE 2-3 had 30-40% lower rates of femoral neck and total hip bone mineral loss than women with APOE 3-3 and APOE 3-4, whereas the rates of mineral loss in other skeletal regions did not differ between these APOE genotypes. Women with APOE 4-4 appeared to have lower rates of bone mineral loss in all regions. Women treated with hormones throughout the follow-up period (n = 113) gained bone mineral, and women with APOE 3-4 and APOE 4-4 gained relatively more mineral than other women. A comparison of untreated and treated women with APOE 2-3, APOE 3-3, and APOE 3-4 suggests a possible modification of the effect of APOE genotype by HRT. In conclusion, the common APOE polymorphism has a complex effect on bone metabolism in perimenopausal Danish women including possible modification by hormone use: (1) among women not receiving HRT, those with APOE*2 have lower bone mineral losses in the femoral neck and hip region than other women, and (2) among women receiving HRT, those with APOE*4 gain more bone mineral than other women.

Predicting bone loss and fracture risk with biochemical markers: A review

Numerous studies have reported associations of biochemical markers of bone turnover with rates of change in bone density. Increasing levels of both formation and resorption markers are associated with faster rates of decline in bone mineral density. The differences in bone loss rates among persons predicted from marker levels correspond to clinically significant differences in fracture risk. Markers have also been shown to predict fracture risk directly, although increases in certain markers are associated with increased risk in some studies, and other markers with decreased risk in other studies. The associations of biochemical markers with fracture risk are similar in magnitude to those for bone density and fractures. Taken together, existing data provide convincing evidence that biochemical markers can help determine which women are at increased risk of rapid bone loss and fracture.

Practical clinical application of biochemical markers of bone turnover: Consensus of an expert panel

Biochemical markers of bone turnover have emerged as powerful tools to aid in managing osteoporosis. The newer bone markers have been intensively studied for more than a decade. As a result, we can now confidently report their clinical utility in assessing risk of rapid bone loss and fracture, and monitoring therapy in postmenopausal women with or at risk of osteoporosis. In this review, we will provide a comprehensive foundation for this utility. While there are still questions remaining to be answered, bone marker technology has matured to play an essential role in patient management. We will describe, in practical terms, how bone markers can be appropriately incorporated into clinical practice today.

Influence of weight and gonadal status on total and regional bone mineral content and on weight-bearing and non-weight-bearing bones, measured by dual-energy X-ray absosorptiometry

OBJECTIVE

To evaluate the influence of weight on total body bone mineral content (BMCTB) and regional body bone mineral content (head, arms, trunk and legs). This was studied in accordance with gonadal status and the weight-bearing or non-weight-bearing status of each region.

METHODS

The study included 94 postmenopausal women (mean age 60.6 +/- 10.5 years), 36 perimenopausal women (mean age 49.0 +/- 2.3 years) and 60 premenopausal women (mean age 36.1 +/- 6.9 years). Full-body bone densitometry (DXA), for measuring total body bone and regional bone mineral content, was carried out in all the women.

RESULTS

Among these groups, the influence of 1 kg of body weight on total and regional bone mineral content (percent) did not differ (paired test P ns). In the overall group of women, paired comparison showed differences between the head and other zones measured (P = 0.036-0.004). In the overall group of women, no differences were found in the percent influence of 1 kg body weight on bone mineral content in any study zone (by ANOVA, Fisher's PLSD post hoc test and the Kruskal-Wallis test). In the overall group of women, Fisher's r to z test revealed a non-significant relationship between weight and the bone mineral content of the head (r = 0.49, P ns) but in every other region the relationship between weight and bone mineral content was significant (r = 0.36-0.54, P < 0.0001 in all).

CONCLUSIONS

The effect of body weight on BMCTB and regional did not differ significantly with either gonadal status or weight-bearing (legs) and non-weight-bearing bones (arms).

Quantification of remodeling parameter sensitivity--assessed by a computer simulation model

During normal aging and menopause, cancellous bone is lost at all skeletal sites due to remodeling-related factors: negative formation balance; temporarily increased remodeling space; and osteoclastic perforations. The relative importance of the various factors in inducing bone mass loss and perforations is still controversial. We have previously used a computer simulation model to describe the effect of several bone remodeling parameters on vertebral cancellous bone loss. The model focused on two different scenarios for the menopause and three different treatment regimens. The aim of the present study was to extend the previous study by quantifying remodeling parameter sensitivity for changes in the bone mass with the use of the computer model we had previously formulated. The menopause scenario, with increased activation frequency and increased resorption depth, was chosen as the base case scenario, and the following parameters were investigated in the sensitivity analysis: activation frequency; formation balance; resorption depth; and critical trabecular thickness. Simulations were performed for a period of 20 years starting at the age of 48 years. The analysis showed that the number of perforations and the perforation-related mass loss both exhibited a large sensitivity toward variations in the final resorption depth. However, the formation balance was the factor that was responsible for the greater part of the bone mass loss. The computer model allowed us to quantify the sensitivity of different output variables with respect to changes in some of the model parameters. This can give information about the biological mechanisms responsible for bone mass loss around the surgically induced or natural menopause and also provide an indication of the type of treatment that would be most useful in preventing the deterioration of the cancellous network.

Consensus of an international panel on the clinical utility of bone mass measurements in the detection of low bone mass in the adult population

Low bone mass, in the asymptomatic patient, predicts future fracture risk as well as high cholesterol or high blood pressure predicts the risk of heart disease or stroke. In patients without fractures, osteoporosis can be diagnosed based on the extent of reduction in bone mass below mean peak bone mass of healthy young individuals. As bone mass decreases, fracture risk increases exponentially. Prevention of the first fracture is a clinical goal. Clinical situations in which an assessment of bone mass and fracture risk affects therapeutic decisions include estrogen deficiency, vertebral abnormalities, radiographic osteopenia, asymptomatic primary hyperparathyroidism, and longterm corticosteroid therapy. Serial measurements can also be used to monitor the effects of osteoporosis treatment in certain situations. The appropriate technique and skeletal site for bone mass measurements should be chosen based on the patient's circumstances. A clinical interpretation can enhance the value of computer-generated bone mass measurement reports and enhance decision making.

Variability of vertebral and femoral postmenopausal bone loss: a longitudinal study

The rate of postmenopausal bone loss varies considerably between individuals and it has been suggested that about 1 in 3 women loses significant amount of bone mineral in the forearm. The rate of vertebral and femoral bone loss was determined by dual-energy X-ray absorptiometry throughout two consecutive 22-month periods, in 93 healthy women who had passed a natural menopause 6-60 months earlier. In all cases the bone changes were normally distributed, ranging from -6.9% to +2.8% per year in the spine and from -7% to +4.8% per year in the femur. No significant relationship was found between the two fractional rates of bone loss. When the women were stratified into three groups according to their individual rate of bone loss, we found that only 20%-47% retained their first classification during the second period of follow-up. In particular, less than 10% of the women showed a rapid rate of bone loss throughout the study. We conclude that spontaneous vertebral and femoral bone loss exhibit a great variability within the first postmenopausal years and that only a small minority of women sustain a fast rate of bone loss over several years. These results raise the question as to whether the evaluation of individual rates of bone loss at menopause might be useful in the identification of women at higher risk of osteoporosis.

Evolution of spinal bone loss and biochemical markers of bone remodeling after menopause in normal women

The main objective of this study was to describe longitudinal patterns of spinal bone loss in normal women who undergo a natural menopause. The second objective was to determine if a proportion of women suffer excessively rapid postmenopausal bone loss from the spine. If this was the case it was the aim to devise a means of predicting the woman at excess risk; but if all women lost bone at similar rates, the aim was to document changing loss rates over the first 5-8 postmenopausal years. Responding women in six suburban general practices recalled for cervical smears who had their last menstrual period 9- 36 months previously were invited to participate in a longitudinal study of bone loss and the biochemical markers plasma osteocalcin and urinary hydroxyproline. Sixty-four subjects agreed to participate, a response rate of 80%. In the ensuing 5 years, six received hormone replacement therapy and are not reported on. The main outcome measures were rates of spinal bone loss over 5 years, measured by dual photon absorptiometry, and radial bone loss over the first 2 years measured to quantitative computed tomography. Spinal bone loss was similar between individuals, with 94% of the variability in the data being accounted for by a statistical model that assumed parallel rates of bone loss. A less restrictive model allowing women to have different rates of spinal bone loss accounted for 12% more of the remaining variance in the data than the previous model. However, rates of radial bone loss were more dissimilar between women than rates of spinal loss. The results of the biochemical data collected serially showed that the plasma osteocalcin rose slowly to a plateau at 5 years postmenopause; in contrast, the hydroxyproline fell progressively with time over the whole period of study. These results were interpreted as being consistent with diminishing rates of bone destruction which gradually reequilibrated with bone formation as time passed after menopause.