Body composition and vertebral fracture risk in female patients treated with glucocorticoid

The Role of Trunk Musculature in Osteoporotic Vertebral Fractures: Implications for Prediction, Prevention, and Management

This review examines the current evidence for associations between vertebral fractures (VFx), the most common type of fracture in older adults, and trunk muscles, which are intimately tied to spinal loading and function. Individuals with prevalent VFxs have more fat infiltration in the trunk muscles, lower trunk extension strength, and altered muscle activation patterns. However, no longitudinal studies have examined whether assessment of trunk muscle can contribute to prediction of fracture risk. A few studies report that exercise interventions targeting the trunk muscles can reduce the risk of VFx, improve trunk strength and endurance in patients who have had a VFx, and reduce the risk of falling, a common cause of VFx, but the quality of evidence is low. Trunk muscles likely have an important role to play in prediction, prevention, and management of VFx, but additional longitudinal studies and randomized controlled trials are needed to clarify this role.

Epidemiology of Vertebral Fractures

Vertebral fractures are one of the most common fractures associated with skeletal fragility and can cause as much morbidity as hip fractures. However, the epidemiology of vertebral fractures differs from that of osteoporotic fractures at other skeletal sites in important ways, largely because only one quarter to one-third of vertebral fractures are recognized clinically at the time of their occurrence and otherwise require lateral spine imaging to be recognized. This article first reviews the prevalence and incidence of clinical and radiographic vertebral fractures in populations across the globe and secular trends in the incidence of vertebral fracture over time. Next, associations of vertebral fractures with measures of bone mineral density and bone microarchitecture are reviewed followed by associations of vertebral fracture with various textural measures of trabecular bone, including trabecular bone score. Finally, the article reviews clinical risk factors for vertebral fracture and the association of vertebral fractures with morbidity, mortality, and other subsequent adverse health outcomes.

Relationship between Bone Mineral Density and Spinal Muscle Area in Magnetic Resonance Imaging

Background

Bone mineral density (BMD) is known to have a positive correlation with lean body mass. Several studies have also reported the positive correlation between muscle power and BMD. From this point of view, we hypothesized BMD of lumbar spine to have a positive correlation with muscle mass.

Methods

Seventy-nine female patients aged between 60 and 75 years old and who underwent magnetic resonance imaging (MRI) and BMD studies were included. Muscle mass in spine MRI was defined by the sum of the average muscle area of three axial images for each disc level. Lumbosacral muscle is the sum of paraspinal muscle and psoas muscle.

Results

In correlation analysis, paraspinal muscle mass showed positive correlation with BMD of lumbar spine. Lumbosacral muscle mass showed positive correlation with BMD of trochanteric area of the femur. However, BMD of other area showed no significant correlation with muscle mass.

Conclusions

Therefore, postmenopausal women older than 60 years with a well developed spine muscle mass, have a high BMD.

Interaction between Muscle and Bone

The clinical significance of sarcopenia and osteoporosis has increased with the increase in the population of older people. Sarcopenia is defined by decreased muscle mass and impaired muscle function, which is related to osteoporosis independently and dependently. Numerous lines of clinical evidence suggest that lean body mass is positively related to bone mass, which leads to reduced fracture risk. Genetic, endocrine and mechanical factors affect both muscle and bone simultaneously. Vitamin D, the growth hormone/insulin-like growth factor I axis and testosterone are physiologically and pathologically important as endocrine factors. These findings suggest the presence of interactions between muscle and bone, which might be very important for understanding the physiology and pathophysiology of sarcopenia and osteoporosis. Muscle/bone relationships include two factors: local control of muscle to bone and systemic humoral interactions between muscle and bone. As a putative local inducer of muscle ossification, we found Tmem119, a parathyroid hormone-responsive osteoblast differentiation factor. Moreover, osteoglycin might be one of the muscle-derived humoral bone anabolic factors. This issue may be important for the development of novel drugs and biomarkers for osteoporosis and sarcopenia. Further research will be necessary to clarify the details of the linkage of muscle and bone.

The association between lean mass and bone mineral content in the high disease activity group of adult patients with juvenile idiopathic arthritis

BACKGROUND

The study is aimed to evaluate body composition and bone status in adolescent and adult patients with active juvenile idiopathic arthritis (JIA) untreated with tumor necrosis factor alpha inhibitors.

METHODS

Adult patients (12 male and 19 female) with active JIA and 84 healthy age- and gender- matched controls were enrolled into the study. Body composition (tissue mass in grams, lean mass, fat mass and bone mineral content as a fraction of tissue mass) and areal bone mineral density parameters (aBMD) at the lumbar spine, proximal femur, femoral neck, distal radius and total body were assessed using dual energy x-ray absorptiometry (DXA), and correlated with clinical characteristics of the disease and physical performance tests. Disease activity was assessed using high-sensitivity C-reactive protein (hsCRP) and disease activity score 28 (DAS 28). Differences between the groups were tested by t-test, and One-way ANOVA. Correlations were assessed using the Pearson correlation coefficients and multiple linear regression analysis. Significances were counted at the 0.05 level.

RESULTS

In patients with clinically active JIA (DAS 28, 6.36 ± 0.64, hsCRP, 18.36 ± 16.95 mg/l), aBMD at all measured sites, bone mineral content (BMC) and lean mass were reduced, and fat mass was increased as compared with healthy controls. Significant negative correlations were observed between BMC and disease duration, use of glucocorticoids (GCs), and fat mass, respectively. A positive correlation was found between BMC and lean mass, and between the body fat fraction and the use of GCs. Using multiple linear regression analysis, lean mass was the only significant predictor of BMC of total body both in men and women, and of BMC of legs (only in men). Lean mass was also the only predicting factor of total proximal femur BMD and femoral neck BMD. No significant correlations have been determined among the body composition parameters and DAS 28 or hsCRP endpoints.

CONCLUSIONS

In adult patients with long-term active JIA, lean mass was the main determining factor of total body and leg BMC, and total proximal femur and femoral neck aBMD.

Serum undercarboxylated osteocalcin was inversely associated with plasma glucose level and fat mass in type 2 diabetes mellitus

Although recent animal studies have shown that undercarboxylated osteocalcin acts as a hormone regulating glucose metabolism and fat mass, little is known about the relationships in humans. We reported here for the first time that undercarboxylated osteocalcin were associated with glucose/fat metabolism in patients with type 2 diabetes.

INTRODUCTION

Recent studies have shown that undercarboxylated osteocalcin (ucOC) acts as a hormone regulating glucose metabolism and fat mass. We investigated the relationship between ucOC as well as other bone turnover markers [serum OC, bone-specific alkaline phosphatase (BAP), and urinary N-terminal cross-linked telopeptide of type-I collagen] versus serum levels of glucose, fasting serum C-peptide, and adiponectin as well as the amount of fat mass in type 2 diabetes.

METHODS

A total of 180 men and 109 postmenopausal women were consecutively recruited, and radiographic and biochemical characteristics were collected. Fat mass was measured by dual X-ray absorptiometry (DXA) and computed tomography (CT).

RESULTS

In men, ucOC negatively correlated with percent trunk fat (%trunk fat; by DXA) and visceral/subcutaneous fat ratio (by CT) as well as fasting plasma glucose and HbA(1c) (at least p < 0.05). Multiple regression analysis showed that these associations were still significant independent of age, duration of diabetes, body stature, and renal function as well as glucose or fat metabolism, whereas BAP, another bone formation marker, did not correlate with any variable. On the other hand, although ucOC also negatively correlated with %fat and %trunk fat as well as HbA(1c) (at least p < 0.05) in postmenopausal women, we found no significant association in multiple regression analysis.

CONCLUSIONS

These findings suggest that ucOC is associated with plasma glucose level and fat mass in men with type 2 diabetes.

Urinary deoxypyridinoline is a BMD-independent marker for prevalent vertebral fractures in postmenopausal women treated with glucocorticoid

SUMMARY

Urinary deoxypyridinoline (DPD) level was associated with prevalent vertebral fractures in glucocorticoid (GC)-treated postmenopausal women independently of lumbar spine bone mineral density (BMD).

INTRODUCTION

Bone metabolic indices are the potential predictors of bone fragility. However, their diagnostic efficiency for identifying the risk of GC-induced vertebral fractures is still unclear. We therefore evaluated whether bone metabolic indices would assess the risk of vertebral fractures in GC-treated women.

METHODS

One hundred seventy-five women treated with GC for more than 6 months were enrolled in this study.

RESULTS

Both premenopausal and postmenopausal women with vertebral fractures had significantly higher urinary DPD levels than those without vertebral fractures. When multivariable logistic regression analysis was performed with the presence of vertebral fractures as a dependent variable and each of DPD or osteocalcin level adjusted for age, weight, height, current and maximum doses of GC, duration of GC treatment, as well as lumbar spine BMD as an independent variable, DPD level was identified as a factor associated with the presence of vertebral fractures in postmenopausal women but not in premenopausal women.

CONCLUSION

Urinary DPD level was significantly associated with prevalent vertebral fractures in GC-treated postmenopausal women independently of lumbar spine BMD.

Associations between components of the metabolic syndrome versus bone mineral density and vertebral fractures in patients with type 2 diabetes

The association of bone with the metabolic syndrome and its features, visceral fat accumulation or insulin resistance, remains unclear. We determined visceral and subcutaneous fat areas (V and S) by computed tomography on 187 men (28-83 years) and 125 postmenopausal women (46-82 years) with type 2 diabetes. Men whose V was 100 cm(2) or more had significantly lower urinary N-terminal cross-linked telopeptide of type-I collagen (p=0.005), higher femoral neck bone mineral density (FN-BMD) (p=0.004), and lower prevalence of vertebral fractures (VFs) (p=0.04) than controls. Fat mass, V, S, and lean body mass positively correlated with FN-BMD in men and with lumbar (L) and FN-BMD in women. When adjusted for weight, these correlations became negative. Urinary C-peptide positively correlated with FN-BMD in both genders. Multivariate logistic regression analysis adjusted for age, height, weight, L-BMD, duration of diabetes, and diabetes therapies identified V in men and urinary C-peptide in women as factors inversely associated with the presence of VFs [odds ratio (OR)=0.61 per SD increase, p=0.04, and OR=0.32, p=0.01, respectively]. These findings suggest that, of the components of the metabolic syndrome, body fat in gravity and hyperinsulinemia could increase FN-BMD in diabetic subjects. Visceral fat in men and hyperinsulinemia in women may protect against VFs independent of weight, L-BMD, diabetes duration, or therapies.

Glucocorticoids and the risk of osteoporosis

BACKGROUND

Glucocorticoid-induced osteoporosis (GIO) refers to a clinical condition in which a class of corticosteroids increases the susceptibility of bones to fracture. Numerous recent studies have improved our understanding of the underlying biology of this condition, whereas data from randomized controlled trials have provided clinicians with more options for prevention of GIO.

OBJECTIVE

To review the pathophysiology and epidemiology of GIO, as well as current pharmacologic treatment and prevention modalities available. To review the state of healthcare provider concordance with GIO prevention guidelines.

METHODS

Representative examples of various cellular and molecular processes underlying GIO were included, with an emphasis towards more recent discoveries. The data used to describe the epidemiology of GIO were derived from both randomized controlled studies and observational studies, framed through a discussion of known osteoporosis risk factors.

RESULTS/CONCLUSION

Progress has been made in clarifying the pathophysiologic mechanisms that result in GIO. Although the options for preventions and treatment of GIO continue to expand, provider compliance with preventive measures remains suboptimal.

The influence of lean mass in trabecular and cortical bone in juvenile onset systemic lupus erythematosus

The aim of this study was to evaluate risk factors for low bone mineral density (BMD) and vertebral fractures, in juvenile systemic lupus (JSLE). Thirty-one consecutive patients with JSLE were compared with 31 gender- and age-matched healthy controls. BMD and body composition from all participants were measured using dual-energy X-ray absorptiometry. Vertebral fractures were defined as a reduction of > or = 20% of the vertebral height for all patients. Lumbar spine and total femur BMD was significantly decreased in patients compared with controls (P = 0.021 and P = 0.023, respectively). A high frequency of vertebral fractures (22.58%) was found in patients with JSLE. Analysis of body composition revealed lower lean mass (P = 0.033) and higher fat mass percentage (P = 0.003) in patients than in controls. Interestingly, multiple linear regression using BMD as a dependent variable showed a significant association with lean mass in lumbar spine (R2 = 0.262; P = 0.004) and total femur (R2 = 0.419, P = 0.0001), whereas no association was observed with menarche age, SLE Disease Activity Index, Systemic Lupus International Collaborating Clinics/American College of Rheumatology, and glucocorticoid. This study indicates that low BMD and vertebral fractures are common in JSLE, and the former is associated with low lean mass, suggesting that muscle rehabilitation may be an additional target for bone therapeutic approach.

Serum osteocalcin level is associated with glucose metabolism and atherosclerosis parameters in type 2 diabetes mellitus

CONTEXT

Recent animal studies showed that osteocalcin action is related to not only bone metabolism but also glucose metabolism and fat mass. We investigated the relationship between two bone formation markers, serum osteocalcin and bone-specific alkaline phosphatase, and glucose metabolism, serum adiponectin, and the amount of fat mass as well as atherosclerosis parameters in men and postmenopausal women with type 2 diabetes.

METHODS

A total of 179 men and 149 postmenopausal women were recruited consecutively, and radiographic and biochemical characteristics were collected. Brachial-ankle pulse wave velocity (baPWV) and intima-media thickness (IMT) were evaluated as the parameters of atherosclerosis.

RESULTS

Multiple regression analysis adjusted for age, duration of diabetes, body mass index, and serum creatinine showed that osteocalcin negatively correlated with fasting plasma glucose and hemoglobin A(1c) in both men and postmenopausal women (P < 0.05) and with percent fat, baPWV, and IMT in men (P < 0.05). Osteocalcin positively correlated with total adiponectin in postmenopausal women (P < 0.001). After additional adjustments for systolic blood pressure, low-density lipoprotein-cholesterol, high-density lipoprotein-cholesterol, hemoglobin A(1c), and Brinkmann index, osteocalcin still significantly and negatively correlated with baPWV and IMT in men. In contrast, osteocalcin did not correlate with fasting C-peptide, and bone-specific alkaline phosphatase did not correlate with any variable in either men or postmenopausal women.

CONCLUSIONS

Serum osteocalcin is associated with glucose and total adiponectin levels, fat mass, and atherosclerosis parameters in patients with type 2 diabetes, suggesting that osteocalcin is important for not only bone metabolism but also glucose and fat metabolism.

Changes in body composition after glucocorticoid therapy in patients with systemic lupus erythematosus

The aim of this study was to evaluate the changes in body composition after glucocorticoid treatment in patients with systemic lupus erythematosus (SLE). Consecutive SLE patients were recruited for serial measurements (baseline, months 2 and 6) of bone mineral density (BMD) and body composition [bone mineral content (BMC), fat and lean mass] by dual energy X-ray absorptiometry scan after high-dose oral glucocorticoid therapy. Factors correlated with changes in body composition were evaluated. 29 SLE patients were studied (age 39.7 ± 11.5 years; 83% women with 29% postmenopausal; SLE duration 80.1 ± 80 months). Fourteen patients (48%) were glucocorticoid-naive. The mean maximum daily dosage of prednisolone was 32.9 ± 6.5 mg and the cumulative prednisolone dosage in 6 months was 2.7 ± 0.7 g. At 6 months, a significant drop in BMC of the trunk (−5.0 ± 2.2%; P = 0.04) and whole body (−1.2 ± 0.4%; P = 0.002) compared with baseline was observed, and so was the BMD of the hip (−1.7 ± 0.6%; P = 0.006) and whole body (−0.7 ± 0.3%; P = 0.01). A significant increase in the fat mass of the trunk (+14.5 ± 4.1%; P = 0.001) and limbs (+10.0 ± 3.2%; P = 0.004), but a non-significant drop in lean mass of the trunk (−3.3 ± 1.8%; P = 0.08) and limbs (−0.8 ± 2.4%; P = 0.75) also occurred. The changes in whole body BMC correlated significantly with age (ρ = −0.51; P = 0.02) and changes in total fat mass (ρ = 0.44; P = 0.02) but not with lean mass (ρ = −0.21; P = 0.27), gender, body mass index, smoking, prednisolone dosages or changes in BMD. In SLE patients, high-dose glucocorticoids lead to an early and rapid drop in bone mass, which is more serious in older patients and correlates with an increase in body fat.

Vertebral Fracture Assessment: the 2007 ISCD Official Positions

Vertebral fracture assessment (VFA) is an established, low radiation method for detection of prevalent vertebral fractures. Vertebral fractures are usually not recognized clinically at the time of their occurrence, but their presence indicates a substantial risk for subsequent fractures independent of bone mineral density. Significant evidence supporting VFA use for many post-menopausal women and older men has accumulated since the last ISCD Official Position Statement on VFA was published. The International Society for Clinical Densitometry considered the following issues at the 2007 Position Development Conference: (1) What are appropriate indications for Vertebral Fracture Assessment; (2) What is the most appropriate method of vertebral fracture detection with VFA; (3) What is the sensitivity and specificity for detection of vertebral fractures with this method; (4) When should additional spine imaging be performed following a VFA; and (5) What are the reporting obligations for those interpreting VFA images?

Glucocorticoid excess affects cortical bone geometry in premenopausal, but not postmenopausal, women

Glucocorticoid (GC) excess causes a great increase in fracture risk, but the effects of GC excess on cortical bone geometry are unknown. The present study was performed to examine the effects of GC excess on cortical bone geometry in both premenopausal and postmenopausal women. Ninety-six women receiving oral GC treatments and 10 women with Cushing syndrome (CS) were each compared to age-matched control subjects using peripheral quantitative computed tomography. Total area, periosteal circumference, and polar strength strain index (SSIp) were significantly lower in GC-treated patients compared with control subjects in premenopausal women but not in postmenopausal women. Moreover, cortical area and thickness as well as periosteal circumference and SSIp were significantly lower in patients with CS compared to controls in premenopausal women but not in postmenopausal women. Total area, cortical area, cortical thickness, periosteal circumference, as well as SSIp were significantly lower in GC-treated patients with vertebral fractures compared to those without vertebral fractures in premenopausal women but not in postmenopausal women. In conclusion, endogenous or exogenous GC excess affects bone geometry of forearms of premenopausal, but not postmenopausal, women. These effects of GC excess on bone geometry may provide a strength loss mechanism beneath increased vertebral fracture risk.

Glucocorticoid-induced osteoporosis: pathophysiology and therapy

Glucocorticoid-induced osteoporosis (GIO) is the most common form of secondary osteoporosis. Fractures, which are often asymptomatic, may occur in as many as 30-50% of patients receiving chronic glucocorticoid therapy. Vertebral fractures occur early after exposure to glucocorticoids, at a time when bone mineral density (BMD) declines rapidly. Fractures tend to occur at higher BMD levels than in women with postmenopausal osteoporosis. In human subjects, the early rapid decline in BMD is followed by a slower progressive decline in BMD. Glucocorticoids have direct and indirect effects on the skeleton. The primary effects are on osteoblasts and osteocytes. Glucocorticoids impair the replication, differentiation and function of osteoblasts and induce the apoptosis of mature osteoblasts and osteocytes. These effects lead to a suppression of bone formation, a central feature in the pathogenesis of GIO. Glucocorticoids also favor osteoclastogenesis and as a consequence increase bone resorption. Bisphosphonates are effective in the prevention and treatment of GIO. Anabolic therapeutic strategies are under investigation.

Type I diabetic bone phenotype is location but not gender dependent

Bone is highly dynamic and responsive. Bone location, bone type and gender can influence bone responses (positive, negative or none) and magnitude. Type I diabetes induces bone loss and increased marrow adiposity in the tibia. We tested if this response exhibits gender and location dependency by examining femur, vertebrae and calvaria of male and female, control and diabetic BALB/c mice. Non-diabetic male mice exhibited larger body, muscle, and fat mass, and increased femur BMD compared to female mice, while vertebrae and calvarial bone parameters did not exhibit gender differences. Streptozotocin-induced diabetes caused a reduction in BMD at all sites examined irrespective of gender. Increased marrow adiposity was evident in diabetic femurs and calvaria (endochondrial and intramembranous formed bones, respectively), but not in vertebrae. Leptin-deficient mice also exhibit location dependent bone responses and we found that serum leptin levels were significantly lower in diabetic compared to control mice. However, in contrast to leptin-deficient mice, the vertebrae of T1-diabetic mice exhibit bone loss, not gain. Taken together, our findings indicate that TI-diabetic bone loss in mice is not gender, bone location or bone type dependent, while increased marrow adiposity is location dependent.