Cancer-treatment-induced bone loss, part 1

PURPOSE

The pathophysiology, frequency, sequelae, diagnosis, and treatment of cancer-treatment-induced bone loss (CTIBL) are discussed.

SUMMARY

CTIBL is a long-term complication associated with cancer therapies that can directly or indirectly affect bone metabolism. Although CTIBL can occur in any patient receiving a cancer therapy known to cause bone loss, CTIBL is most common in patients with breast or prostate cancer who receive chemotherapy, hormone therapy, or surgical castration, as these can cause hypogonadism and induce bone loss. CTIBL causes bone fragility and an increased susceptibility to fractures; therefore, prevention, early diagnosis, and treatment of CTIBL are essential to decrease the risk of fracture. Bone loss occurs more rapidly and tends to be more severe in patients with CTIBL compared with those with normal age-related bone loss. Fractures of the hip, vertebra, and wrist are the fractures most commonly associated with bone loss. CTIBL is diagnosed by measuring bone mass using bone densitometry. Treatment of CTIBL consists of changing diet and lifestyle such as optimizing calcium and vitamin D intake, exercising, modifying behaviors known to increase the risk of CTIBL and pharmacologic therapy with hormone replacement therapy (HRT), selective estrogen-receptor modifiers (SERMs), calcitonin, or a bisphosphonate.

CONCLUSION

Early identification and treatment of CTIBL are essential to prevent fractures. Patients should be instructed to optimize calcium and vitamin D intake, exercise regularly, and modify lifestyle behaviors known to cause bone loss. Patients with CTIBL should be treated with an oral or i.v. bisphosphonate; SERMs or HRT may be an option in some patients if contraindications do not exist.

New patients: should children be treated differently?

Inflammatory bowel disease (IBD) in childhood is often diagnosed at a vulnerable time of growth and development, and is recognized as one of the most significant chronic gastrointestinal diseases to affect children. Children and adolescents with IBD are at increased risk of complications as a result of malnutrition secondary to reduced appetite, increased metabolism and decreased absorptive capacity. The most common and serious complications are growth failure, bone demineralization and impaired psychosocial development. These issues add to the complexity of childhood IBD management and it is essential that adequate medical management is in place to prevent these long-term complications. Current treatment options include 5-aminosalicylic acid, antibiotics, corticosteroids, nutritional therapy and immunomodulators used to induce and maintain remission; some are specifically employed to maintain a steroid free long-term remission. As a general rule, long-term corticosteroid use should be avoided to reduce the risk of bone demineralization and growth failure. Newer treatment options such as infliximab have been shown to be effective for inducing and prolonging remission of Crohn's disease in children and paediatric use of infliximab is likely to increase in the near future. A recent case report, involving a 15-year old boy presenting with abdominal pain and bloody diarrhoea, illustrates the difficulty in correctly diagnosing IBD in children and the need for optimizing therapy to achieve treatment success.

Bone demineralization and vertebral fractures in endogenous cortisol excess: role of disease etiology and gonadal status

INTRODUCTION

The effects of endogenous cortisol (F) excess on bone mass and vertebral fractures have still not been thoroughly investigated. The aim of this cross-sectional case-control study was to investigate factors influencing bone demineralization and vertebral fractures in different conditions of F excess, i.e. Cushing's disease and adrenal and ectopic Cushing's syndrome.

MATERIALS AND METHODS

Eighty consecutive patients and 80 controls were prospectively enrolled: 37 patients (21 females) with pituitary ACTH-secreting adenoma, 18 (14 females) with adrenocortical adenoma, 15 (11 females) with adrenal carcinoma of mixed secretion, and 10 (three females) with ectopic ACTH secretion. The groups had similar age. At diagnosis, bone mineral density (BMD) was determined by the dual-energy x-ray absorptiometry technique at the lumbar spine (L1-L4) and femoral neck; vertebral fractures were investigated by standard spinal radiographs.

RESULTS

When comparing the groups with different etiology of F excess, the patients with ectopic ACTH secretion had higher F and lower BMD values than the other subgroups. Morning F (P = 0.03) and testosterone levels (P = 0.04) correlated with lumbar BMD. Vertebral fractures were found in 61 (76%) of the patients, were multiple in 52 (85%) of the cases, and clinically evident in 32 (52%). Only multiple fractures were more frequent in patients with ectopic ACTH hypersecretion (P < 0.05). Lumbar spine BMD was the best predictor of vertebral fractures (P < 0.01). Surprisingly, amenorrheic and eumenorrheic women had similar BMD values and fracture prevalence.

CONCLUSION

A high prevalence (76%) of vertebral fracture was revealed, regardless of the etiology of the patients' hypercortisolism. The harmful effects of F excess at the spine were partly counterbalanced by the increased androgen production but were not affected by gonadal status in women.

Association between phosphate removal and markers of bone turnover in haemodialysis patients

BACKGROUND

As the main mineral reservoir, bone acts as a calcium (Ca) and phosphate buffering system. Accordingly, phosphate removal by haemodialysis (HD) might be theoretically influenced by bone turnover, as well as by the interaction of regulatory molecules, such as PTH and osteoprotegerin (OPG). The present study investigated the relationship between these variables and phosphate removal by HD.

METHODS

Blood samples for serum Ca, phosphate, bicarbonate, intact PTH, PTH (1-84), bone alkaline phosphatase, tartrate-resistant acid phosphatase 5b, OPG and receptor activator of nuclear factor-kappaB ligand (RANKL) were obtained in 28 HD patients. Phosphate removal was measured by a continuous collection of the dialysate.

RESULTS

Pre-dialysis serum phosphate concentration is the critical factor in determining dialytic phosphate removal. However, multiple regression analysis reveals that phosphate removal is better explained by a combination of factors than by phosphate concentration alone. In this model, the PTH/OPG ratio is an additional positive factor, whereas age and vitamin D treatment are negative factors. Patients with pre-HD bicarbonate higher than 20 mEq/l had higher serum phosphate and, accordingly, higher phosphate removal; of interest, these individuals also have significant differences in RANKL/OPG. Mean (SD) OPG levels were significantly higher than that in the healthy population (16.2 (12.5) pmol/l; these values correlated with age (r = 0.4, P<0.04). Mean serum RANKL (1.03 (1.02) pmol/l) was within the range of normal individuals.

CONCLUSIONS

Dialytic phosphate removal has a crucial, direct relationship with pre-HD plasma phosphate levels. However, the phenomenon of phosphate removal is more precisely explained using a more complex relationship, defined by the interaction between serum phosphate, PTH/OPG, age and vitamin D administration. Serum RANKL levels are first reported in HD patients, and are not different from the normal population.

Muscle strength is a determinant of bone mineral content in the hemiparetic upper extremity: implications for stroke rehabilitation

Individuals with stroke have a high incidence of bone fractures and approximately 30% of these fractures occur in the upper extremity. The high risk of falls and the decline in bone and muscle health make the chronic stroke population particularly prone to upper extremity fractures. This was the first study to investigate the bone mineral content (BMC), bone mineral density (BMD), and soft tissue composition of the upper extremities and their relationship to stroke-related impairments in ambulatory individuals with chronic stroke (onset >1 year). Dual-energy X-ray absorptiometry (DXA) was used to acquire total body scans on 56 (22 women) community-dwelling individuals (>or=50 years of age) with chronic stroke. BMC (g) and BMD (g/cm2), lean mass (g), and fat mass (g) for each arm were derived from the total body scans. The paretic upper extremity was evaluated for muscle strength (hand-held dynamometry), impairment of motor function (Fugl-Meyer motor assessment), spasticity (Modified Ashworth Scale), and amount of use of the paretic arm in daily activities (Motor Activity Log). Results showed that the paretic arm had significantly lower BMC (13.8%, P<0.001), BMD (4.5%, P<0.001), and lean mass (9.0%, P<0.001) but higher fat mass (6.3%, P=0.028) than the non-paretic arm. Multiple regression analysis showed that lean mass in the paretic arm, height, and muscle strength were significant predictors (R2=0.810, P<0.001) of the paretic arm BMC. Height, muscle strength, and gender were significant predictors (R2=0.822, P<0.001) of lean mass in the paretic arm. These results highlight the potential of muscle strengthening to promote bone health of the paretic arm in individuals with chronic stroke.

Reduced Loss of Hand Bone Density With Prednisolone in Early Rheumatoid Arthritis

BACKGROUND

Bone damage in rheumatoid arthritis presents as osteoporosis and joint erosions. Prednisolone has been shown to reduce the rate of hand joint destruction as seen on radiography but has not been shown to reduce the rate of hand bone loss.

METHODS

In a double-blind study comparing oral prednisolone (7.5 mg/d for 2 years) with placebo, hand bone density assessed with digital x-ray radiogrammetry was examined in 95 patients with rheumatoid arthritis with disease duration of less than 2 years.

RESULTS

The mean loss of hand bone density was less in prednisolone-treated patients compared with placebo-treated patients at the 1-year follow-up (-0.011 vs -0.022 g/cm(2)) (P = .005) and at the 2-year follow-up (-0.026 vs -0.039 g/cm(2)) (P = .03). The mean percentage group difference in loss of hand bone density was 2.8% (P = .004) at the 1-year follow-up and 3.5% (P = .01) at the 2-year follow-up. In the first year, C-reactive protein, a marker of inflammation, was strongly correlated with hand bone loss in placebo-treated patients but not in prednisolone-treated patients, suggesting that prednisolone breaks the link between bone loss and inflammation.

CONCLUSIONS

To our knowledge, this is the first double-blind randomized study to show that disease-related loss of hand bone density in rheumatoid arthritis can be decelerated by prednisolone. This finding suggests that the deleterious effect of prednisolone on bone may be counteracted by its anti-inflammatory effect.

Vitamin E provides protection for bone in mature hindlimb unloaded male rats

The deleterious effects of skeletal unloading on bone mass and strength may, in part, result from increased production of oxygen-derived free radicals and proinflammatory cytokines. This study was designed to evaluate the ability of vitamin E (alpha-tocopherol), a free-radical scavenger with antiinflammatory properties, to protect against bone loss caused by skeletal unloading in mature male Sprague-Dawley rats. A 2 x 3 factorial design was used with either hindlimb unloading (HU) or normal loading (ambulatory; AMB), and low-dose (LD; 15 IU/kg diet), adequate-dose (AD; 75 IU/kg diet), or high-dose (HD; 500 IU/kg diet) vitamin E (DL-alpha-tocopherol acetate). To optimize the effects of vitamin E on bone, dietary treatments were initiated 9 weeks prior to unloading and continued during the 4-week unloading period, at which time animals were euthanized and blood and tissue samples were collected. Serum vitamin E was dose-dependently increased, confirming the vitamin E status of animals. The HD treatment improved oxidation parameters, as indicated by elevated serum ferric-reducing ability and a trend toward reducing tissue lipid peroxidation. Histomorphometric analysis of the distal femur revealed significant reductions in trabecular thickness (TbTh), double-labeled surface (dLS/BS), and rate of bone formation to bone volume (BFR/BV) due by HU. AMB animals on the HD diet and HU animals on the LD diet had reduced bone surface normalized to tissue volume (BS/TV) and trabecular number (TbN); however, the HD vitamin E protected against these changes in the HU animals. Our findings suggest that vitamin E supplementation provides modest bone protective effects during skeletal unloading.

The next small step

The microgravity experienced in space missions has serious effects on human physiology. How to get a crew to Mars in an optimal state for landing and exploration remains a matter of some debate

Modern analysis of bone loss mechanisms in microgravity

A summary of results of investigations by the author and a brief review of some literature data on human bone tissue deprived of mechanical loading (spaceflight, hypokinesia) is given. The direction and markedness of changes in bone mass--the bone mineral density and the bone mineral content--in different skeletal segments depend on their position relative to the gravity vector. A theoretically expected bone mass reduction was revealed in the trabecular structures of the bones of the lower part of the skeleton (local osteopenia). In the upper part of the skeleton, an increase in the bone mineral content is observed, which is considered as a secondary response and is due to redistribution of body fluids cephalad. The main cause of osteopenia is mechanical unloading. Arguments are presented that osteocyte osteolysis, delayed osteoblast histogenesis, and osteoclast resorption provoked by rearrangement in the hierarchy of the systems of fluid volume and ion regulation, and the endocrine control of calcium homeostasis are the main mechanisms of osteopenia.

[Current views on the etiopathogenesis of idiopathic osteoporosis and osteopenia in the developmental period]

The paper presents current literature review on the clinical features and possible etiopathogenetic factors in idiopathic osteoporosis and osteopenia in children and adolescents. Genetic and environmental factors determining bone mass growth are included. The effect of cytokines and hormones in the regulation of bone remodelling has been discussed in detail. Most recent studies have demonstrated that cytokines are involved in bone formation and resorption by their direct influence on the activity of osteoclasts and osteoblasts. In this way they affect the state of dynamic balance between the process of bone formation and resorption, and thus the mineralization of the skeleton.

Bone density loss after spinal cord injury: elite paraplegic basketball players vs. paraplegic sedentary persons

OBJECTIVE

To compare the bone mineral density of elite paraplegic basketball players with the values obtained from their paraplegic sedentary counterparts.

DESIGN

A total of 17 male paraplegic basketball players and 17 male paraplegic sedentary persons were included in the study. Bone mineral densities of the distal third of radius of the dominant arm, L2-L4 spine, and trochanters, Ward's triangles, and the femoral necks of both hips were measured.

RESULTS

The densities of trochanters, Ward's triangles, and the femoral necks were found to be decreased in both groups, with no significant difference between them. The densities of lumbar and radial regions were found to be increased in both groups. Radial density was significantly higher in paraplegic basketball players than in paraplegic sedentary patients, whereas the groups were not significantly different for lumbar density.

CONCLUSIONS

Wheelchair basketball in spinal cord-injured patients was associated with greater bone density in distal radius compared with sedentary paraplegics. However, it was not associated with greater density below the injury level.

Bone loss in the contralateral asymptomatic hand in patients with complex regional pain syndrome type 1

Regional osteoporosis was seen radiographically in clinically affected areas in patients with complex regional pain syndrome type 1 (CRPS1). The aim of the this study was to investigate whether bone loss developed in the contralateral hand in patients with unilateral CRPS1 of the hand. Thirty-two patients with CRPS1 of the hand were included in this study. Bone mineral density was measured in the left proximal femur and both ultradistal radiuses, using dual-energy X-ray absorptiometry. The subjects were classified as grades 1 to 3 according to the T-score of both ultradistal radiuses (densitometric grades): grade 1, both radiuses were normal; grade 2, bone loss was determined only in the affected radius; and grade 3, there was bone loss in both radiuses. Twenty (62.5%) patients had bone loss in the affected hand; 11 patients (34.4%) had bone loss only on the affected side and 9 patients (28.1%) had bone loss on both sides. The mean duration of the period between the diagnosis of the injury and the measurement of bone density was 1.9 +/- 0.6 months in patients with grade 1, 3.1 +/- 1.0 months in patients with grade 2, and 5.5 +/- 2.2 months in patients with grade 3. The Spearman test showed a significant correlation between the period of injury and the densitometric grade ( R = 0.774; P = 0.0001). In conclusion, the current study of patients with CRPS1, showed that the bone loss in the asymptomatic contralateral hand developed at a later stage than that in the affected hand. This bone loss was less frequent and of a lower degree in the asymptomatic contralateral hand than in the affected hand. The bone loss in the asymptomatic contralateral hand could be explained by the loss of sympathetic tone in CRPS1 and contralateral sympathetic innervation.

A randomized controlled trial of calcium with vitamin D, alone or in combination with intravenous pamidronate, for the treatment of low bone mineral density associated with Crohn's disease

BACKGROUND

Osteoporosis is a common complication of Crohn's disease.

AIM

To study the effect on the bone mineral density of a bisphosphonate (pamidronate) given intravenously, in combination with oral calcium and vitamin D supplements, compared with oral calcium and vitamin D supplements alone.

METHODS

Seventy-four patients with Crohn's disease and low bone mineral density at the lumbar spine and/or hip were randomized to receive either a daily dose of 500 mg of calcium with 400 IU of vitamin D alone or in combination with four three-monthly infusions of 30 mg of intravenous pamidronate over the course of 12 months. The main outcome measure was the change in bone mineral density at the lumbar spine and hip, measured by dual X-ray absorptiometry, at baseline and 12 months.

RESULTS

Both groups gained bone mineral density at the lumbar spine and hip after 12 months. There were significant (P < 0.05) changes in the pamidronate group, with gains of + 2.6%[95% confidence interval (CI), 1.4-3.0] at the spine and + 1.6% (95% CI, 0.6-2.5) at the hip, compared with gains of + 1.6% (95% CI, - 0.1-3.2) and + 0.9% (95% CI, - 0.4-2.1) at the spine and hip, respectively, in the group taking vitamin D and calcium supplements alone.

CONCLUSIONS

In patients with Crohn's disease and low bone mineral density, intravenous pamidronate significantly increases the bone mineral density at the lumbar spine and hip.

[Changes in bone density in hemodialysed women treated with transdermal hormone replacement therapy]

OBJECTIVES

Renal insufficiency in women can cause menstrual disturbances and changes of hormonal profile leading to the decrease of bone mass density. Drug administration during dialysis also influences the bone density and increases the risk of osteoporosis. The aim of the study is to assess the effect of transdermal hormonal replacement therapy (HRT) in hemodialysed patients with secondary amenorrhea on bone density.

MATERIAL AND METHODS

10 women aged from 22 to 45 years old were enrolled in the study. They received 17 beta-estradiol and norethisterone acetate in patches during 12 cycles. Densitometer of lumbar spine and serum estradiol concentration were measured before and after 12 cycles of therapy.

RESULTS

The recurrence of regular vaginal bleeding, the increase of estradiol levels and bone mass density rate about 6% were observed.

CONCLUSIONS

Transdermal hormonal replacement therapy in hemodialysed women with secondary amenorrhea revealed the efficacy of the treatment and prevention from osteoporosis.

Periimplant Bone Healing under Experimental Hepatic Osteodystrophy Induced by a Choline-Deficient Diet: A Histomorphometric Study in Rats

BACKGROUND

Osseointegration and success of an implant involve the interaction of local and systemic factors such as bone metabolic diseases.

PURPOSE

The purpose of this study was to evaluate the effect of experimental hepatic osteodystrophy induced by a choline-deficient diet on periimplant bone healing.

MATERIALS AND METHODS

Laminar titanium implants were placed in the tibias of five groups of Wistar rats: those with a (1). controlled diet for 15 days; (2). choline-deficient diet for 15 days; (3). controlled diet for 30 days; (4). choline-deficient diet for 30 days; (5). choline-deficient diet for 15 days and a controlled diet for 15 days (refeeding). Body weight and food intake, hematocrit, and hemoglobinemia were evaluated. The animals were killed at 15 or 30 days post implantation. The liver, kidneys, and tibias were resected and fixed in 20% formalin solution. The tibias were radiographed and processed for histomorphometric evaluation of the periimplant bone area.

RESULTS

Histologic studies revealed steatosis in the liver but no alterations in the kidneys. Rats fed a choline-deficient diet showed periimplant bone healing with marked qualitative and quantitative alterations. The periimplant bone area was 28% and 75% lower in experimental animals than in controls at 15 and 30 days, respectively.

CONCLUSIONS

Liver alterations caused by a choline-deficient diet alter periimplant osteogenesis qualitatively and quantitatively.

[Changes of osteocalcin in bone and bone marrow in tail suspended rats]

OBJECTIVE

To study osteocalcin [correction of osteocakin] (OC) changes in bone and marrow and calcium deposition in bone and cartilage under simulated weightlessness.

METHOD

Twenty SD rats were randomly divided into 14 d and 28 d tail suspension group and 2 corresponding control groups. Histological samples were in situ hybridized and trichrome stained.

RESULT

OC expression of bone and marrow of rats were lower in tail suspended rats than that in the control (P<0.05). OC expression in 14 d tail suspended rats were higher than that in 28 d tail suspended group (P<0.05). Mineralization was inhibited, and demineralization of femur [correction of furmer] and cartilage mineralized matrix was prominent. Demineralization was more prominent in 28 d group.

CONCLUSION

OC levels in bone and marrow of rats were lower after tail suspension. Calcium deposition was inhibited in bone and cartilage. Demineralization was prominent after long term hindlimb unloading.

Model of the mechanism of Ca loss by bones under microgravity and earth conditions

A comparative characterization of crystal structure, morphology, sizes, and orientation in Ca phosphate precipitation from aqueous solutions, the mineral phase in bones, and mineral deposits on cardiac valves has been performed by high-resolution transmission electron microscopy to model possible mechanisms of Ca loss by bones. Physiological changes occurring in organisms can lead to deep perturbations of the natural calcium phosphate supersaturation and its local distribution, which in turn influences the phase composition, morphology, and organization of the mineral phase. Formation of crystals with larger size or of two distinct phases instead of the single hydroxyapatite one can result in the deterioration of the Ca balance in bone and tissue destruction as well as the possible misorientation (or spread of orientation) between HAP crystals newly formed in the bone.

Changes in serum 1,25-dihydroxyvitamin D3 and mRNAs for osteocalcin and alkaline phosphatase in femur unloaded by tail suspension in rats

To elucidate the mechanism involved in the development of disuse atrophy of bone by skeletal unloading, changes in osteocalcin and alkaline phosphatase mRNAs, markers for bone formation, were studied in the hind limb bones of tail-suspended rats. Tail suspension for 8 and 14 days resulted in a significant decrease in osteocalcin mRNA in the femur when compared with age-matched non-suspended controls. Serum 1,25-dihydroxyvitamin D3 decreased to 60% of the control level after 8 days of skeletal unloading but regained almost normal levels over the next 7 days. Since it is known that vitamin D3 up regulates and glucocorticoid down regulates transcription of the osteocalcin gene, the endocrine response evoked by tail suspension may have aggravated the disuse atrophy caused by skeletal unloading in this study.

Loss of bone mineral of the hip and proximal tibia following rupture of the Achilles tendon

In a prospective uncontrolled study 12 patients suffering from a rupture of the Achilles tendon treated operatively with surgical repair and post-operative immobilization in a short plaster cast for 6 weeks had bilateral measurements of bone mineral content (BMC) of the proximal tibia and bone mineral density (BMD) of the femoral neck and greater trochanter. The measurements were performed by dual energy X-ray absorptiometry (DEXA) and scans were performed post-operatively within 7 days after the operation and with follow up after 6 weeks, 3, 6, and 12 months. In the operated legs, BMC of the proximal tibia showed a progressive decrease reaching a total bone loss of 6.4% (95%-CL: -10.6%; -2.3%) 1 year after the injury. Bone mineral density at the hip of the operated legs also decreased significantly and 1 year after the injury BMD was 2.5% (95%-CL: -5.5%; 0.5%) and 6.8% (95%-CL: -9.8%; -3.7%) below the initial value in, respectively, the femoral neck and greater trochanter. Patients with a previous Achilles tendon rupture must be considered to be some years ahead in their natural osteoporotic process of the bones of the affected legs, and an increased risk of osteoporotic fractures must be considered not to be only theoretical.

The physical price of a ticket into space

As a direct consequence of exposure to microgravity astronauts experience a number of physiological changes, which can have serious medical implications when they return to Earth. Most immediate and significant are the head-ward shift of body fluids and the removal of gravitational loading from bone and muscles, which lead to progressive changes in the cardiovascular and musculoskeletal systems. Cardiovascular adaptations result in an increased incidence of orthostatic intolerance (fainting) post-flight, decreased cardiac output and reduced exercise capacity. Changes in the musculoskeletal system contribute significantly to the impaired functions experienced in the post-flight period. The underlying factor producing these changes is the absence of gravity. Countermeasures, therefore, are designed primarily to simulate Earth-like movements, stresses and system interactions. Exercise is one approach that has received wide operational use and acceptance in both the US and Russian space programmes, and has enabled humans to stay relatively healthy in space for well over a year. Although it remains the most effective countermeasure currently available, significant physiological degradation still occurs. The development of other countermeasures will therefore be necessary for longer duration missions, such as the human exploration of Mars.

Calcium metabolism under stress and in repose

Derangement of calcium metabolism, although perhaps not as dramatic as that of the cardiovascular or vestibular systems, constitutes one of the major threats to the health of participants in exploration of space. On the basis of studies in immobilized subjects, the clinical disorders most likely to be encountered during prolonged space flight are primarily the consequence of an imbalance between bone formation and resorption (favoring the latter): (1) loss of skeletal mass, leading to osteoporosis; (ii) hypercalcemia; and (iii) hyper-calciuria, with the attendant risk of nephrolithiasis. By itself, loss of skeletal mass would not be expected to pose an in-flight hazard, but hypercalcemia or nephrolithiasis could jeopardize lives or mission success. Such data as are available from in-flight studies tend to support the use of immobilization as a terrestrial model for alterations in calcium metabolism during space flight. A variety of prophylactic measures have been attempted with this model in an effort to modify the observed disorders. Although there is some evidence that hypercalcemia and hypercalciuria can be reduced or prevented, negative calcium balance has not been completely reversed. Perhaps the most successful prophylactic measure utilized to date has been dietary supplementation of both calcium and inorganic phosphate. With the wide variety of excellent study tools which are currently available for application to this field, significantly increased efforts are clearly required both to define the basic mechanism of immobilization-induced skeletal losses and to devise new prophylactic or therapeutic approaches.

[Bone metabolism in adolescent girls with short course of anorexia nervosa]

OBJECTIVE

The objective of this study was to determine the prevalence of bone mass reduction and determine its causes in young girls with short course of anorexia nervosa (AN).

METHOD

Bone mineral density (BMD)of lumber spine by dual energy x-ray absorptiometry, total alkaline phosphatase (TAP), bone-Gla protein (BGP), urine deoxypyridinoline (DPYR), DPYR, urine calcium, sex hormones were measured in 24 in-patient girls with diagnosed AN and 20 healthy volunteers.

RESULTS

Girls with AN had a significantly lower BMD than their age-matched controls. Osteopenia and osteoporosis were present even in the group with AN diagnosed within the previous 12 months. BMD correlated negatively with minimal BMI and positively with the duration of regular menses before AN onset. BGP and DPYR were significantly lower in AN patient than in the control group. Values of urine calcium of AN patients were comparable with control group, but showed a positive correlation with disease duration.

DISCUSSION

Reduction of bone mineral density is present in girls with short course of AN. Nutritional status is the most important predictor of BMD. Bone metabolism is decreased in the early stages of the disease.

[Osteoporosis and demineralization: a semantic confusion]

Osteoporosis is the most frequent demineralizing disease. However, when a demineralized vertebra is identified, other diseases must be ruled out in the course of diagnosis. Through three clinical cases, we analyze pitfalls that have delayed the diagnosis of one rare, but unfortunately lethal, aetiology: multiple myeloma.

Bone mineral density in adolescent girls with anorexia nervosa--a cross-sectional study

The total body and lumbar spine bone mineral density (BMD) were measured in order to determine the prevalence and possible risk factors of decreased BMD in anorexia nervosa (AN).

SUBJECTS

Sixty-one in-patient girls with DSM III-R AN: age 14.7+/-2.16 years; duration of AN 12.9+/-15.1 months; percentage of ideal body weight 70+/-8.7%; body mass index score -1.62+/-0.79.

METHOD

Total body (in 61 patients) and lumbar spine BMD (in 43 patients), content of lean and fat tissue mass were measured by DXA during the first month of treatment.

RESULTS

Low total body BMD was found in 23.7% and low lumbar spine BMD in 36.6% of patients. There was a negative correlation between BMD and age, age of menarche, degree of undernourishment, duration of AN and amenorrhea. A step-wise linear regression analysis revealed that age of menarche was the most important factor related to BMD in this group.