Accuracy and precision of in vivo bone mineral measurements in sheep using dual-energy X-ray absorptiometry

We evaluated the precision and accuracy of in vivo measurements of spine bone mineral density (BMD) and bone mineral content (BMC) in five ewes using dual-energy X-ray absorptiometry (DXA, Lunar DPX-L). The short-term in vivo reproducibility expressed as the coefficient of variation (CV) varied from 0.9 to 1.6% for spine BMD and from 1 to 3.1% for spine BMC. The ex vivo measurements, performed in 20 cm of water to simulate soft tissue thickness, correlated closely with the in vivo measurements, yielding an r value of 0.98 and 0.97 for spine BMD and BMC, respectively. The accuracy was determined by comparing the total BMC of each vertebra measured in vivo with the corresponding ash weight. The correlation coefficient between the two measurements was r = 0.98, with an accuracy error of 5.6%. We concluded that the DXA allows a precise and accurate measurement of spine bone mineral in live ewes using the methodology designed for humans.

[Primary intramedullary spinal cord lymphoma in HIV patients. MRI aspects]

We report a case of an immunocompetent man who developed primary spinal intramedullary malignant lymphoma. This condition occurs in about 0.9 p. 100 of primary central nervous system non-Hodgkin lymphomas in non-AIDS patients. Magnetic resonance imaging was nonspecific but suggestive. Like the brain localization, prognosis is poor. Because of the high frequency of recurrence, usually confined to the central nervous system with neuraxis dissemination, treatment must be delivered to the entire neuraxis. But more effective treatment strategies with radiotherapy-chemotherapy combinations will be needed. Feasibility and toxicity patterns remain to be determined.

[Cerebral intravascular lymphoma during T CD4+ idiopathic lymphopenia syndrome]

BACKGROUND

Intravascular lymphoma is a proliferation of lymphoid cells, usually B cells, in small vessels, predominantly in the nervous system and skin.

CASE REPORT

We report a case of a man with a 3-year history of lymphopenia with no detectable etiology (all viral causes were ruled out) who developed intravascular lymphoma in the cerebral vessels.

DISCUSSION

This case was particular as the patient had idiopathic CD4+ lymphopenia. It points out the probable role of immunodepression in the development of lymphomas, particularly in endovascular localizations.

[Hormone replacement therapy in the prevention of osteoporosis. Evolution of therapeutic methods]

ESTABLISHED FACTS: Many studies have evidenced that hormone replacement therapy can help prevent post-menopausal osteoporosis and osteoporotic fractures in menopaused women. Thanks to recent advances in pharmacology, hormone replacement therapy can now closely mimic ovarian physiology and thus eliminate most of the contraindications related to metabolic disorders. UNRESOLVED QUESTIONS: The need for prolonged treatment to reach optimal efficacy raises the problems of safety and compliance. This is particularly true for the prevention of fractures of the femoral neck which usually occur in older women, suggesting it could be useful to revisit the estrogen strategy. NEW COMPOUNDS: The action of selective estrogen receptor modulators (SERM) depends on the target organ. They have an estrogen agonist effect on bone and lipid metabolism but no such effect on the uterus. SERMs could offer new therapeutic opportunities for the prevention of post-menopausal osteoporosis.

Bone density reduction in various measurement sites in men and women with osteoporotic fractures of spine and hip: the European quantitation of osteoporosis study

We have measured bone mineral density (BMD) using dual X-ray absorptiometry (DXA) of the spine and hip, spinal quantitative computed tomography (QCTspi), and peripheral radial quantitative computed tomography (pQCTrad) in 334 spine and 51 hip fracture patients. The standardized hip and spine BMD for each patient was calculated and compared with the combined reference ranges published previously, each densitometer having been cross-calibrated with the prototype European Spine Phantom (ESPp) or the European Forearm Phantom (EFP). Male and female fracture cases had similar BMD values after adjusting for body size, where appropriate. This suggests that the relationship between bone density (mass per unit volume) and fracture risk is similar between men and women. However, compared with age-matched controls, mean decreases in BMD ranged from 0.78 SD units (women with hip fracture, DXAspi) to 2.57 SD units (men with spine fractures, QCTspi). The proportion of spine and hip fracture patients falling below the cutoff for osteoporosis (T-score <-2.5 SD) proposed by the World Health Organization (WHO) study group varied according to different BMD measurement procedures (range 18-94%). This finding suggests that the WHO definition requires different thresholds when used with non-DXA BMD measurement techniques. Receiver operator characteristic (ROC) analysis was used to compare measurement techniques for their ability to discriminate between cases and controls. Among DXA sites, the proximal femur was preferred when evaluating generalized bone loss, particularly in elderly people. An additional spinal BMD measurement may add clinical value if spine fracture risk assessment has a high priority. Both axial and peripheral QCT techniques performed comparably to DXA in spinal osteoporosis, so investigators and clinicians may use any of the three technologies with similar degrees of confidence for the diagnosis of generalized or site-specific bone loss providing straightforward clinical guidelines are followed.

Coronary heart disease risk factors and menopause: a study in 1684 French women

This study aimed to assess the relationship between menopause and various risk factors for coronary heart diseases (CHD) in a large sample of French women aged 45 65 years. One thousand six hundred and eighty-four consecutive healthy women who received a systematic check-up in our Menopause Unit were included in this study. All the women answered a computer-assisted questionnaire which comprised 156 items, 72 questions being exclusively related to the identification of familial and personal cardio-vascular risk factors. Biological measurements were performed to evaluate lipid-lipoprotein profile and fasting glucose levels. Women, none of whom were treated with hormonal replacement therapy, were classified as postmenopausal according to the date of their last menses and levels of serum FSH and estradiol (n = 1200). Perimenopausal women were further subdivided into two subgroups according to the regularity of their menstrual cycles and FSH levels (early (n = 143) and late (n = 341) perimenopause). 12% (n = 205) of the women were currently receiving lipid-lowering drugs (84.4% postmenopausal vs. 15.6% perimenopausal). When all women were considered, menopause was associated with a higher prevalence of hypertension and hypercholesterolemia (serum total cholesterol level > 250 mg/dl + LDL cholesterol level > 160 mg/dl). This higher prevalence in postmenopausal women was also found when the analysis was restricted to women aged 45 55 years, which rather suggests an effect of menopause than of age. Of the women not receiving hypolipidemic treatments, postmenopausal women had significantly higher serum levels of total cholesterol, LDL , VLDL cholesterol, triglycerides and apolipoprotein B and lower levels of HDL cholesterol than perimenopausal women. Multivariate analysis indicated that these effects were independent of age, body mass index and years since menopause. The prevalence of other metabolic disturbances was much more lower. On average, perimenopausal women had significantly less CHD risk factors than postmenopausal women (P < 0.0001). Fifty-two per cent of the perimenopausal women had none of the risk factors studied as compared with 39% of the postmenopausal women (P < 0.0001). This study shows that menopause was associated with a higher prevalence of risk factors for CHD.

[Polyradicular lesion revealing ankylosing spondylarthritis]

INTRODUCTION

Radicular manifestations of ankylosing spondylitis are rare and observed in the course of long-term ankylosing spondylitis.

EXEGESIS

The case of a young man who presented with bilateral and multiple radicular involvement is reported. Neurological symptoms occur a few weeks before ankylosing spondylitis was diagnosed.

CONCLUSION

This suggests that nerve root lesions might take place during initial stages of the disease. The role of inflammatory changes in the region of the intervertebral foramina is discussed. Disease evolution is marked by relief of neurological disorders in response to anti-inflammatory treatment.

Risk factors for hip fracture in men from southern Europe: the MEDOS study. Mediterranean Osteoporosis Study

The aims of this study were to identify risk factors for hip fracture in men aged 50 years or more. We identified 730 men with hip fracture from 14 centers from Portugal, Spain, France, Italy, Greece and Turkey during the course of a prospective study of hip fracture incidence and 1132 age-stratified controls selected from the neighborhood or population registers. The questionnaire examined aspects of work, physical activity past and present, diseases and drugs, height, weight, indices of co-morbidity and consumption of tobacco, alcohol, calcium, coffee and tea. Significant risk factors identified by univariate analysis included low body mass index (BMI), low sunlight exposure, a low degree of recreational physical activity, low consumption of milk and cheese, and a poor mental score. Co-morbidity including sleep disturbances, loss of weight, impaired mental status and poor appetite were also significant risk factors. Previous stroke with hemiplegia, prior fragility fractures, senile dementia, alcoholism and gastrectomy were associated with significant risk, whereas osteoarthrosis, nephrolithiasis and myocardial infarction were associated with lower risks. Taking medications was not associated with a difference in risk apart from a protective effect with the use of analgesics independent of co-existing osteoarthrosis and an increased risk with the use of anti-epileptic agents. Of the potentially 'reversible' risk factors, BMI, leisure exercise, exposure to sunlight and consumption of tea and alcohol and tobacco remained independent risk factors after multivariate analysis, accounting for 54% of hip fractures. Excluding BMI, 46% of fractures could be explained on the basis of the risk factors sought. Of the remaining factors low exposure to sunlight and decreased physical activity accounted for the highest attributable risks (14% and 9% respectively). The use of risk factors to predict hip fractures had relatively low sensitivity and specificity (59.6% and 61.0% respectively). We conclude that lifestyle factors are associated with significant differences in the risk of hip fracture. Potentially remediable factors including a low degree of physical exercise and a low BMI account for a large component of the total risk.

[Myositis ossificans circumscripta and sequelae of muscular ischemia. 2 cases]

INTRODUCTION

Non-traumatic myositis ossificans circumscripta is a relatively rare, well defined entity. The pathogenic role of ischemia in its development is discussed.

EXEGESIS

We report two cases of myositis ossificans circumscripta that occurred in the hamstring muscle respectively 22 and 35 years after ischemic muscular injury in the same site. Clinical and radiologic informations and follow-up were reexamined, showing that patients are usually young and that the disease is equally distributed between both genders. Though the lesion may develop in various muscle, it is preferentially observed in proximal sites. Most patients have a history of localized pain or tenderness accompanied by swelling of the affected site. Following a 5- to 12-week increase, the soft-tissue mass is less sensitive and better defined. It may also resolve in less than 3 years.

CONCLUSION

Results of X rays, computerized tomography, MR imaging and biopsy are reviewed. Histologically, this lesion main feature is peripheral bone maturation within three areas. Mechanisms (traumatic or not) underlying these lesions are unknown. To our knowledge, only one published case would be comparable to ours. Proliferation followed by change in mesenchymal cells leading to heterotopic ossification must be regarded as a consequence of either ischemia or repeated micro-trauma occurring during muscle shortening.

Measurement of bone mineral density in mother-daughter pairs for evaluating the family influence on bone mass acquisition: a GRIO survey

The relative influence of genetic and environmental determinants on bone mass is still unclear. Using an original multicentric mode of recruitment, based on absorptiometry current practice, the hypothesis of a familial predisposition to low bone mineral content was assessed. The study was based on dual-energy X-ray absorptiometry (DXA) measurements of lumbar and femoral neck bone mineral density (BMD), using daughters of women with a low BMD (case mothers). These BMD values were compared with those of control daughters of women with a normal BMD. Case mothers (n = 72) aged 54.3 +/- 4.8 years were recruited on the basis of a questionnaire and a vertebral Z-score < -2 SD. Their healthy daughters of more than 20 years (n = 77) aged 28.2 +/- 4.9 years had their vertebral and femoral BMD Z-score determined. The control groups were composed of mothers aged 54.1 +/- 4.7 years, paired by age +/- 2 years to the case mothers, and of their daughters of more than 20 years old, aged 27.7 +/- 5.8 years. For daughters, a significant difference was found between the mean vertebral Z-scores (-0.82 +/- 1.08 for cases and 0.01 +/- 1.14 for controls, p < 0.0001). The difference was in the same direction but was not statistically significant for mean femoral Z-scores (-0.58 +/- 1.15 for cases and -0.22 +/- 1.33 for controls, p < 0.073). These findings confirm the hypothesis of a familial predisposition to low BMD.

How hip and whole-body bone mineral density predict hip fracture in elderly women: the EPIDOS Prospective Study

We conducted a population-based cohort study in 7598 white healthy women, aged 75 years and over, recruited from the voting lists. We measured at baseline bone mineral density (BMD g/cm2) of the proximal femur (neck, trochanter and Ward's triangle) and the whole body, as well as fat and lean body mass, by dual-energy X-ray absorptiometry (DXA). One hundred and fifty-four women underwent a hip fracture during an average 2 years follow-up. Each standard deviation decrease in BMD increased the risk of hip fracture adjusted for age, weight and centre by 1.9 (95% CL 1.5, 2.3) for the femoral neck, 2.6 times (2.0, 3.3) for the trochanter, 1.8 times (1.4, 2.2) for Ward's triangle, 1.6 times (1.2, 2.0) for the whole body, and 1.3 times (1.0, 1.5) for the fat mass. The areas under the receiver operating characteristic (ROC) curves were not significantly different between trochanter and femoral neck BMD, whereas ROC curves of femoral neck and trochanter BMD were significantly better than those for Ward's triangle and whole-body BMD. Women who sustained an intertrochanteric fracture were older (84 +/- 4.5 years) than women who had a cervical fracture (81 +/- 4.5 years) and trochanter BMD seemed to be a stronger predictor of intertrochanteric ([RR = 4.5 (3.1, 6.5)] than cervical fractures ([RR = 1.8 (1.5, 2.3]). In very elderly women aged 80 years and more, hip BMD was still a significant predictor of hip fracture but the relative risk was significantly lower than in women younger than 80 years. In the 48% of women who had a femoral neck BMD T-score less than -2.5, the relative risk of hip fracture was increased by 3, and the unadjusted incidence of hip fracture was 16.4 per 1000 woman-years compared with 1.1 in the population with a femoral neck BMD T-score > or = -1.

[MELAS syndrome with pure vascular manifestation?]

Two stroke-like episodes then a grand mal seizure occurred within nine years in a 42-year-old patient. Neuroradiological findings (CT-scan and MRI) led to the diagnosis of incomplete MELAS syndrome. MRI with T2-weighted images (TR: 1000ms; TE: 35ms) showed two small asignal lesions possibly resulting from hemosiderine. Metabolic studies are required to help decide on muscular biopsies. Histological findings are needed for diagnosis of this form of mitochondrial cytopathy with only stroke-like manifestations.

[Vertebral bone loss in perimenopause. Results of a 7-year longitudinal study]

OBJECTIVES

Rapid bone loss after menopause is generally recognized although the exact chronology of the events, particularly in relation to onset of amenorrhea, remains poorly understood. We assessed bone loss in perimenopausal women over a 7-year period.

METHODS

Twenty-one women with an uneventful past history were enrolled before menopause and followed until menopause had been completely established. Vertebral bone density was measured by biphotonic absorptiometry annually over two 2-year periods. Individual variations in bone density were calculated according to onset of menopause.

RESULTS

Bone loss in the vertebral body increased during the two years preceding menopause (-1.6 +/- 1.5% per year), reached a peak during the first three post-menopausal years (-2.4 +/- 1.6% per year), and then fell off (-1.2 +/- 1.4% per year).

CONCLUSION

Bone loss was independent of calcium intake and appeared to be related mainly to characteristic hormone changes during the perimenopausal period. These findings raise the question as to the need and means of prevention.

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.

Effect of menopause on femoral and vertebral bone loss

The aim of this study was to investigate the effect of menopause on bone loss in the proximal femur and the lumbar spine. The rates of change in bone mineral density (BMD) were measured longitudinally by dual X-ray absorptiometry (DXA) at the femoral neck (FN), Ward's triangle (WT), and trochanter (TR) together with the lumbar spine in 81 healthy postmenopausal women (45-65 years of age) who had passed a natural menopause, 6 months to 12 years before. A significant correlation between the rate of change and interval since menopause was evidenced. The best fit of the data was a binomial function of interval since menopause at the spine, FN, and WT and a simple linear regression at TR level. At each skeletal site, the rate of bone loss (mean +/- SD) was significantly different (p<0.05) and twice as high in women who were between 6 months and 2 years postmenopausal at enrollment (FN, -1.82 +/- 1.1%; WT, -2.43 +/- 1.7%; TR, -1.12 +/- 1.7%) than in those who were beyond 5 years of menopause (FN, -0.48 +/- 0.8%; WT, -0.68 +/- 2.1% TR, 0.41 +/- 1.2%). A poor correlation (r = 0.39 - 0.42, p<0.001) was found between the rate of vertebral and that of femoral postmenopausal bone loss. This study demonstrates that menopause is associated with a rapid and transient bone loss in BMD of the proximal femur, which declines with time after 3 years. These data suggest that therapy should be initiated as early as possible after menopause to prevent bone loss.

[Hormone replacement therapy and early and late prevention of postmenopausal osteoporosis]

Osteoporosis is one of the main features of the ageing process and the cost of health care for osteoporosis-related fractures and their complications is a major incentive for prevention, particularly in developed countries with a continuously ageing population. The earliest strategies for prevention in menopaused women were based on the anti-osteoclastic effect of hormone replacement therapy. Several epidemiological studies have provided proof of its efficacy showing that in treated populations, there is a significant reduction in osteoporosis-related fractures of about 50%, whatever the site of fracture. Although the effects of hormone replacement therapy in the prevention of post-menopausal osteoporosis have been well established, three problems remain. First, what is the degree of efficacy if replacement therapy is started late? Second, what is the effect in patients who have already suffered an osteoporotic fracture? Third, and most importantly, what is the optimal duration of treatment for effective prevention in a given population particularly at risk of hip fracture? These questions suggest new strategies for preventive hormone replacement are needed.