Bone densitometry in premenopausal women: synthesis and review

Osteoporotic Fractures: Diagnosis, Evaluation, and Significance From the International Working Group on DXA Best Practices

Osteoporotic fractures, also known as fragility fractures, are reflective of compromised bone strength and are associated with significant morbidity and mortality. Such fractures may be clinically silent, and others may present clinically with pain and deformity at the time of the injury. Unfortunately, and even at the time of detection, most individuals sustaining fragility fractures are not identified as having underlying metabolic bone disease and are not evaluated or treated to reduce the incidence of future fractures. A multidisciplinary international working group with representation from international societies dedicated to advancing the care of patients with metabolic bone disease has developed best practice recommendations for the diagnosis and evaluation of individuals with fragility fractures. A comprehensive narrative review was conducted to identify key articles on fragility fractures and their impact on the incidence of further fractures, morbidity, and mortality. This document represents consensus among the supporting societies and harmonizes best practice recommendations consistent with advances in research. A fragility fracture in an adult is an important predictor of future fractures and requires further evaluation and treatment of the underlying osteoporosis. It is important to recognize that most fragility fractures occur in patients with bone mineral density T scores higher than -2.5, and these fractures confirm the presence of skeletal fragility even in the presence of a well-maintained bone mineral density. Fragility fractures require further evaluation with exclusion of contributing factors for osteoporosis and assessment of clinical risk factors for fracture followed by appropriate pharmacological intervention designed to reduce the risk of future fracture. Because most low-trauma vertebral fractures do not present with pain, dedicated vertebral imaging and review of past imaging is useful in identifying fractures in patients at high risk for vertebral fractures. Given the importance of fractures in confirming skeletal fragility and predicting future events, it is recommended that an established classification system be used for fracture identification and reporting.

Bone Mineral Density and Bone Turnover Marker in a Subclinical Thyrotoxic State in Young Premenopausal Women

BACKGROUND

Subclinical thyrotoxicosis (SCH) is characterized by normal serum thyroid hormone levels and low thyrotropin levels. The impact of this condition on the skeletal system may vary depending on its cause, yet the relationship is not fully comprehended in premenopausal women. Studies are scarce about its effects on bone health in our population.

OBJECTIVES

This study aims to evaluate the bone mineral density (BMD) and bone turnover markers in premenopausal women with SCH and determine if any differences exist based on the condition's etiology.

METHODS

A cross-sectional study was conducted at Ramaiah Medical College involving 36 participants for one year and six months after approval from the Ethics Committee. The carboxy-terminal telopeptide of type I collagen in blood and BMD were measured at the lumbar vertebrae (L1-L4) and femoral neck by dual-energy x-ray absorptiometry (Hologic v 2.0, Hologic, Massachusetts, U.S.). Statistical analysis was done using IBM SPSS Statistics for Windows, Version 20 (Released 2011; IBM Corp., Armonk, New York, United States).  Results: The mean age of the study population was 35.2 ± 7.2 years. The etiology was Graves' disease [n=11 (33.3%)], iatrogenic [n=14(38.8%)], toxic adenoma [n=6 (15.1%)], and multi-nodular goiter [n=5 (15.1%)]. The mean BMI was 23.5 ± 3.8 kg/m2, and the mean levels of corrected calcium, phosphorus, and 25 hydroxy-vitamin D were 9.12 ± 0.25 mg/dl, 2.95 ± 0.34 mg/dl, and 29.4 ± 6.4 ng/ml, respectively. The mean BMD at hip and spine was 0.81 ±0.16 g/cm2 and 0.92±0.08 g/cm2 respectively. The mean Z-score was (-0.02 ± 0.8) and (-0.92± 0.08) at the hip and spine. No significant difference was observed in the BMD at the hip (p = 0.14) or spine (p = 0.44) between the endogenous and exogenous subclinical thyrotoxic subgroups. At the same time, the carboxy-terminal telopeptide of type I collagen was significantly different between the two groups (p<0.05).

CONCLUSION

In our cross-sectional study of premenopausal women with SCH, BMD at the hip or spine as measured by dual-energy X-ray absorptiometry did not reveal any significant reduction. The subclinical thyrotoxic state may not have an adverse effect on bone health in premenopausal females with sufficient levels of serum 25-hydroxy-vitamin D in the short term.

The Role of Soy Isoflavones in the Prevention of Bone Loss in Postmenopausal Women: A Systematic Review with Meta-Analysis of Randomized Controlled Trials

The aim of the report was to determine the effects of soy isoflavones on lumbar spine, femoral neck, and total hip bone mineral density (BMD) in menopausal women. MEDLINE (PubMed), EMBASE, and Cochrane Library databases were searched for articles published in English during 1995–2019. Studies were identified and reviewed for inclusion and exclusion eligibility. Weighted mean differences (WMD) were calculated for each study and were pooled by using the random effects model. Eighteen randomized controlled trials were selected for meta-analysis. Different types of soy phytoestrogens, i.e., genistein extracts, soy isoflavones extracts, soy protein isolate, and foods containing diverse amounts of isoflavones were used in the studies. The analysis showed that daily intake of 106 (range, 40–300) mg of isoflavones for 6–24 months moderately but statistically significantly positively affects BMD, compared with controls: lumbar spine WMD = 1.63 (95% CI: 0.51 to 2.75)%, p = 0004; femoral neck WMD = 1.87 (95% CI: 0.14 to 3.60)%, p = 0.034; and total hip WMD = 0.39 (95% CI: 0.08 to 0.69)%, p = 0.013. Subgroups analyses indicated that the varying effects of isoflavones on BMD across the trials might be associated with intervention duration, racial diversity (Caucasian, Asian), time after menopause, form of supplements (especially genistein), and dose of isoflavones. Our review and meta-analysis suggest that soy isoflavones are effective in slowing down bone loss after menopause.

Corticosteroid use in chronic dermatologic disorders and osteoporosis

Glucocorticoid-induced osteoporosis (GIOP) is a frequently encountered and serious side effect of glucocorticoid use. Bone loss leading to an increased risk for fracture occurs early in the use of glucocorticoids, yet patients at risk for this complication are often undertreated. All physicians prescribing glucocorticoids should therefore be familiar with a basic approach to anticipating and preventing GIOP when starting patients on glucocorticoid therapy. This manuscript and its case vignettes are designed to help dermatologists assess and manage bone health to prevent GIOP in patients receiving glucocorticoid therapy.

Osteoporosis in Premenopausal Women: A Clinical Narrative Review by the ECTS and the IOF

CONTEXT

Consensus regarding diagnosis and management of osteoporosis in premenopausal women (PW) is still lacking due to few studies carried out in this population.

DESIGN

The European Calcified Tissue Society and the International Osteoporosis Foundation convened a working group to produce an updated review of literature published after 2017 on this topic.

RESULTS

Fragility fractures in PW are rare and mostly due to secondary osteoporosis (ie, in presence of an underlying disease such as hormonal, inflammatory, or digestive disorders). In absence of another disorder, low bone mineral density (BMD) together with fragility fractures qualifies as idiopathic osteoporosis. In contrast, low BMD alone does not necessarily represent osteoporosis in absence of bone microarchitectural abnormalities. BMD increases in PW with osteoporosis when the underlying disease is treated. For example, in celiac disease, an increase of 9% in radius trabecular volumetric density was achieved after 1 year of gluten-free diet, while anti-tumor necrosis factor alpha improved BMD in PW with inflammatory bowel diseases. In amenorrhea, including anorexia nervosa, appropriately delivered estrogen replacement therapy can also improve BMD. Alternatively, antiresorptive or anabolic therapy has been shown to improve BMD in a variety of conditions, the range of improvement (3%-16%) depending on skeletal site and the nature of the secondary cause. No studies were powered to demonstrate fracture reduction. The effects of bisphosphonates in childbearing women have been scantly studied and caution is needed.

CONCLUSION

The majority of PW with osteoporosis have an underlying disease. Specific therapy of these diseases, as well as antiresorptive and anabolic drugs, improve BMD, but without evidence of fracture reduction.

Premenopausal Osteoporosis

Most premenopausal women with low trauma fracture(s) or low bone mineral density have a secondary cause of osteoporosis or bone loss. Where possible, treatment of the underlying cause should be the focus of management. Premenopausal women with an ongoing cause of bone loss and those who have had, or continue to have, low trauma fractures may require pharmacologic intervention. Clinical trials provide evidence of benefits of bisphosphonates and teriparatide for bone mineral density in several types of premenopausal osteoporosis, but studies are small and do not provide evidence regarding fracture risk reduction.

Glucocorticoid-Induced Osteoporosis

Glucocorticoids are widely used to treat several diseases; however, one of their major consequences is a deleterious effect on bone that may lead to glucocorticoid-induced osteoporosis. Fractures may begin to occur within 3 months of commencing oral glucocorticoid therapy, and may even occur in patients receiving low doses. The good news is that with effective management, bone loss and fractures can be prevented or greatly reduced in patients receiving glucocorticoids. Despite clear practice guidelines, glucocorticoid-induced osteoporosis often goes undiagnosed and untreated in many patients. In this article, a current overview of glucocorticoid-induced osteoporosis is provided, including how to recognize, prevent and treat osteoporosis in pre- and postmenopausal women receiving glucocorticoid therapy.

Evaluation and management of the premenopausal woman with low BMD

Interpretation of bone mineral density (BMD) results in premenopausal women is particularly challenging, since the relationship between BMD and fracture risk is not the same as for postmenopausal women. In most cases, Z scores rather than T scores should be used to define "low BMD" in premenopausal women. The finding of low BMD in a premenopausal woman should prompt thorough evaluation for secondary causes of bone loss. If a secondary cause is found, management should focus on treatment of this condition. In a few cases where the secondary cause cannot be eliminated, treatment with a bone active agent to prevent bone loss should be considered. In women with no fractures and no known secondary cause, low BMD is associated with microarchitectural defects similar to young women with fractures; however, no longitudinal data are available to allow use of BMD to predict fracture risk. BMD is likely to be stable in these women with isolated low BMD, and pharmacologic therapy is rarely necessary. Assessment of markers of bone turnover and follow-up bone density measurements can help to identify those with an ongoing process of bone loss that may indicate a higher risk for fracture, and possible need for pharmacologic intervention.

Skeletal manifestations of treatment of breast cancer on premenopausal women

With increasing use of screening mammography and more effective adjuvant systemic therapies, the majority of women diagnosed with early stage breast cancer will be long-term survivors and experience personal cures. Among the common side effects of adjuvant therapies is treatment-related bone loss, primarily as a result of estrogen deprivation. Whereas this occurs in both postmenopausal and premenopausal women, this brief review will focus on pre- or perimenopausal women when initially diagnosed with breast cancer. An important distinction is between those women who retain ovarian function despite cancer or preventative treatments and the more common situation of premenopausal women who as result of cancer treatments undergo ovarian failure or early menopause. Some women with treatment-related ovarian failure will have sufficient treatment-related bone loss to be at increased risks of subsequent nontraumatic fractures and/or osteoporosis and will be candidates for antiresorptive treatments. The noncancer treatment risk factors, screening and treatments for the management of osteopenia and osteoporosis are generally the same in postmenopausal women with and without breast cancer. However, premenopausal women with relatively rapid onset of treatment-related ovarian failure and bone loss pose several challenges. Awareness of treatment-related bone loss and risks of subsequent osteoporosis is a high priority in an ever-increasing population of breast cancer survivors.

Central QCT reveals lower volumetric BMD and stiffness in premenopausal women with idiopathic osteoporosis, regardless of fracture history

CONTEXT

Idiopathic osteoporosis (IOP) affects otherwise healthy young individuals with intact gonadal function and no secondary cause of bone fragility. In premenopausal women with IOP, a low trauma fracture is evidence of impaired bone quality and strength. The extent to which low bone mineral density (BMD) by dual-energy x-ray absorptiometry (DXA) reflects low volumetric BMD, bone microstructure, and strength is uncertain in the absence of low trauma fracture.

OBJECTIVE

The objective of the study was to compare three-dimensional volumetric BMD and bone stiffness in premenopausal women with IOP based on fracture history, those with idiopathic low BMD (Z score ≤ -2.0) and no low trauma fracture, and normal age-matched controls.

DESIGN

We measured volumetric BMD and bone geometry by central quantitative computed tomography (cQCT) scans of the spine and hip and estimated bone stiffness by finite element analysis of cQCT data sets in 32 premenopausal women with IOP, 12 with idiopathic low BMD, and 34 controls.

RESULTS

Subjects had comparable decreases in total and trabecular volumetric BMD, cortical thickness, and whole-bone stiffness compared with controls, regardless of fracture history. These differences remained significant after controlling for age, body mass index, and bone size. The positive predictive values of a DXA Z score of -2.0 or less for a cQCT volumetric BMD Z score of -2.0 or less were 95% at the lumbar spine, 90% at the total hip, and 86% at the femoral neck.

CONCLUSION

Women with idiopathic low BMD alone and those with low trauma fractures had comparable deficits in bone mass, structure, and stiffness. Low areal BMD by DXA is fairly accurate for predicting low volumetric BMD by cQCT. These results are consistent with three-dimensional bone imaging at the iliac crest, radius, and tibia in premenopausal IOP and suggest that the term osteoporosis may be appropriate in women with Z scores below -2.0, whether or not there is a history of fracture.

Bone mineral density assessment in premenopausal women

In the absence of fragility fractures, low bone mineral density may reflect attainment of a lower peak bone mass in comparison with the young adult mean value. It is necessary to distinguish between low peak bone mass and a systemic disorder resulting in low bone mineral density and skeletal fragility. Low peak bone mass in the absence of fragility fracture or progressive bone loss may not require pharmacological intervention. However, systemic disorders contributing to bone loss do require diagnosis and intervention. Common causes of low bone density in premenopausal women include ovulatory disturbances and low body weight. Other diseases, conditions or medications may also contribute to bone loss and these should be identified and treated if present. Fracture risk is reduced by lifestyle changes and pharmacological intervention in those with glucocorticoid-induced bone loss. Discontinuing depo medroxyprogesterone acetate use has been associated with improvements in bone mineral density. Bone mineral density alone is insufficient for the diagnosis of osteoporosis in premenopausal women in the absence of fragility fractures. Bone mineral density testing should only be performed in premenopausal women in the presence of approved indications.

Influence of aging and menopause in the origin of the superior semicircular canal dehiscence

OBJECTIVE

Determine if aging and menopause, known to be associated with bone resortion, also are associated with superior semicircular canal dehiscence.

DESIGN

Observational study.

SETTING

Study conducted in 3 tertiary Spanish hospitals.

PATIENTS

Nonselected consecutive patients of all ages.

INTERVENTIONS

Thin-section multi-detector row computed tomographic scan of the temporal bones.

MAIN OUTCOME MEASURE

The minimum thickness of the bone covering the roof of the superior semicircular canal (SSC) measured in each temporal bone. The outcome was studied both as a continuous and as a dichotomous variable: thin (<0.6 mm) and normal (≥ 0.6 mm).

RESULTS

Five hundred eighty-two ears of 312 patients were included in the study. Fifty-five percent of the sample were women. Patient's age ranged from 2 to 88 years. A 40-year age difference between ears was associated with a decreased thickness of bone covering the SSC of 0.10 mm, which is 10% of the average thickness of such bone. The thickness of the bone overlying the SSC of subjects younger than 45 years was an average of 1.14 mm (SD, 0.52 mm), whereas that of the subjects older than 45 years was equal to 1.02 mm (SD, 0.45 mm; p = 0.006). The percentage of ears with thin bone coverage of SSC was 7.1% in subjects younger than 45 years and 13.8% in those older than 45 years (p = 0.013).

CONCLUSION

Our data support the hypothesis that there is a slight osteopenia of the roof of the superior semicircular canal associated with aging, and this effect seems to be more pronounced in menopausal women.

Abnormal bone microarchitecture and evidence of osteoblast dysfunction in premenopausal women with idiopathic osteoporosis

CONTEXT

Idiopathic osteoporosis (IOP) in premenopausal women is an uncommon disorder of uncertain pathogenesis in which fragility fractures occur in otherwise healthy women with intact gonadal function. It is unclear whether women with idiopathic low bone mineral density and no history of fragility fractures have osteoporosis.

OBJECTIVE

The objective of the study was to elucidate the microarchitectural and remodeling features of premenopausal women with IOP.

DESIGN

We performed transiliac biopsies after tetracycline labeling in 104 women: 45 with fragility fractures (IOP), 19 with idiopathic low bone mineral density (Z score ≤-2.0) and 40 controls. Biopsies were analyzed by two-dimensional quantitative histomorphometry and three-dimensional microcomputed tomography. Bone stiffness was estimated using finite element analysis.

RESULTS

Compared with controls, affected women had thinner cortices; fewer, thinner, more widely separated, and heterogeneously distributed trabeculae; reduced stiffness; and lower osteoid width and mean wall width. All parameters were indistinguishable between women with IOP and idiopathic low bone mineral density. Although there were no group differences in dynamic histomorphometric remodeling parameters, serum calciotropic hormones, bone turnover markers, or IGF-I, subjects in the lowest tertile of bone formation rate had significantly lower osteoid and wall width, more severely disrupted microarchitecture, lower stiffness, and higher serum IGF-I than those in the upper two tertiles, suggesting that women with low turnover IOP have osteoblast dysfunction with resistance to IGF-I. Subjects with high bone turnover had significantly higher serum 1,25 dihydroxyvitamin D levels and a nonsignificant trend toward higher serum PTH and urinary calcium excretion.

CONCLUSIONS

These results suggest that the diagnosis of IOP should not require a history of fracture. Women with IOP may have high, normal or low bone turnover; those with low bone turnover have the most marked deficits in microarchitecture and stiffness. These results also suggest that the pathogenesis of idiopathic osteoporosis is heterogeneous and may differ according to remodeling activity.

Updated recommendations for the diagnosis and management of osteoporosis: a local perspective

Postmenopausal osteoporosis and osteoporosis in elderly men are major health problems, with a significant medical and economic burden. Although osteopenia and osteoporosis are more common locally than in the West, fracture rates are generally less than in Western countries. Vitamin D deficiency is common in the region and contributes adversely to bone health. Vitamin D deficiency should be suspected and treated in all subjects with ostopenia or osteoporosis. The use of risk factors to determine fracture risk has been adopted by the World Health Organization and many international societies. Absolute fracture risk methodology improves the use of resources by targeting subjects at higher risk of fractures for screening and management. The King Faisal Specialist Hospital Osteoporosis Working Group recommends screening for women 65 years and older and for men 70 years and older. Younger subjects with clinical risk factors and persons with clinical evidence of osteoporosis or diseases leading to osteoporosis should also be screened. These guidelines provide recommendations for treatment for postmenopausal women and men older than 50 years presenting with osteoporotic fractures for persons having osteoporosis-after excluding secondary causes-or for persons having low bone mass and a high risk for fracture. The Working Group has suggested an algorithm to use at King Faisal Specialist Hospital that is based on the availability, cost, and level of evidence of various therapeutic modalities. Adequate calcium and vitamin D supplement are recommended for all. Weekly alendronate (in the absence of contraindications) is recommended as first-line therapy. Alternatives to alendronate are raloxifene or strontium ranelate. Second-line therapies are zoledronic acid intravenously once yearly, when oral therapy is not feasible or complicated by side effects, or teriparatide in established osteoporosis with fractures.

Effective risk assessment tools for osteoporosis in the Indian menopausal female

OBJECTIVES

This study was designed to assess the effectiveness of self-administered osteoporosis risk score sheet, body mass index (BMI), and bone mineral density (BMD) (ultrasound) in screening females with low bone mass, and how the results of the tools correlate with each other.

MATERIALS AND METHODS

The study was conducted on 536 postmenopausal women, who attended public awareness camps on Midlife Women Health held at the Menopause Research Unit, MGMCH, Sitapura, Jaipur. At these camps, in addition to several informational sessions on issues related to menopause, ultrasonic measurement of BMD was conducted on each participant. A broad questionnaire to identify midlife health problems was developed, and osteoporosis specific score sheet was designed to be self-administered. Patients were required to complete the osteoporosis specific risk score sheet and women health questionnaire (WHQ). BMI was determined. Statistical analysis was carried out to find the correlation between various variables. Sensitivity and specificity of the each risk score ascertained and cutoff risk score for identifying osteopenia was derived by comparing area under curve of each risk score on drawing receiver operational curve (ROC).

RESULTS

Sensitivity of risk score system was calculated to be 78.33% with 95% confidence interval being 73.24-82.86% and specificity was 27.12% with 95% confidence interval being 21.56-33.27%, keeping the cutoff point at nine. There was statistically significant inverse relationship between risk score and BMD values with Pearson correlation coefficient of (-) 0.22 and positive relationship between BMD and BMI with correlation coefficient of 0.192.

CONCLUSION

By noting down the risk factors and BMI, we can screen out the women who require further evaluation and management, thus, it is an effective tool, particularly in developing countries like India, where most of the patients cannot afford expensive DEXA scans, although considered as the gold standard for BMD assessment. With the help of such scoring systems, health resources can be judiciously utilized.

Bone microarchitecture and stiffness in premenopausal women with idiopathic osteoporosis

CONTEXT

Idiopathic osteoporosis (IOP) is an uncommon disorder in which low areal bone mineral density (aBMD) and/or fractures occur in otherwise healthy premenopausal women.

OBJECTIVES

Our objectives were to characterize bone mass, microarchitecture, and trabecular bone stiffness in premenopausal IOP and to determine whether women with low aBMD who have never fractured have abnormal microarchitecture and stiffness.

DESIGN, SETTING, AND PATIENTS

We conducted a prospective cohort study of 27 normal controls and 31 women with IOP defined by low trauma fracture (n = 21) or low BMD (Z score <or=-2.0; n = 10).

MAIN OUTCOME MEASURES

We assessed aBMD by dual-energy x-ray absorptiometry; volumetric BMD and cortical and trabecular microarchitecture of the radius and tibia by high-resolution (82 microm) peripheral quantitative computed tomography; and trabecular bone stiffness (elastic moduli), estimated by micro-finite element analysis.

RESULTS

Fracture subjects did not differ from controls by age or body mass index, which was lower in low-BMD subjects than controls. Fracture subjects also had lower aBMD than controls at all sites (P < 0.05-0.0001). Bone size was similar in controls and fracture subjects but 10.6% smaller in low-BMD subjects (P < 0.05). Every trabecular parameter in both fracture and low-BMD groups was markedly worse than controls (P < 0.01-0.0001). Cortical thickness was significantly lower in both fracture and low-BMD groups at the tibia but not radius. Bone stiffness estimated by micro-finite element analysis was comparably reduced in low-BMD and fracture groups.

CONCLUSION

Premenopausal women with IOP had marked trabecular microarchitectural deterioration at the radius and tibia. Cortical parameters were affected only at the tibia. Although they had not fractured, microarchitectural deterioration was similar in IOP women with low BMD and those with fractures.

Clinical characteristics and medication use among premenopausal women with osteoporosis and low BMD: the experience of an osteoporosis referral center

AIMS

Osteoporosis is uncommon in premenopausal women, and most cases have a secondary cause. Women with osteoporosis and no known secondary cause are said to have idiopathic osteoporosis (IOP). We aimed to estimate the proportion of premenopausal women seen in our referral center with IOP as opposed to secondary osteoporosis, to describe their clinical characteristics, to compare women with a low-trauma fracture history with those with low bone mineral density (BMD) alone, and to estimate the frequency of bisphosphonate use.

METHODS

We reviewed medical records from all premenopausal women evaluated for osteoporosis or low BMD in our center during 2005. We included premenopausal women diagnosed on the basis of low-trauma fracture, low BMD or both (Z score < or= -2.0 or T score < or = -2.5), or both.

RESULTS

Among these patients (n = 61; mean age 37 +/- 8), 57 (93%) were Caucasian, 34 (57%) had a family history of osteoporosis, and 26 (43%) had used bisphosphonates. The most common secondary causes were amenorrhea (34%, n = 21), anorexia nervosa (16%, n = 10), and glucocorticoid exposure (13%, n = 8). After exclusion of secondary causes, 39% (24 of 61) of the entire group and 48% (14 of 29) of the fracture group were thought to have IOP. Women with a known secondary cause had lower BMD Z scores at the spine and hip than those with IOP. Women with low BMD and no fractures had shorter stature and weighed less than those with fractures, but overall differences between the groups were not statistically significant. Bisphosphonates had been prescribed for 38% (11 of 29) of women with a fracture history and 47% (15 of 32) of women with low BMD and no fractures.

CONCLUSIONS

Our findings suggest that IOP is common among premenopausal women with osteoporosis or low BMD evaluated at a referral center. The smaller stature of women diagnosed only on the basis of BMD criteria raises the question of whether their areal BMD measurements are spuriously low because of smaller bone size. The high proportion of premenopausal women who had been prescribed oral bisphosphonates for low BMD measurements is of concern, as such women are likely to be at low short-term risk of fracture, and a more conservative approach to therapy is preferable in this group.

Quantitative ultrasound in relation to risk factors for low bone mineral density in South African pre-menopausal women

SUMMARY: The study describes the association between risk factors and quantitative ultrasound bone measures in black and mixed-race pre-menopausal South African women. Despite some differences between the two study groups, the findings generally lend support to the use of ultrasound for epidemiological studies of bone mass in resource-limited settings. INTRODUCTION: Quantitative ultrasound at the calcaneus is a convenient and inexpensive method of estimating bone strength well suited to community-based research in countries with limited resources. This study determines, in a large sample of pre-menopausal South African women, whether characteristics associated with quantitative ultrasound measures are similar to those shown to be associated with bone mineral density as measured by dual X-ray absorptiometry. METHODS: This cross-sectional study included 3,493 women (1,598 black and 1,895 mixed race), aged 18-44 living in Cape Town. Study nurses administered structured interviews on reproductive history, lifestyle factors, and measured height and weight. Calcaneus quantitative ultrasound measurements were obtained using the Sahara device. Adjusted means of ultrasound measures according to categories of risk factors were obtained using multivariable regression analysis. RESULTS: Associations between quantitative ultrasound measures and age, body mass index, age at menarche, parity, and primary school physical activity were similar to those known for bone mineral density as measured by dual X-ray absorptiometry. There were no clear associations between quantitative ultrasound measures and educational level, alcohol use, cigarette smoking, and current calcium intake. CONCLUSION: The data give qualified support to the use of quantitative ultrasound as an epidemiological tool in large studies of bone strength in pre-menopausal women.

Effect of Dietary Induced Metabolic Acidosis on Bone Mineral Acquisition in 2-8 Month Old Lambs

Dietary induced metabolic acidosis (MA) results in a negative calcium balance in normal animals. In order to maintain acid-base homeostasis the body's primary base buffer source calcium is mobilized from bone. This study examined the impact of dietary induced MA on bone in an adolescent ovine model. We hypothesized that a MA diet would reduce bone mineral density (BMD) in growing sheep.

Twelve 2 month old lambs of mixed sex were divided into 2 groups. The MA group consumed a ration that was relatively acidogenic compared to the control diet (CD) for 6 months. DXA was performed on days 0 and 180. Arterial blood samples were evaluated on days 0, 30, 120, 150 and 180 for pH, pCO2, pO2, HCT, Na, K, ionized Ca, HCO3–, TCO2, base excess (BE), and O2 saturation. Histomorphometry of the femoral diaphysis was performed from samples harvested at 180 days. Statistical analysis consisted of a 2-way ANOVA for sex and diet with repeated measures for bone mineral content (BMC) and blood parameters, a 2-way ANOVA for one time measurements at 180 d including BMD of the whole body, radii, femora and lumbar vertebrae, and 1-way ANOVA to compare histomorphometric measurements.

Percent increase from baseline for BMD of the whole body was 1.8x greater in the CD group than the MA group. BMC of the whole body and lumbar vertebrae was significantly less in the MA group. Lumbar BMD on day 180 was 30% less in the MA group. Cortical bone was less affected. Radii and femora BMD was 18% and 21% less, respectively, in the MA group than in the CD group. MA treatment significantly decreased pH, HCT, iCa, HCO3–, TCO2 and BE. However, no blood parameters were outside the normal range for this species. Histomorphometry revealed significantly decreased cortical area and thickness and increased mineral apposition rate and endosteal active surface length in the femoral cortex of the MA group compared to the CD group.

This study demonstrated a well compensated dietary induced MA that resulted in a significant decrease in bone mineral acquisition in juvenile sheep. Diets that induce MA may have a profound impact on lowering peak BMD in adolescents and therefore predispose individuals to osteoporosis later in life.

Follicle-stimulating hormone does not directly regulate bone mass in human beings: evidence from nature

OBJECTIVE

To evaluate the effect of FSH levels in the development of human osteoporosis.

DESIGN

Case-series study.

SETTING

Gynecology department in a teaching hospital.

PATIENT(S)

A total of 8 women diagnosed with Kallman syndrome (KS) were compared with 11 with Turner syndrome and 11 with pure gonadal dysgenesia (GD, karyotype 46,XX).

INTERVENTION(S)

We assessed the pituitary-gonadal axis, bone turnover markers, bone mass, and patient characteristics.

MAIN OUTCOME MEASURE(S)

Bone mineral density as assessed by dual-energy X-ray absorptiometry, plasma FSH, LH, E(2), osteocalcin (BGP), and urinary type I collagen cross-linked N-telopeptide. Other biochemical markers included 25-hydroxyvitamin D, as well as parathyroid hormone and urine concentration of calcium and creatinine.

RESULT(S)

In girls with Turner syndrome and GD, FSH (64.03 +/- 29.2 and 90.08 +/- 22.41 mIU/mL, respectively) and LH (45.29 +/- 11.90 and 48.83 +/- 12.44 mIU/mL, respectively) levels were significantly higher compared with those observed in girls with KS (FSH: 1.87 +/- 0.64 and LH: 1.02 +/- 0.57), whereas no differences were detected in E(2) or bone marker levels. Bone mineral density correlated positively with FSH levels but not with E(2); however, after adjusting for previous growth-hormone therapy, these differences were not found. In addition, bone mineral density in spine and total hip was significantly lower in patients with KS.

CONCLUSION(S)

Follicle-stimulating hormone does not appear to have a major role in the development of bone loss in young women with primary amenorrhea.

Osteoporosis, schizophrenia and antipsychotics: the need for a comprehensive multifactorial evaluation

Osteoporosis is recognised as a major public health issue leading to bone fractures, pain and disability. Awareness of an elevated risk of osteoporosis in individuals with schizophrenia is increasing. An accelerated decrease in bone mineral density (BMD) in patients with schizophrenia may be disease related or drug induced. A drug-induced decrease in BMD has been attributed mostly to hyperprolactinaemia and its consequences. However, as demonstrated in this review, decreased BMD and osteoporosis are multifactorial processes, and abnormal bone structure and functions are not limited to BMD. Multiple dynamic processes may lead to impairment of bone homeostasis and eventually to bone abnormalities. Many of these processes may be abnormal in treated as well as untreated patients with schizophrenia. Despite many publications, the epidemiology of abnormal bone structure, mineralisation and dynamics in patients with schizophrenia is still not fully determined. Comprehensive studies of bone dynamics in individuals with first-episode schizophrenia, as well as in patients treated with various current medications, are needed in order to characterise the problem(s) and then to develop relevant treatment and prevention strategies.

Beneficial effect of pretreatment and treatment continuation with risedronate and vitamin K2 on cancellous bone loss after ovariectomy in rats: a bone histomorphometry study

The purpose of the present study was to examine the effect of pretreatment with risedronate and/or vitamin K2 and treatment continuation with reduced dosing frequency of the drugs on the early cancellous bone loss induced by ovariectomy (OVX) in rats. Eighty female Sprague-Dawley rats, 4 mo of age, were randomized by the stratified weight method into eight groups (n= 10 in each group); rats subjected to OVX, but not sham-operated rats, were treated with vehicle, risedronate, vitamin K2 (menatetrenone), or risedronate+vitamin K2 for 4 wk before the surgery, and the treatment was either discontinued (pretreatment groups) or continued after the surgery (treatment continuation groups) for 2 wk. Sham-operated rats (controls) were treated with the vehicle throughout the experimental period. During the 4 wk prior to the surgery (pretreatment), risedronate and vitamin K2 were administered five times a week either subcutaneously at a dose of 2.5 microg/kg body weight (risedronate) or orally at the dose of 30 mg/kg body weight (vitamin K2). During the 2 wk after the surgery (treatment continuation), the dosing frequency of the drugs was reduced to twice a week. Risedronate and vitamin K2 had an anti-resorptive effect on the bone. Pretreatment with risedronate alone, but not vitamin K2 alone, prevented the loss of the cancellous bone volume/total volume (BV/TV) of the proximal tibial metaphysis after OVX. Treatment continuation with vitamin K2 alone prevented the loss of the cancellous BV/TV after OVX, while treatment continuation with risedronate alone increased the cancellous BV/TV to beyond the values in controls. Pretreatment with risedronate+vitamin K2 had a more beneficial effect in increasing the cancellous bone mass than pretreatment with risedronate alone. Treatment continuation with risedronate and/or vitamin K_ appeared to have a more beneficial effect in increasing the cancellous bone mass than the respective pretreatment. Neither the total tissue area nor the cortical area of the tibial diaphysis was affected by any treatment. The present study demonstrated that pretreatment with risedronate had a beneficial effect on the early cancellous bone loss after OVX in rats, with a more beneficial effect when combined with vitamin K2. Moreover, even though the dosing frequency of the drugs was reduced after OVX, treatment continuation appeared to be more beneficial than pretreatment for increasing the cancellous bone mass.

Preferred skeletal site for osteoporosis screening in high-risk populations

OBJECTIVES

The current World Health Organization (WHO) definition of osteoporosis, which is based on densitometry of lumbar and femoral regions, is extensively used for decision-making in clinical practice. Discordance in diagnosis of osteoporosis using this definition is a known phenomenon. The aim of this study was to evaluate the impact of such discordance and to assess the diagnostic value of using one skeletal site for screening purposes as opposed to the two sites required in the WHO criteria.

STUDY DESIGN

Data was collected from 4188 individuals (3848 female); mean age=53.4 years (standard deviation 11.8) referred to a community-based outpatient osteoporosis testing centre in Tehran, Iran.

METHODS

Dual-energy X-ray absorptiometry (DXA) was performed on L1-L4 lumbar spine and total hip for all cases. The DXA results were categorized according to WHO criteria. Sensitivity for each site was calculated as number of cases with T-score < -2.5 at that site divided by the total number of cases with T-score < -2.5 at any site.

RESULTS

Prevalence of osteoporosis diagnosis using lumbar DXA, femoral DXA, and WHO criteria (either of the sites) were 24.7%, 12.4%, and 27.8%, respectively. Sensitivity of lumbar DXA for diagnosis of osteoporosis (88.9%) was significantly higher than femoral DXA (44.6%, P<0.001); but this difference became non-significant for men > or = 60 and women > or = 70 (P=0.615 and P=0.077, respectively). Agreement of the procedures in different sites (kappa) was 0.40 (0.37 to 0.43). When proximal femur was considered as the reference, positive likelihood ratios of lumbar DXA to detect cases were 4.7 and 2.0 in younger and older groups, respectively.

CONCLUSIONS

Concerning the high rate of discordance and low agreement between DXA results, the data obtained from each anatomical site cannot predict the condition of the other site. However, if use of a single assessment is intended for screening programs, public health authorities can develop different strategies for different age groups of their population. We propose lumbar DXA for the younger group (men < 60 and women < 70) and femoral densitometry for the older.

Effect of Pre- and Post-Surgery Treatment with Risedronate on Trabecular Bone Loss in Ovariectomized Rats

The purposes of the present study were to differentiate the effects of pre-surgery treatment with risedronate and post-surgery treatment with a reduced dosing frequency of risedronate on trabecular bone loss in ovariectomized rats and to determine whether post-surgery treatment with a reduced dosing frequency of risedronate would have a beneficial effect on trabecular bone loss after pre-surgery treatment with risedronate by means of bone histomorphometric analysis. The short-term experiment (6 weeks) was performed on fifty, 4-month-old, female Sprague-Dawley rats randomized into five groups (n=10 in each group). Forty rats were treated with vehicle or risedronate for 4 weeks before ovariectomy (OVX), and then treated with either vehicle or risedronate for 2 weeks following OVX (the Vehicle-OVX-Vehicle [OVX control], Vehicle-OVX-Risedronate [post-OVX treatment with risedronate], Risedronate-OVX-Vehicle [pre-OVX treatment with risedronate], and Risedronate-OVX-Risedronate [continuous treatment with risedronate] groups). The remaining 10 rats were treated with vehicle for 6 weeks, with a sham operation performed 4 weeks after the start of the experiment (the Vehicle-Sham-Vehicle [Sham control] group). During the 4 weeks prior to surgery, risedronate was administered five times a week subcutaneously at a dose of 2.5 microg /kg body weight, and during the 2 weeks after surgery, the dosing frequency was reduced to twice a week. The long-term experiment (10 weeks) had the same design as the short-term one, except that the post-OVX treatment was 6 weeks. In the short-term experiment, both pre- and post-OVX treatments with risedronate prevented trabecular bone loss of the proximal tibial metaphysis 2 weeks after OVX. In long-term experiment, however, pre- and post-OVX treatments with risedronate attenuated trabecular bone loss until 6 weeks after OVX, with pre-OVX treatment having a less pronounced effect than post-OVX treatment. In the short- and long-term experiments, pre-and post-OVX treatments had an additive effect on trabecular bone mass. The present study has shown the efficacy of pre-OVX treatment with risedronate or post-OVX treatment with a low dosing frequency of risedronate for preventing trabecular bone loss early after OVX. Post-OVX treatment with a low dosing frequency of risedronate was beneficial for attenuating trabecular bone loss late after OVX. Treatment with risedronate before OVX had an additive effect on trabecular bone mass with the treatment after OVX, suggesting that treatment with a low dosing frequency of risedronate might be acceptable for reducing OVX-induced trabecular bone loss after treatment with risedronate prior to OVX.

Management of Low Bone Mineral Density in Premenopausal Women

OBJECTIVE

To review evidence for management of low bone density in premenopausal women and to establish practical guidelines for management of low bone density in this population by family physicians.

METHOD

A search of MEDLINE for relevant articles published between January 1990 and May 2004 was conducted. Articles retrieved were graded by level of evidence. Recommendations for diagnosis and therapy were based on evidence from randomized controlled trials and expert consensus.

RESULTS

Low bone density in premenopausal women is not associated with the same increased risk of fracture seen in older women. In the absence of fragility fractures and loss of height, it may be a reflection of low peak bone mass and may represent the normal variation in bone mineral density (BMD). Women may have low bone density secondary to an underlying skeletal or systemic disorder. Common causes of low bone density in premenopausal women include ovulatory disturbances and low body weight.

CONCLUSION

Osteoporosis is diagnosed in the premenopausal female population in the presence of fragility fractures and is not based solely on the results of BMD testing. Secondary causes of bone loss should be excluded, and any underlying condition contributing to low bone density should be corrected. Antiresorptive therapy has been evaluated only in those premenopausal women who are on glucocorticoid therapy and in those with primary hyperparathyroidism. Only in these conditions has antiresorptive therapy been shown to improve BMD.

Treatment of low bone mass in premenopausal women: when may it be appropriate?

The diagnosis and treatment of osteoporosis in postmenopausal women has been well defined. Criteria for making a diagnosis using bone density testing has been established and widely disseminated. However, the definition established by the World Health Organization for osteoporosis cannot be used for other populations such as premenopausal women without further study. Measuring bone mass in premenopausal women should be done infrequently and only if specific and significant risk factors are present. Premenopausal women have a low risk for fracturing but women with low bone mass are at a greater risk for developing fractures before and after menopause. The major reason for low bone mass is the failure to reach peak bone mass because of genetic influences, although some environ-mental factors may also play a role. Hormonal therapy for hypogonadism, treatment of diseases such as hyperpara-thyroidism, and keeping medications with detrimental effects on bone to a minimum are important components of treatment. Pharmacologic treatment of low bone mass in premenopausal women has not been well studied although on rare occasions it may be appropriate in women with low bone mass, defined as a Z score of -2 or less, and the presence of other diseases or risk factors. Caution is urged because of the unknown effects of treatment in this population. Further study of the implications of low bone mass and the effects of treatment in this group of women is needed.

Physiological aspects and clinical sequelae of energy deficiency and hypoestrogenism in exercising women

Amenorrhoea associated with reduced caloric intake and strenuous exercise leads to hypoestrogenism and is associated with clinical manifestations that include disordered eating, stress fractures, osteoporosis, and, as recently reported, a potential increase in the risk of premature cardiovascular disease. Disordered eating, menstrual irregularities and bone loss comprise the clinical condition known as the 'female athlete triad'. The aetiology of the triad is linked to a high prevalence of disordered eating and cognitive restraint. This results in inadequate caloric intake for high exercise energy expenditures that leads to energy deficiency. This in turn stimulates compensatory mechanisms, such as weight loss or energy conservation, subsequently causing a central suppression of reproductive function and concomitant hypoestrogenism. Because the aetiology of menstrual disturbances and the female athlete triad is causally linked to energy deficiency, there is no justification for fears that exercise itself is unhealthy for women. However, improved detection, monitoring, and treatment of all components of the triad in exercising women should be emphasized. This paper critically reviews the physiological aspects and clinical sequelae of energy deficiency and hypoestrogenism associated with the female athlete triad in exercising women.