Dual-energy X-ray absorptiometry (DXA) is recognized as the reference method to measure bone mineral density (BMD) with acceptable accuracy errors and good precision and reproducibility. The World Health Organization (WHO) has established DXA as the best densitometric technique for assessing BMD in postmenopausal women and based the definitions of osteopenia and osteoporosis on its results. DXA allows accurate diagnosis of osteoporosis, estimation of fracture risk and monitoring of patients undergoing treatment. However, when DXA studies are performed incorrectly, it can lead to major mistakes in diagnosis and therapy. This article reviews the fundamentals of positioning, scan analysis and interpretation of DXA in clinical practice.

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Bone is commonly affected in cancer. Cancer-induced bone disease results from the primary disease, or from therapies against the primary condition, causing bone fragility. Bone-modifying agents, such as bisphosphonates and denosumab, are efficacious in preventing and delaying cancer-related bone disease. With evidence-based care pathways, guidelines assist physicians in clinical decision-making. Of the 57 million deaths in 2008 worldwide, almost two thirds were due to non-communicable diseases, led by cardiovascular diseases and cancers. Bone is a commonly affected organ in cancer, and although the incidence of metastatic bone disease is not well defined, it is estimated that around half of patients who die from cancer in the USA each year have bone involvement. Furthermore, cancer-induced bone disease can result from the primary disease itself, either due to circulating bone resorbing substances or metastatic bone disease, such as commonly occurs with breast, lung and prostate cancer, or from therapies administered to treat the primary condition thus causing bone loss and fractures. Treatment-induced osteoporosis may occur in the setting of glucocorticoid therapy or oestrogen deprivation therapy, chemotherapy-induced ovarian failure and androgen deprivation therapy. Tumour skeletal-related events include pathologic fractures, spinal cord compression, surgery and radiotherapy to bone and may or may not include hypercalcaemia of malignancy while skeletal complication refers to pain and other symptoms. Some evidence demonstrates the efficacy of various interventions including bone-modifying agents, such as bisphosphonates and denosumab, in preventing or delaying cancer-related bone disease. The latter includes treatment of patients with metastatic skeletal lesions in general, adjuvant treatment of breast and prostate cancer in particular, and the prevention of cancerassociated bone disease. This has led to the development of guidelines by several societies and working groups to assist physicians in clinical decision making, providing them with evidencebased care pathways to prevent skeletal-related events and bone loss. The goal of this paper is to put forth an IOF position paper addressing bone diseases and cancer and summarizing the position papers of other organizations. Epidemiology of cancer-associated bone disease Bone metastasisCancer affects nearly 12.7 million people and is associated with over 7 million deaths in 2008 [1]. Cancer is a rising global health burden and it is estimated that in 2030, cancer deaths will be tallied at over 13 million (World Health Organization (WHO) 2010 Global Status Report [2]). Addressing the morbidity and mortality of cancer is an important public health concern. On purpose, we are limiting our analysis to cancer bone involvement in adults and do not discuss cancer in children.Metastases from cancer are associated with 90 % of cancer deaths [3]. It was estimated that one half of people who die from cancer in the USA have bone involvement [4][5][6]. Different tumou...

Few reports are available on bone turnover in type 2 diabetes. Impaired bone turnover in type 2 diabetes appears to result from decreased bone formation. Studies also suggest that poor glycaemic control in type 2 diabetes may contribute to osteopaenia. The aim of this study was to investigate biochemical markers of bone turnover in males with poorly controlled type 2 diabetes and look for correlations with glycaemic control and gonadal and hypophyseal hormonal axis. Consecutive male patients with poorly controlled type 2 diabetes and attending the internal medicine department during a period of 6 months were enrolled. The patients were receiving oral hypoglycaemic agents (metformin or sulphonylureas or both). None of the patients had any evidence of macroangiopathy, nephropathy or neuropathy. Only two patients had proliferative retinopathy. Serum osteocalcin, crosslaps (C-telopeptide, CTx), parathyroid hormone (PTH), testosterone, oestrogen, prolactin, follicle-stimulating hormone (FSH) and luteinising hormone (LH) were measured in 35 patients and 35 controls. The mean age of the study population was 53.7 (10.3) years (range: 50.2-57.3) and the mean disease duration was 8.6 (6.0) years (range: 6.5-10.7). No differences between patients and controls were observed in serum calcium, phosphorus, creatinine, albumin, PTH, CTx, oestrogen, testosterone, LH, FSH, prolactin and urinary calcium. Patients had lower serum levels of osteocalcin than controls with a significant statistical difference [15.3 (4.1) vs 18.3 (5.3), p=0.012]. There was a negative significant statistical correlation between CTx levels and HbA1c (r=-0.41, p< 0.05). Our study suggested that bone formation is altered in type 2 diabetes and that bone turnover is affected by glycaemic control status.

The objectives of the study were to determine the 2 year rate of bone changes in patients with ankylosing spondylitis (AS) and, whether bone loss is related to physical impairment, systemic inflammation. and therapy. Consecutive outpatients fulfilling the modified New York criteria for AS were included. Baseline assessment included age, disease duration, treatment, clinical, radiologic and laboratory data. Erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP) were determined every 6 months. Persistent systemic inflammation was defined as mean ESR > or = 28 mm/h or mean CRP > or = 15 mg/l. Bone mineral density (BMD) at the lumbar spine and femoral neck was measured by dual-energy X-ray absorptiometry, at baseline and year 2. Statistical analysis compared the baseline and 24 month follow-up BMD data, and determined whether baseline data, and persistent systemic inflammation during the 2 years, were related to the 24 month percentage changes in BMD. Fifty-four patients (35 men, 19 women; mean age 37.3 +/- 11.3 years, mean disease duration 12.4 +/- 8.6 years) were included. After 2 years, BMD did not change at the lumbar spine (+0.75% +/- 3.5, p = 0.23), and decreased at the femoral neck (-1.6% +/- 4, p = 0.006). The 24 month percentage change in femoral neck BMD was related to persistent systemic inflammation, defined using ESR (mean percentage change -4.1% +/- 5.7 and -1.2% +/- 3.9 in patients with and without persistent inflammation; respectively; p = 0.007). These results suggest that persistent inflammation might be an etiologic factor of bone loss in AS.

RA is a risk factor on its own for the development of osteoporosis and VFs and this risk increases more with low weight, disease duration and severe course of disease. These findings may suggest that to prevent the development of VFs, precautions should be taken immediately to suppress the disease activity and correct the weight loss in patients with RA.

BackgroundOsteoporosis is a well-known complication of ankylosing spondylitis (AS). However, data about body composition modifications and muscle performance showed conflicting results. The aim of the study was to determine the prevalence and risk factors of pre-sarcopenia, sarcopenia and cachexia in patients with AS and analyze its relationship with bone loss and symptomatic and severity parameters of the disease.MethodsSixty-seven consecutive male patients with AS (mean age of 40.9 ± 11.0 years) and 67 healthy controls were studied. Body composition and bone mineral density (BMD) scans were obtained using DXA. The fat-free mass index (FFMI; fat-free mass divided by height squared) and the percent of fat mass (%FM) were calculated. Pre-sarcopenia was defined by low skeletal muscle mass (SMI <7.25 kg/m2), sarcopenia by the combined presence of the two following criteria: SMI <7.25 kg/m2 and a low muscle strength (handgrip strength <30 kg) or a low muscle performance (timed get-up-and-go test >10 s) and cachexia by a BMI <20 kg/m2 plus 3 from the 5 following parameters: anorexia, fatigue, handgrip strength <30 kg, CRP >5 mg/l, SMI <7.25 kg/m2.ResultsPre-sarcopenia, sarcopenia, cachexia, and osteoporosis prevalences were (50.4, 34.3, 11.9, and 16.0) respectively. Patients had a mean 3 kg significant decrease in FFM and a 1 kg/m2 decrease in appendicular mass vs. healthy controls. Pre-sarcopenia, sarcopenia and cachexia were significantly associated to higher BASDAI levels and low BMD.ConclusionOur study showed that men with AS had a statistically significant reduction in total and appendicular lean mass that is related to higher disease activity and significantly associated to bone loss.Electronic supplementary materialThe online version of this article (doi:10.1186/s12891-016-1155-z) contains supplementary material, which is available to authorized users.