DXA scanning

The association of gender-affirming hormone therapy duration and body mass index on bone mineral density in gender diverse adults

Introduction

Feminizing and masculinizing gender-affirming hormone therapy (fGAHT, mGAHT) results in bone mineral density (BMD) maintenance or improvement over time in transgender and gender diverse (TGD) adults. Mostly European TGD studies have explored GAHT's impact on BMD, but the association of BMI and BMD in TGD adults deserves further study.

Objective

To determine whether GAHT duration or BMI are associated with BMD and Z-scores among TGD young adults.

Methods

Cross-sectional study of nonsmoking TGD adults aged 18-40 years without prior gonadectomy or gonadotropin-releasing hormone agonist (GnRHa) therapy taking GAHT for > 1 year. BMD and Z-scores were collected from dual-energy x-ray absorptiometry. Associations between femoral neck, total hip, and lumbar spine BMDs and Z-scores and the predictors, GAHT duration and BMI, were estimated using linear regression.

Results

Among 15 fGAHT and 15 mGAHT, mean BMIs were 27.6 +/- standard deviation (SD) 6.4 kg/m2 and 25.3 +/- 5.9 kg/m2, respectively. Both groups had mean BMDs and Z-scores within expected male and female reference ranges at all three sites. Higher BMI among mGAHT was associated with higher femoral neck and total hip BMDs (femoral neck: β = 0.019 +/- standard error [SE] 0.007 g/cm2, total hip: β = 0.017 +/- 0.006 g/cm2; both p < 0.05) and Z-scores using male and female references. GAHT duration was not associated with BMDs or Z-scores for either group.

Conclusions

Z-scores in young, nonsmoking TGD adults taking GAHT for > 1 year, without prior gonadectomy or GnRHa, and with mean BMIs in the overweight range, were reassuringly within the expected ranges for age based on male and female references. Higher BMI, but not longer GAHT duration, was associated with higher femoral neck and total hip BMDs and Z-scores among mGAHT. Larger, prospective studies are needed to understand how body composition changes, normal or low BMIs, and gonadectomy affect bone density in TGD adults.

Bone Mineral Density and Current Bone Health Screening Practices in Friedreich's Ataxia

Introduction

Friedreich's Ataxia (FRDA) is a progressive neurological disorder caused by mutations in both alleles of the frataxin (FXN) gene. Impaired bone health is a complication of other disorders affecting mobility, but there is little information regarding bone health in FRDA.

Methods

Dual energy X-ray absorptiometry (DXA) scan-based assessments of areal bone mineral density (aBMD) in individuals with FRDA were abstracted from four studies at the Children's Hospital of Philadelphia (CHOP). Disease outcomes, including the modified FRDA Rating Scale (mFARS), were abstracted from the FRDA Clinical Outcomes Measures Study (FACOMS), a longitudinal natural history study. A survey regarding bone health and fractures was sent to individuals in FACOMS-CHOP.

Results

Adults with FRDA (n = 24) have lower mean whole body (WB) (-0.45 vs. 0.33, p = 0.008) and femoral neck (FN) (-0.71 vs. 0.004, p = 0.02) aBMD Z-scores than healthy controls (n = 24). Children with FRDA (n = 10) have a lower WB-less-head (-2.2 vs. 0.19, p < 0.0001) and FN (-1.1 vs. 0.04, p = 0.01) aBMD than a reference population (n = 30). In adults, lower FN aBMD correlated with functional disease severity, as reflected by mFARS (R = -0.56, p = 0.04). Of 137 survey respondents (median age 27 y, 50% female), 70 (51%) reported using wheelchairs as their primary ambulatory device: of these, 20 (29%) reported a history of potentially pathologic fracture and 11 (16%) had undergone DXA scans.

Conclusions

Low aBMD is prevalent in FRDA, but few of even the highest risk individuals are undergoing screening. Our findings highlight potential missed opportunities for the screening and treatment of low aBMD in FRDA.

Ankylosing spondylitis and bone mineral density--what is the ideal tool for measurement?

Ankylosing spondylitis (AS) is characterised by chronic inflammation and partial ossification, yet vertebral fractures due to osteoporosis, although common, are frequently unrecognised. The aim of this study was to (1) show the frequency of changes in the progress of osteopenia/osteoporosis in AS depending on duration and stage of the disease and (2) assess the ranking of two different methods of bone density measurement in this clinical pattern. We measured bone density in 84 male and female patients with both dual X-ray absorptiometry (DXA) and single energy quantitative computed tomography (SE-QCT). In the initial and advanced stages of the disease, a high decrease in axial bone density could be verified (DXA: osteopenia in 5% and osteoporosis in 9.2%; SE-QCT: osteopenia in 11.8% and osteoporosis in 30.3%). Peripheral bone density decrease as in osteopenia could be proven in 17.6% by DXA measurement. With SE-QCT, a decrease in vertebral trabecular bone density could already be observed in the initial stage and continued steadily during the course of the disease; cortical bone displayed the same trend up to stages of ankylosis. With DXA, valid conclusions are more likely to be expected in less marked ankylosing stages of AS. In stages of advanced ankyloses in the vertebral region (substantial syndesmophytes), priority should be given to SE-QCT, due to the selective measurement of trabecular and cortical bone. The DXA method often yields values that are too high, and the replacement of vertebral trabecular bone by fatty bone marrow is not usually recorded as standard. There may already be an increased risk of bone fracture in AS in osteopenia on DXA along with an osteoporosis already established on SE-QCT.

Alterations of bone mineral density and bone metabolism in patients with various grades of chronic pancreatitis

The aim of this study was to examine bone mineral density (BMD) and bone metabolism in patients with chronic pancreatitis to determine if increased severity of the disease would correlate with increased bone loss. Between October 1999 and September 2000, we investigated 42 patients with an average age of approximately 53 years suffering from chronic pancreatitis, as well as 20 healthy male controls with an average age of 49 years. Dual energy x-ray absorptiometry (DEXA) was performed on patients and controls, and serum levels of parathyroid hormone (PTH), osteocalcin (OC), carboxy-terminal propeptide of type I procollagen (CICP), bone-specific alkaline phosphatase (BAP), 1,25(OH)(2) vitamin D(3) and 25(OH) vitamin D(3), as well as fecal elastase 1 were also determined. The severity of chronic pancreatitis in patients was determined via endoscopic retrograde cholangiopancreatography (ERCP) and assigned to 1 of 3 grades based on the Cambridge classification. BMD of patients with chronic pancreatitis was markedly decreased compared to controls (means in patients: DEXA lumbar vertebra anterior/posterior (LV ap) 96.8% +/- 4.2%, DEXA Ward's triangle (WARD) 92.2% +/- 5.2%; controls: DEXA LV ap 98.7% +/- 3.7%, DEXA WARD 97.1% +/- 3.1%; P <.05 and P <.0001) and correlated with the various Cambridge-grades (DEXA LV ap and DEXA WARD, P <.01). Fecal elastase 1 showed sensitivities of 14%, 87%, and 95% for the Cambridge-grades I, II, and III, respectively, and correlated with this classification of severity of chronic pancreatitis (P <.01). Furthermore, fecal elastase 1 of patients correlated the same way with both D(3)-vitamins (P <.01), as well as with parameters of BMD (P <.01). If fecal elastase 1 in patients was below 200 micro g/g, then the BMD and vitamin D(3) values were also significantly decreased compared to those with fecal elastase 1 above 200 micro g/g. In patients with Cambridge grades II and III 1,25(OH)(2)D(3) was markedly decreased (26.7 +/- 7.7 pg/mL and 27.6 +/- 9.0 pg/mL) compared to those with Cambridge grade I (38.0 +/- 10.5 pg/mL; between I and II, P =.027; between I and III, P =.033). 25(OH)D(3) was not significantly different within the various Cambridge groups (P =.07). Compared to controls, both D(3) vitamins, as well as fecal elastase 1, were extremely low (means in patients: fecal elastase 1, 140.7 +/- 75.7 micro g/g; 1,25(OH)(2)D(3), 29.9 +/- 9.5 pg/mL; 25(OH)D(3), 26.7 +/- 9.7 nmol/L; controls: fecal elastase 1, 694.9 +/- 138.6 micro g/g; 1,25(OH)(2)D(3), 67.5 +/- 4.3 pg/mL; 25(OH)D(3), 69.5 +/- 13.5 nmol/L). A significant correlation was observed between increased severity of chronic pancreatitis based on both endoscopic retrograde cholangiopancreatography and levels of fecal elastase 1, with decreased circulating levels of vitmain D(3) and decreased BMD. This supports a connection between the inflammatory destruction of the pancreas (Cambridge classification), exocrine pancreatic insufficiency (fecal elastase 1), altered levels of vitamin D metabolites, and loss of skeletal mass.