Time Of Dual-energy X-ray Absorptiometry Research Articles

Femora of women with premature ovarian insufficiency exhibit reduced strength and misalignment with the transmitted vertical forces from the upper body.

Women with premature ovarian insufficiency (POI) lack oestrogen, which is a key determinant of bone growth, epiphyseal closure, and bone tissue organisation. Although dual-energy X-ray absorptiometry (DXA)-derived areal bone mineral density (BMD) remains the gold standard for fracture risk evaluation, it does not fully characterise the skeletal abnormalities present in these women. Hence, we aimed to assess hip/femur anatomy, strength, and geometry and femoral alignment using advanced hip analysis (AHA). We conducted a cross-sectional, case-control study including 89 women with spontaneous normal karyotype POI (s-POI) or iatrogenic POI (i-POI), aged 20-50 years compared with 89 age- and body mass index (BMI)-matched population-based female controls. Hip anatomy, strength, geometrical parameters, and femur alignment were measured using hip DXA images and Lunar AHA software. Femoral orientation angle (FOA) was quantified as the overall orientation of the femur with respect to the axis of the forces transmitted from the upper body. The median age of POI diagnosis was 35 (18-40) years; the mean POI duration at the time of DXA was 2.07 (range 0-13) years, and 84% of POI women received oestrogen therapy. Areal BMD at all sites was significantly lower in the POI group (all P < .05). Indices of compressive and bending strength were lower in women with POI compared with controls, specifically the cross-sectional area (CSA, mm2) and section modulus (SM, mm3) (139.30 ± 29.08 vs 157.29 ± 22.26, P < .001 and 665.21 ± 129.54 vs 575.53 ± 150.88, P < .001, respectively). The FOA was smaller (124.99 ± 3.18) in women with POI as compared with controls (128.04 ± 3.80; P < .001) at baseline and after adjusting for height and femoral neck BMD. Alongside lower BMD at multiple sites, the femora of women with POI demonstrate reduced strength and a misalignment with forces transmitted from the upper body. Further research is needed to establish the role of these newly identified features and their role in fracture risk prediction in this population.

Radiotherapy-related insufficiency fractures and bone mineral density: what is the connection?

Radiotherapy-related insufficiency fractures (RRIFs) represent a common, burdensome consequence of pelvic radiotherapy. Their underlying mechanisms remain unclear, and data on the effect of osteoporosis are contradictory, with limited studies assessing bone mineral density (BMD) by dual-energy x-ray absorptiometry (DXA). BMD by DXA (Hologic) scan and fracture risk following pelvic RRIF were retrospectively assessed in 39 patients (median age 68 years) at a tertiary cancer centre. Patient characteristics and treatment history are presented narratively; correlations were explored using univariate regression analyses. Additional cancer treatments included chemotherapy (n = 31), surgery (n = 20) and brachytherapy (n = 19). Median interval between initiation of radiotherapy and RRIF was 11 (7.5-20.8) and that between RRIF and DXA 3 was (1-6) months. Three patients had normal BMD, 16 had osteopenia and 16 osteoporosis, following World Health Organization classification. Four patients were <40 years at the time of DXA (all Z-scores > -2). Median 10-year risk for hip and major osteoporotic fracture was 3.1% (1.5-5.7) and 11.5% (7.1-13.8), respectively. Only 33.3% of patients had high fracture risk (hip fracture >4% and/or major osteoporotic >20%), and 31% fell above the intervention threshold per National Osteoporosis Guidelines Group (NOGG) guidance (2017). Higher BMD was predicted by lower pelvic radiotherapy dose (only in L3 and L4), concomitant chemotherapy and higher body mass index. At the time of RRIF, most patients did not have osteoporosis, some had normal BMD and overall had low fracture risk. Whilst low BMD is a probable risk factor, it is unlikely to be the main mechanism underlying RRIFs, and further studies are required to understand the predictive value of BMD.

Normal anthropometry does not equal normal body composition in pediatric intestinal failure.

Published reports on abnormal body composition in pediatric patients with intestinal failure have been in patients with poor growth. The goal of the current study is to reportthe bodycomposition ofnormally growing patients with intestinal failure. Children 8-18 years old with a dual-energy x-ray absorptiometry (DXA) between January 1, 2013, and July 15, 2018, were included in the study. Data were retrospectively collected from the medical charts and included demographics, residual bowel anatomy, nutrition support, height, and weight. DXA data, including total body less head bone mineral density (BMD), fat mass (FM), and fat-free mass (FFM), were collected and compared with published literature controls matched for age and sex. Thirty-four children met inclusion criteria. Mean age at the time of DXA was 9.6 ± 1.8 years. Weight- and height-for-age z-scores were -0.4 ± 0.9 and -0.5 ± 1.0, respectively. Mean BMD z-score was -1.0 ± 1.3. Twenty-six percent of patients(n = 9)had reduced BMD. Patients with intestinal failure had higher FM (P = .02) and lower FFM (P = .02) compared with controls. These data show that, despite reference range z-scores for height and weight, children with intestinal failure are at risk for abnormal body composition. Body composition should be routinely measured in children with intestinal failure to direct nutrition interventions.

Incomplete Atypical Femoral Fractures: Assessing the Diagnostic Utility of DXA by Extending Femur Length

Atypical femoral fractures (AFFs) are associated with prolonged bisphosphonate therapy. A feature of incomplete AFF is a localized periosteal reaction. It has been suggested that extending the length of the femur image at the time of dual-energy X-ray absorptiometry (DXA) may diagnose an incomplete AFF. In patients older than 50 yr on bisphosphonate therapy for more than 5 yr, we extended femur length at the time of routine DXA. Abnormal DXA images were suggested in 19 of 257 patients (7.4%). On X-ray, 7 patients (2.7%) showed no abnormality, 7 patients (2.7%) showed evidence of AFF, and 5 patients (2.0%) showed an unrelated radiographic abnormality. Of the 7 cases with X-ray evidence of AFF, 5 had a periosteal flare and 2 had a visible fracture line, both of whom needed insertion of an intramedullary nail. We demonstrated that it is feasible to detect incomplete AFF early using extended femur length imaging with a prevalence in our sample of 2.7% (95% confidence interval: 1.7%–3.7%).

Associations between adverse social position and bone mineral density in women aged 50 years or older: data from the Manitoba Bone Density Program

We examined the independent contribution of income to low bone mineral density in women aged 50 years and older. A significant dose-response association was observed between low income and low (bone mineral density) BMD, which was not explained by clinical risk factors or osteoporotic treatment in the year prior. The association between social disadvantage and osteoporosis is attracting increased attention; however, little is known of the role played by income. We examined associations between income and bone mineral density (BMD) in 51,327 women aged ≥50 years from Manitoba, Canada. Low BMD was defined as a T-score ≥2.5SD (femoral neck or minimum) measured by dual energy X-ray absorptiometry (DXA) 1996-2001. Mean household income was extracted from Canada Census 2006 public use files and categorized into quintiles. Age, weight and height were recorded at time of DXA. Parental hip fracture was self-reported. Diagnosed comorbidities, including osteoporotic fracture and rheumatoid arthritis, were ascertained from hospital records and physician billing claims. Chronic obstructive pulmonary disease was used as a proxy for smoking and alcohol abuse as a proxy for high alcohol intake. Corticosteroid use was obtained from the comprehensive provincial pharmacy system. Logistic regression was used to assess relationships between income (highest income quintile held as referent) and BMD, accounting for clinical risk factors. Compared to quintile 5, the adjusted odds ratio (OR) for low BMD at femoral neck for quintiles 1 through 4 were, respectively, OR1.41 (95%CI 1.29-1.55), OR1.32 (95%CI 1.20-1.45), OR1.19 (95%CI 1.08-1.30) and OR1.10 (95%CI 1.00-1.21). Similar associations were observed when further adjustment was made for osteoporotic drug treatment 12 months prior and when low BMD was defined by minimum T-score. Lower income was associated with lower BMD, independent of clinical risk factors. Further work should examine whether lower income increases the likelihood of treatment qualification.

Vitamin D Deficiency and Its Association With Low Bone Mineral Density, HIV-Related Factors, Hospitalization, and Death in a Predominantly Black HIV-Infected Cohort

Low bone mineral density (BMD) is common among patients infected with human immunodeficiency virus (HIV) and present in higher rates in black subjects. This study assessed vitamin D levels in HIV cases versus noninfected matched controls to determine if deficiency was associated with BMD and HIV clinical outcomes. In total, 271 military beneficiaries with HIV underwent dual energy x-ray absorptiometry (DEXA) screening in 2001-2. Serum 25OH-vitamin D levels were determined using stored serum from the time of DEXA and 6-18 months prior. Two non-HIV-infected controls for each active duty case (n = 205) were matched on age, sex, race, zip code, and season using the Department of Defense Serum Repository (DoDSR). Vitamin D levels <20 ng/mL were considered deficient. HIV-related factors and clinical outcomes were assessed using data collected in the DoD HIV Natural History study. In total, 165 of 205 (80.5%) active duty HIV cases had 2 matched controls available. HIV cases had greater odds of for vitamin D deficiency (VDD) compared with controls (demographics adjusted paired data odds ratio [OR], 1.46, 95% confidence interval [CI], .87-2.45), but this was not statistically significant. Blacks were disproportionately deficient (P <.001) but not relative to HIV status or BMD. Low BMD was associated with typical risk factors (low body mass index and exercise levels, alcohol use); given limited available data the relationship between tenofovir exposure and VDD or low BMD could not be determined. Analysis of HIV-specific factors and outcomes such as exposure to antiretrovirals, HIV progression, hospitalizations, and death revealed no significant associations with vitamin D levels. VDD was highly prevalent in black HIV- infected persons but did not explain the observed racial disparity in BMD. Vitamin D deficiency was not more common among HIV- infected persons, nor did it seem associated with HIV- related factors/clinical outcomes.

Association of osteonecrosis and osteoporosis in HIV-1-infected patients

We questioned whether heightened impairment of regenerative capacity of osteoblasts might account for the excess of osteonecrosis and osteoporosis seen in HIV-infected patients. Were that the case, patients with osteonecrosis would have more osteoporosis than the patients without osteonecrosis. Eleven thousand, five hundred and six patients with HIV infection were studied for the presence of osteonecrosis and osteoporosis and for confounding factors. Depending upon whether dual-energy X-ray absorptiometry (DEXA) was before or after the diagnosis of osteonecrosis, osteoporosis was between 6.3 and 18 times more frequent in those with than in those without osteonecrosis. Those who received DEXA were similar to those who did not in median CD4 level at the time of DEXA or at a comparable time after their first recorded CD4 cell count in our system; in nadir CD4 level; and in use and amount of corticosteroids. Those with osteonecrosis and osteoporosis did not use more corticosteroids than those with osteoporosis without osteonecrosis. Alcohol abuse had not been diagnosed more often before the occurrence of osteonecrosis than in those without osteonecrosis. Tenofovir was not more used by those with than by those without osteoporosis. Osteonecrosis and osteoporosis in HIV-infected patients were concurrent more often than expected.

Corticosteroid Exposure Not Associated With Long‐term Bone Mineral Density in Pediatric Liver Transplantation

The aim of the study was to examine the association of corticosteroid exposure and other skeletal risk factors with bone mineral density (BMD) and fractures following pediatric liver transplantation (LT) at a large single center. Lumbar spine BMD, measured using dual-energy x-ray absorptiometry (DXA), was corrected for bone age in 52 ambulatory children ages 4 to 18 years, at least 1 year post-LT. Potential risk factors for skeletal health such as corticosteroid exposure, dietary and lifestyle factors, and growth and fracture occurrence, were related to BMD using univariate and multivariate regression analyses. The prevalence of low BMD (z score <-2) and post-LT fractures was 3 of 52 (5.8%) and 11 of 52 (21%), respectively. Univariate analysis revealed age >10 years at LT and body mass index (BMI) < 85th percentile at time of DXA were significantly associated with BMD (both P = 0.02). BMD did not correlate with corticosteroid dosage in the first year post-LT, the year before DXA or cumulative lifetime exposure. A cholestatic primary LT indication, acute rejection episodes, and fractures post-LT were not associated with BMD. Extracurricular physical activity, vitamin D, and calcium intake were not associated with BMD or fractures. Multivariate linear regression revealed increased time post-LT (P = 0.04) and higher BMI z score at time of DXA (P = 0.02) as the strongest independent variables associated with greater BMD. Neither corticosteroid exposure nor a cholestatic primary indication for LT influenced BMD, which was largely normal in this ambulatory group. Children and adolescents undergoing LT after the age of 10 years and those with low BMI post-LT may be at greatest risk of poor skeletal health later in life, and thus a potential target patient population to benefit from preventive interventions.

Vitamin D insufficiency in a large female SLE cohort

The objective of this study was to determine the vitamin D status and its relationship with disease and therapy features and with bone mineral density in women with systemic lupus erythematosus. Non-pregnant systemic lupus erythematosus women with dual-energy X-ray absorptiometry and vitamin D measurements performed between May 1 2005 and August 31 2006 were studied. In each patient, the lowest T-score of the first dual-energy X-ray absorptiometry scan during the study period was used. In postmenopausal women, a T-score > or = 1.0 standard deviation was considered normal, between -1.0 and -2.5 standard deviations osteopenia and < or = 2.5 standard deviations osteoporosis; in premenopausal women a T-score > or = 2.5 standard deviations was normal and < or = 2.5 standard deviations defined as reduced bone density. 25-hydroxyvitamin D and 1,25-dihydroxyvitamin D levels were determined at the time of dual-energy X-ray absorptiometry. A 25-hydroxyvitamin D level of <80 nmol/L was defined as sub-optimal and a level <40 nmol/L as deficient. Demographic and clinical variables were investigated for association with vitamin D levels by univariate and multivariate analyses. One-hundred and twenty-four systemic lupus erythematosus women had dual-energy X-ray absorptiometry scans and vitamin D assays performed during the study period. Sub-optimal 25-hydroxyvitamin D levels were found in 82 (66.7%) and deficient 25-hydroxyvitamin D levels in 22 (17.9%) patients. The disease-related features examined at the time of vitamin D assays or bone mineral density showed no correlation with vitamin D levels by univariate analyses. Neither 25-hydroxyvitamin D nor 1,25-dihydroxyvitamin D was associated with bone mineral density status among these patients. A multivariate logistic regression model identified season, cumulative glucocorticoid exposure, and serum creatinine as being associated with 25-hydroxyvitamin D levels, whereas ethnicity, glucocorticoid exposure, and serum creatinine were associated with 1,25-dihydroxyvitamin D levels. In conclusion, sub-optimal vitamin D status is common in women with systemic lupus erythematosus and is related to season, cumulative glucocorticoid dose, and serum creatinine.

Impact of HIV Infection on Total Body Composition in Treatment—Naive Men Evaluated by Dual-Energy X-ray Absorptiometry Comparison of 90 Untreated HIV-Infected Men to 241 Controls

The aim of this study was to establish the contribution of human immunodeficiency virus (HIV) itself on body composition changes evaluated by dual-energy X-ray absorptiometry (DXA). Body composition evaluated by DXA in 90 HIV never treated men, without comorbidity, or current or past opportunistic infections were compared with 241 healthy volunteers. The mean duration of seropositivity from HIV diagnosis was 41 ± 62 mo, mean CD4 and viral load at the time of DXA were 402/mm 3 ± 263 (control values 500–1200/mm 3) and 4.2 log copies/mL ± 1.3. Mean age (41 vs 39 yr, respectively, for HIV never treated patients and controls) and mean height (174.5 vs 176 cm) were not different, but mean weight was lower among HIV never treated patients (69.8 vs 78.7 kg). Mean total body bone mineral density (BMD) of naive HIV-infected patients was lower than that of controls (1.20 vs 1.23 g/cm 2, p = 0.01) but not after adjustment on age, height, lean mass (LM), and fat mass ratio (FMR = % trunk fat mass/% lower limb fat mass). Fat mass (13.2 vs 16.5 kg, p < 0.0001) and LM (53.5 vs 59 kg, p < 0.0001) of naive HIV-infected patients were lower whatever the adjustment variables. The FMR was lower in naive HIV-infected men (1.0 vs 1.3, p < 0.0001) because of a decreased trunk fat mass. After adjustment on age, height, LM, and fat mass, the lower limbs fat mass percentage was higher in HIV-infected men. The profile of naïve HIV-infected patients displayed low lean and fat masses, and a fat mass repartition characterized by a predominant loss in the trunk. Those alterations may result from the catabolic effect of the chronic HIV infection.

Osteoporosis in systemic lupus erythematosus: factors associated with referral for bone mineral density studies, prevalence of osteoporosis and factors associated with reduced bone density

The purpose of this study was to evaluate the clinical characteristics of women with systemic lupus erythematosus (SLE) sent for a dual energy X-ray absorptiometry (DEXA) study, and to analyse the factors associated with a lower bone mineral density in these patients. Women with SLE who had a DEXA done between 1 January 1995 and 31 December 2000 were compared with those who did not have DEXA scans performed. SLE patients with osteoporosis (OP) were compared with those with a normal bone density. Of 516 women with SLE, 205 had a DEXA done. These patients had more traditional risk factors for osteoporosis, higher lupus disease activity, renal involvement, increased damage, higher mean steroid dose, increased use of immunosuppressants and occurrence of avascular necrosis. Of the 205 patients with DEXA, 18% had osteoporosis, 48.8% had osteopenia and 33.2% had normal bone mineral density. The two statistically significant predictors of a low bone density were a higher age at time of DEXA (P = 0.0003) and a higher SDI score (P = 0.0019). Osteoporosis is a significant comorbidity in SLE. Lupus patients referred for a DEXA have more traditional risk factors and use more corticosteroids. The main factors associated with a low bone density were however found to be age and increased damage. Interestingly, disease activity and corticosteroid use were not associated with osteoporosis in this study which may suggest other potential causes such as decreased physical activity associated with damage.

Bone mineral density after surgical treatment for Graves' disease.

Restoration of bone loss associated with thyrotoxicosis follows normalization of thyroid function. However, the extent of bone loss and restoration remain controversial. To clarify whether bone recovery is complete, we examined lumbar and femoral bone mineral density (BMD) by dual-energy x-ray absorptiometry (DXA) in 14 thyrotoxic premenopausal women with Graves' disease and 31 premenopausal women treated for Graves' disease by subtotal thyroidectomy who had been in remission for at least 3 years. In the remission group, to exclude the influence of subclinical hyperthyroidism, thyrotropin (TSH) levels were followed and subjects with low levels excluded. Thus, all 31 subjects had normal thyroid hormone levels with transiently or persistently elevated TSH levels post-thyroidectomy. Data from the two study groups were compared with those from healthy premenopausal controls matched for age, height and weight. Mean lumbar (anterior-posterior and lateral), femoral neck, and trochanter BMDs were significantly lower in the thyrotoxic group than in controls (p < .05, all four BMDs). Mean lumbar (anterior-posterior), femoral neck and trochanter BMDs were significantly higher in the remission group than in controls (p < 0.05, all three BMDs). At the time of DXA, the 31 remission subjects showed a significant positive correlation between lumbar BMD and TSH (p < 0.05) and a significant negative correlation between femoral neck BMD and free triiodothyronine (FT3) (p < 0.05). These observations suggest: (1) in premenopausal women, bone loss associated with thyrotoxicosis due to Graves' disease is present but is fully restored when remission is reached after subtotal thyroidectomy; (2) subclinical hypothyroidism after subtotal thyroidectomy may result in higher BMD than that of controls.