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Biomedical subjects

Asma Arabi

Publications and source records attributed to Asma Arabi.

11 recordsLinked to original sources
PubMed2007

Discriminative ability of dual-energy X-ray absorptiometry site selection in identifying patients with osteoporotic fractures.

Dual-energy X-ray absorptiometry (DXA) is the gold standard method for measurement of bone mineral density (BMD). The aims of the current study are to compare the ability of BMD measurements to identify subjects with vertebral fractures (VF), when the lumbar spine (LS), hip or both sites are measured. 460 subjects aged 73+/-5.2 years participated in the study. Thoraco-lumbar spine radiographs were obtained and analyzed for the presence of VF using the visual semi-quantitative assessment. BMD of the LS and the left femur were measured by DXA. Eighteen men (12%) and 56 women (20%) had at least one VF. 16% of scans at the LS were unreadable because of the presence of degenerative changes. In both genders, BMD of the hip showed better ability than LS BMD in detecting subjects with osteoporosis. BMD and T-score values at the hip, but not the LS, were lower in subjects with VF than those without (p<0.05). Femoral neck BMD showed the highest OR for each S.D. decrease in BMD for identifying subjects with VF, and the best predictability for prevalent VF using ROC. Fracture risk prediction did not increase by adding the spine to the hip measurement. In conclusion, hip BMD was the only and best skeletal site needed to detect subjects with osteoporosis and showed the strongest relationship with prevalent vertebral fractures in elderly subjects.

Absorptiometry, Photon↗
PubMed2006

Regression of skeletal manifestations of hyperparathyroidism with oral vitamin D.

CONTEXT: Parathyroidectomy is the only effective therapy for osteitis fibrosa cystica in hyperparathyroidism. OBJECTIVE: The objective of this study was to describe the changes of skeletal and nonskeletal manifestations in a patient with hyperparathyroidism and renal failure after oral vitamin D therapy. DESIGN: This was a descriptive case report. SETTING: The patient was followed up in a referral center. PATIENT: A 55-yr-old male patient with moderate renal failure was referred for expansile lytic lesions affecting several ribs and the spinous process of T12. His creatinine was 1.8 mg/dl; calcium, 8.9 mg/dl; PTH, 666 pg/ml; and 1,25 dihydroxy-vitamin D, 27 pg/ml. Bone mineral density (BMD) Z-scores by dual-energy x-ray absorptiometry were -4.1 at the spine, -1.7 at the hip, and -4.3 at the forearm. MAIN OUTCOME MEASURES: The main outcome measures were the skeletal manifestations of hyperparathyroidism. RESULTS: At 10 months of therapy, calcium level was 10 mg/d, PTH level declined to 71 pg/ml, and BMD increased by 12% at the spine and 18% at the hip. Computerized tomography (CT) cuts revealed marked regression in the lytic lesions. At 2 yr, BMD increased by an additional 6% at the spine, and there were no further changes in the lytic lesions by CT. The vitamin D receptor genotype using the restriction enzymes Bsm1, Taq1, and Apa1 was Bb, tt, and AA. CONCLUSIONS: We showed regression of severe skeletal abnormalities of hyperparathyroidism documented by serial CT images in response to oral vitamin D therapy. It is possible that the vitamin D receptor genotype of the patient modulated this response.

Bone Density↗
PubMed2006

Hypovitaminosis D osteopathy: is it mediated through PTH, lean mass, or is it a direct effect?

Hypovitaminosis D is increasing worldwide and is associated with low bone mass. The effects of hypovitaminosis D on bone might be direct or mediated through decreased muscle mass and function and/or secondary hyperparathyroidism. This study systematically investigated the relative contribution of lean mass, PTH, and the direct effect of vitamin D as predictors of vitamin D mediated osteopathy in elderly individuals. 460 ambulatory subjects aged 65-85 years had their bone mass and lean body mass measured by a dual-energy X-ray absorptiometry. Serum calcium, phosphorus and alkaline phosphatase, intact parathyroid hormone (PTH) and 25-hydroxyvitamin D (25 OHD) were also measured. Serum 25 OHD correlated with lean body mass in men, r = 0.24, P = 0.002, but not in women; and with bone mass at all skeletal sites in men, r = 0.20-0.30, P < 0.02. Correlations were also noted at all skeletal sites in women except for the spine, r = 0.13-0.18, P < 0.04. In both genders, BMD at sites enriched in cortical bone was 0.4-0.7 SD lower in the group with the lowest vitamin D tertile than that in the group in the highest tertile. After controlling for PTH, the magnitude of the correlations between BMD and 25 OHD remained significant in both genders. After controlling for lean body mass, the magnitude of these correlations did not change in women and decreased but remained significant in men. After adjustment for age and height, both lean body mass and PTH had significant independent contributions to BMD variance at all skeletal sites. After adjustment for age, height, lean mass, and PTH, 25 OHD did not have any significant residual contribution to BMD variance except at the trochanter in men. This study demonstrates that vitamin D osteopathy in the elderly is in large part mediated through lean mass in men and through PTH levels in both genders, with a greater contribution of PTH in women than in men. There was little demonstrable independent relation between serum 25 OHD and bone mass.

Absorptiometry, Photon↗
PubMed2005

Effect of vitamin D replacement on musculoskeletal parameters in school children: a randomized controlled trial.

BACKGROUND: Despite the high prevalence of hypovitaminosis D in children and adolescents worldwide, the impact of vitamin D deficiency on skeletal health is unclear. METHODS: One hundred seventy-nine girls, ages 10-17 yr, were randomly assigned to receive weekly oral vitamin D doses of 1,400 IU (equivalent to 200 IU/d) or 14,000 IU (equivalent to 2,000 IU/d) in a double-blind, placebo-controlled, 1-yr protocol. Areal bone mineral density (BMD) and bone mineral content (BMC) at the lumbar spine, hip, forearm, total body, and body composition were measured at baseline and 1 yr. Serum calcium, phosphorus, alkaline phosphatase, and vitamin D metabolites were measured during the study. RESULTS: In the overall group of girls, lean mass increased significantly in both treatment groups (P < or = 0.05); bone area and total hip BMC increased in the high-dose group (P < 0.02). In premenarcheal girls, lean mass increased significantly in both treatment groups, and there were consistent trends for increments in BMD and/or BMC at several skeletal sites, reaching significance at lumbar spine BMD in the low-dose group and at the trochanter BMC in both treatment groups. There was no significant change in lean mass, BMD, or BMC in postmenarcheal girls. CONCLUSIONS: Vitamin D replacement had a positive impact on musculoskeletal parameters in girls, especially during the premenarcheal period.

Adolescent↗
PubMed2005

Impact of anthropometric, lifestyle, and body composition variables on ultrasound measurements in school children.

Quantitative ultrasound (QUS) measurement at hand phalanges was demonstrated to be a reliable method to assess skeletal maturation during childhood and adolescence. The aim of the study was to evaluate the influence of age, gender, puberty, lifestyle factors, and body composition on QUS parameters and to provide a normative database for QUS in school children in Lebanon. Measurements of phalangeal osteosonography were examined in 256 healthy subjects (132 boys and 124 girls) aged 11-18 years using an ultrasound device. In both genders, amplitude-dependent speed of sound (AD-SoS) and bone transmission time (BTT) increased significantly with age and pubertal stages. Girls had higher AD-SoS values than boys between 11 and 15 years of age and at Tanner stages III and IV; however, no differences were detected in the older age groups. AD-SoS and BTT showed a significant positive correlation with age and height in both genders (R = 0.41-0.66, P < 0.01). There was no correlation between physical activity, calcium intake, sun exposure, and any of the QUS parameters in either gender. Weight showed moderate positive correlation with AD-SoS in boys and with BTT in both genders (R = 0.31-0.47, P < 0.01). Lean mass showed significant positive correlation with AD-SoS and BTT (R = 0.2-0.68, P < 0.01) in both genders. Percentage body fat showed significant negative correlation with BTT and AD-SoS in boys (R = -0.25 to -0.37, P < 0.01). In the linear regression analyses, there was a significant negative correlation between percentage fat mass and both AD-SoS and BTT in both genders. In conclusion, QUS parameters of the phalanges in Lebanese children are related to growth variables such as height, age, and puberty in healthy children. The impact and magnitude of body composition variables and lifestyle factors on ultrasonometry derived variables differ from their effect on dual energy X-ray absorptiometry derived parameters.

Adolescent↗
PubMed2005

Densitometer type and impact on risk assessment for osteoporosis.

Studies have shown a high correlation between measurements of bone mineral density (BMD) obtained on differentdual-energy X-ray absorptiometry machines. Challenger osteodensitometers (Diagnostic Medical System [DMS],Montpellier, France) are becoming widely used but little is known about their clinical performance. The aim of this study was to compare BMD measurements and the resulting patient classification based on T-scores obtained on a DMS Challenger device to those obtained on Hologic 4500A (Bedford, MA) device. Fifty-three volunteers were studied. The BMD of the spine and of the hip were simultaneously measured on both densitometers. BMD values obtained on the Challenger were significantly higher than those obtained with the Hologic QDR4500 (p<0.001). The correlations coefficients between the Hologic QDR4500 and the DMS Challenger measured BMDs were r=0.70 at the femoral neck, r=0.70 at the trochanter, and r=0.83 at the spine (p<0.001). Among the 35 postmenopausal women, there was discordance in the WHO T-score-based classification in 28 subjects (80%) at the spine, 18 subjects (52%) at the femoral neck, and 14 subjects (42%) at the trochanter. The intermachine agreement was low: The kappa score was -0.10 at the spine, 0.2 at the femoral neck, and 0.3 at the trochanter. In conclusion, this study cautions against the use of non established densitometers that leads to underdiagnosis of patients and, subsequently, to inappropriate treatment strategies.

Absorptiometry, Photon↗
PubMed2004

Benefits of pamidronate in children with osteogenesis imperfecta: an open prospective study.

OBJECTIVES: To study the efficacy of pamidronate in children with osteogenesis imperfecta (OI). PATIENTS AND METHODS: Twenty-nine patients (median age 8.7 years), were given pamidronate in cyclic infusions of 3 days. Patients received 3-13 cycles (median 6), at a dose of 0.5 mg/kg/day in infants (below 2 years of age) and 1 mg/kg/day in children (2 years and older). The interval time between cycles was 2 months in infants and 4 months in children. The median follow-up was 16 months. All patients received daily supplementation of calcium, vitamin D and physical rehabilitation. Assessments were performed at baseline and before each cycle. Fracture rate under treatment was compared to the one in the pre-treatment period. RESULTS: Pain decreased after the first infusion cycle (P < 0.0001). The median of fracture incidence decreased from 15 to 0.5 per year in infants and from 2.0 to 1 per year in children (P = 0.04). Alkaline phosphatase decreased by 31.2% and N-telopeptide collagen cross-links decreased by 61.8% (P < 0.001). Bone mineral density (BMD) of the spine increased by a median of 55.4% (P < 0.001). Z-scores increased from a median of -4.7 to -2.6 (P < 0.001). The femoral neck, BMD increased by a median of 16%. The area of the first four lumbar vertebrae increased by a median of 21.5% (P < 0.001). No adverse effect on growth or on fracture healing was observed. Side effects were symptomatic hypocalcemia in one infant, and the transient acute phase reaction. CONCLUSION: Pamidronate increases BMD, decreases bone remodeling markers, pain and fracture rate in infants and children with OI.

Adolescent↗
PubMed2004

Bone mineral density by age, gender, pubertal stages, and socioeconomic status in healthy Lebanese children and adolescents.

Gender, ethnicity, and lifestyle factors affect bone mass acquisition during childhood, thus the need for age- and sex-adjusted Z scores using ethnic-specific data for bone mineral density (BMD) measurement. This study aimed at establishing normative data for BMD in healthy Lebanese children and adolescents. Three hundred sixty-three healthy children aged 10 to 17 years (mean+/-SD: 13.1+/-2.0) were studied. BMD, bone mineral content (BMC), and lean mass were measured by dual-energy X-ray absorptiometry (DXA) using a Hologic 4500A device, and apparent volumetric BMD (BMAD) of the lumbar spine and the femoral neck were calculated. BMD, BMC, and BMAD were expressed by age groups and Tanner stages for boys and girls separately. There was a significant effect of age and puberty on all bone parameters, except at the femoral neck BMAD in boys. BMC and BMD were higher at cortical sites in boys, including subtotal body and hip; whereas, in girls, it was higher at a site more enriched in trabecular bone, namely the lumbar spine. At several skeletal sites, girls had significantly higher BMD adjusted for lean mass than boys. By the end of puberty, adolescents had a mean BMD that was 43-66% higher at the lumbar spine and 25-41% higher at cortical sites than pre-pubertal children, depending on the gender. Mean BMD values in the study group were significantly lower (P<0.01) than Western normative values, with Z scores ranging between -0.2 and -1.1. In both genders, children of lower socioeconomic status tended to have lower BMD than those from a higher socioeconomic background. This study allows additional insight into gender dimorphism in mineral accretion during puberty. It also provides a valuable reference database for the assessment of BMD in children with pubertal or growth disorders who are of Middle Eastern origin.

Absorptiometry, Photon↗
PubMed2004

Sex differences in the effect of body-composition variables on bone mass in healthy children and adolescents.

BACKGROUND: Prophylactic interventions against osteoporosis require a determination of the factors that influence the accumulation of bone mass during growth. OBJECTIVE: The objective was to determine the independent sex-specific contribution of lean mass and fat mass to bone mineral content (BMC), after adjustment for anthropometric variables and lifestyle factors, in healthy children and adolescents. DESIGN: Healthy schoolchildren (184 boys and 179 girls) aged 10-17 y (x+/- SD: 13.0 +/- 2.1 y) participated in this cross-sectional study. Total and regional (lumbar spine, femoral neck, and distal one-third of the radius) BMC and body composition were measured by dual-energy X-ray absorptiometry. RESULTS: A significant effect of anthropometric variables and lifestyle factors on BMC was observed at all skeletal sites. Lean mass and fat mass showed robust correlations with BMC, even after adjustment for anthropometric variables and lifestyle factors. Lean mass contributed to 6-12% of the variance in BMC in boys and to 4-10% in girls. Fat mass accounted for 0.1-2% of BMC variance in boys and to 0.1-6.5% in girls. CONCLUSIONS: Both lean mass and fat mass are consistent predictors of BMC at multiple skeletal sites in healthy children and adolescents. The contribution of lean mass to BMC variance was larger in boys than in girls. In both sexes, the highest contribution of lean mass to BMC was observed at the femoral neck.

Absorptiometry, Photon↗
PubMed2003

Serum leptin as a determinant of bone resorption in healthy postmenopausal women.

To examine the relationships between serum leptin and bone metabolism, we measured bone mineral density (BMD) at the spine and the hip, fasting serum leptin, and osteocalcin and urinary excretion of C-terminal crosslinking telopeptide of type I collagen (CTX), as markers of bone formation and resorption, respectively, in 121 postmenopausal women aged 54 +/- 5 years. These parameters were also assessed at 6 months and 2 years of treatment with either 2.5 mg tibolone (n = 34), 1.25 mg tibolone (n = 45), or 2 mg estradiol plus 1 mg norethindrone acetate (n = 42). At baseline, serum leptin correlated positively with spine (r = 0.21, P = 0.02) and total hip (r = 0.26, P = 0.0044) BMD and negatively with CTX (r = -0.38, P < 0.0001) and osteocalcin (r = 0.21, P = 0.025). After adjustment for BMI and for fat mass, the association between serum leptin and CTX persisted with a partial correlation coefficient of -0.18 (P = 0.046) and of -0.22 (P = 0.03), respectively. Women in the highest quartile of leptin levels had 11% higher total hip (P = 0.0039) and lumbar spine BMD (P = 0.016), 21% lower osteocalcin (P = 0.01), and 38% lower CTX (P = 0.0005) than women in the lowest quartile (P < 0.05). During treatment, serum leptin levels increased (+14.7 +/- 47.3%, P = 0.019), without significant difference between the groups. This increase correlated with the increase in body weight (r = 0.46, P < 10(-4)). No correlation was found between the changes in leptin and the changes in bone parameters. In conclusion, leptin may play a role as a determinant of bone resorption in healthy, untreated postmenopausal women, but the effect of estradiol or tibolone on bone are not mediated by leptin.

Aged↗