Prevalence and risk factors of osteoporosis in patients with Parkinson’s disease

Parkinson's disease (PD) is the most common cause of disability in the elderly. It is currently recognized as a cause of secondary osteoporosis. To evaluate the prevalence of osteoporosis in PD and detect its risk factors, 52 patients with PD (36 men/16 women) and 52 controls paired for age and sex were recruited. Clinical data including demography, disease duration and disease severity were collected. All subjects had bone mineral density (BMD) measured by dual energy X-ray absorptiometry, dorsal and lumbar spine X-ray, and biological exams (osteocalcin, CTX, parathormon). The mean age of the patients was 60.0 +/- 9.25 years [30-77], and the mean disease duration was 4.9 +/- 4.5 years [0.2-17]. Nine patients (17.3%) were osteoporotic and 28 (53.8%) osteopenic. BMD at the lumbar spine and the hip was lower among patients than controls (spine: 1.031 vs. 1.175 g/cm(2); P < 0.001; hip: 0.968 vs. 1.054; P = 0.02). PD patients with low BMD presented a more severe disease and an insufficient sun exposure and calcium intake. There was a positive statistically significant correlation between patients BMD and body mass index and negative correlation with age, severity of PD, and osteocalcin levels. The prevalence of osteoporosis/osteopenia is high in PD patients and seems related to the severity of the disease, an insufficient sun exposure and calcium intake. This osteoporosis constitutes with falls the major risk factors of fracture in PD patients.     

Idiopathic chondrolysis of the hip

Idiopathic chondrolysis of the hip is a rare disease in which gradual necrosis of the hyaline cartilage covering the femoral head and acetabulum leads to joint space narrowing and motion restriction. Pain, motion range limitation, and radiographic joint space narrowing are the main manifestations. We report 2 cases in 15-year-old girls, one black and the other Caucasian. Unexplained pain and motion restriction in the left hip were the presenting manifestations. Narrowing of the hip joint space was noted on standard radiographs. Magnetic resonance imaging showed a joint effusion in 1 patient and unevenness of the femoral head contour in the other. Laboratory tests including microbiological studies were normal or negative. Nonspecific synovitis was found in biopsy specimens. Immobilization and traction were the main components of the treatment strategy.     

Reproducibility of bone mineral density measurements using dual X-ray absorptiometry in daily clinical practice

Bone mineral density (BMD) measurements are frequently performed repeatedly for each patient. Subsequent BMD measurements allow reproducibility to be assessed. Previous studies have suggested that reproducibility may be influenced by age and clinical status. The purpose of the study was to examine the reproducibility of BMD by dual energy X-ray absorptiometry (DXA) and to investigate the practical value of different measures of reproducibility in three distinct groups of subjects: healthy young volunteers, postmenopausal women and patients with chronic rheumatic diseases. Two hundred twenty-two subjects underwent two subsequent BMD measurements of the spine and hip. There were 60 young healthy subjects, 102 postmenopausal women and 60 patients with chronic rheumatic diseases (33 rheumatoid arthritis, 10 ankylosing spondylitis and 10 other systemic diseases). Forty-five patients (75%) among the third group were receiving corticosteroids. Reproducibility was expressed as the smallest detectable difference (SDD), coefficient of variation (CV), least significant change (LSC) and intraclass correlation coefficient (ICC). Sources of variation were investigated by linear regression analysis. The median interval between measurements was 0 days (range 0–7). The mean difference (SD) between the measurements (g/cm²) was –0.0001 (±0.003) and –0.0004 (±0.002) at L1-L4 and the total hip, respectively. At L1-L4 and the total hip, SDD (g/cm²) was ±0.04 and ±0.02, CV (%) was 2.02 and 1.29, and LSC (%) 5.60 and 3.56, respectively. The ICC at the spine and hip was 0.99 and 0.99, respectively. Only a minimal difference existed between the groups. Reproducibility in the three groups studied was good. In a repeated DXA scan, a BMD change, the least significant change (LSC) or the SDD should be regarded as significant. Use of the SDD is preferable to use of the CV and LSC because of its independence from BMD and its expression in absolute units. Expressed as SDD, a BMD change of at least ±0.04 g/cm² at L1-L4 and ±0.02 g/cm² at the total hip should be considered significant. This reproducibility seems independent from age and clinical status and improved in the hips by measuring the dual femur.     

Bone Mineral Density of the Spine and Femur in Healthy Moroccan Women

Bone mineral density (BMD) measurements using dual-energy X-ray absorptiometry (DXA) are widely used to diagnose osteoporosis and assess its severity. Previous studies show the necessity to establish reference data for bone mass measurements for each particular population. Such data are lacking for the Moroccan population. The aim of this study was to determine spine and femur BMD reference values for the Moroccan female population and to compare them with values from western and other Arab countries. A cross-sectional study of 569 Moroccan women, (randomly selected in the area of Rabat, the capital of Morocco, aged between 20 and 79 yr) was carried out to establish reference values of BMD. Measurements were taken at the lumbar spine and proximal femurs using DXA (Lunar Prodigy Vision, GE). The data were compared with published normative data taken by United States (U.S.), European, Kuwaiti, Lebanese, and Saudi women over 6 decades of age. The percentage of osteoporosis in postmenopausal women using our reference curve was compared to that observed when the other curves (US, European and Arab) implemented in the Lunar machine was used. Our results showed that the Moroccan women showed the expected decline in BMD at both sites with age after peaking at 20–29 years of age. Moroccan females have lower BMD at the spine than U.S., Europeans, and Kuwaitis (approximately 10–12% for patients older than 50 yr). The BMD values of the total femur in Moroccan females were close to western (European and American), and Kuwaitis, but higher than Lebanese and Saudis. Using our reference database, 37.9% of postmenopausal women had spine osteoporosis vs. 39.6% and 23.4% using US/European and Arabic Lunar reference values respectively. At the femurs, 6.7% had osteoporosis vs. 2.5% using the Arabic Lunar reference values. In conclusion, our study emphasizes the importance of using population-specific reference values for BMD measurements to avoid over or underdiagnosis of osteoporosis.     

Monitoring of dual-energy X-ray absorptiometry measurement in clinical practice.

Bone densitometry has become the "gold standard" in osteoporosis diagnosis and treatment evaluation. It has also become more and more common to perform a second dual-energy X-ray absorptiometry (DXA) measurement to monitor bone mineral density (BMD) status or the effect of therapeutic intervention. When a second measurement is performed on a patient, the clinician needs to distinguish between a true change in BMD and a random fluctuation related to variability in the measurement procedure. The reproducibility of DXA measurements is claimed to be good. Such variability is due to multiple causes, such as device errors, technician variability, patients' movements, and variation due to other unpredictable sources. The precision error is usually expressed as the coefficient of variation (CV). However, several other statistics to express reproducibility exist such as the smallest detectable difference (SDD) or the least significant change (LSC). The SDD represents a cut-off that can be measured in an individual and is usually considered more useful than the CV in clinical practice. Indeed, the use of the SDD is preferable to the use of the CV and LSC because of its independence from BMD level and its expression in absolute units (g/cm2). At each measurement center, the SDD must be calculated from in vivo reproducibility data. The choice of the optimum time and site for performing follow-up scans depends on the ratio of the expected BMD treatment effect to the precision of the measurements.