Serum levels of pyridinium crosslinks in postmenopausal women and in Paget's disease of bone.

The purpose of this study was to measure pyridinium crosslinks in serum by high performance liquid chromatography (HPLC) and to correlate levels with urinary excretion in patients with different osteometabolic conditions. Blood and spot urine samples were collected between 9 and 11 A.M. in 92 early postmenopausal, untreated women (age 52.3 +/- 2.6 years, months since menopause 20.4 +/- 9.6), 17 patients with active Paget's disease (10 males, aged 65. 1 +/- 12.6) and 24 healthy premenopausal women (aged 28.4 +/- 4.2). Urinary excretion of the total fraction (free + peptide bound) of pyridinolines (Pyr, Dpyr) was measured by HPLC. Before HPLC analysis, serum samples were submitted to a clean-up procedure by ultrafiltration. In 42 postmenopausal women, bone loss was calculated from two bone mass measurements (L2-L4, DXA), performed at study entry and after 12 months. Statistical analysis was performed by Student's t test for independent samples and linear regression analysis. In pagetic patients' serum levels of Pyr and Dpyr were more than threefold increased over the mean observed in healthy controls and were closely correlated with total alkaline phosphatase levels (Pyr: r = 0.73; Dpyr: r = 0.72, P < 0.0005). Compared with controls, postmenopausal women had significantly increased levels of both urinary and serum Pyr and Dpyr (P < 0.003). In pagetic patients and postmenopausal women, crosslinks serum levels were correlated with their urinary excretion with r values ranging from 0.46 to 0.84. In postmenopausal women, only serum Dpyr correlated with the rate of bone loss (r = -0.36, P = 0.02). The data suggest that serum levels of pyridinium cross-links are correlated with urinary excretion in patients with different osteometabolic conditions. The determination of serum levels prevents limitations related to urinary specimen collection and may be a more practical method for routine application, avoiding corrections for urinary creatinine which could be misleading.

Is the metatarsal fracture in postmenopausal women an osteoporotic fracture? A cross-sectional study on 113 cases.

To evaluate whether metatarsal fracture in postmenopausal women can be related to osteoporosis, a sample of 113 postmenopausal women with metatarsal fracture due to minor trauma were recruited. Demographic and clinical data were compared with a control group of 339 healthy age-matched women and with a sample of 224 women with wrist fracture. In all women, bone mineral density (BMD) was measured at the lumbar spine by dual-energy X-ray absorptiometry. The average age of the metatarsal fracture group was slightly lower than that of the wrist fracture group (56.9 vs 58.4 years). Women with metatarsal and wrist fracture had a significantly higher age at menarche, lower age at menopause and lower body mass index when compared with controls. In both fracture groups BMD was significantly lower compared with controls. In stepwise logistic regression models, factors associated with metatarsal fracture risk were age at menopause (odds ratio [OR] 0.86; 95% confidence interval [CI] 0.81-0.92) and BMD (OR per -1 SD 2.44; CI 1.92-3.11). Factors associated with wrist fracture risk included age at menopause (OR 0.89; CI 0.84-0.93) and BMD (OR per -1 SD 2.65; CI 2.17-3.24). The similarities existing in risk factors and their estimates between a well-recognized osteoporotic fracture such as wrist fracture and metatarsal fracture, support the hypothesis that the latter can be included among osteoporotic fractures.

Transient osteoporosis of the hip: a densitometric study.

Three new cases of transient osteoporosis of the hip are reported. Diagnosis was achieved by plain radiographs, bone scintiscan, magnetic resonance imaging and X-ray absorptiometry of proximal femurs. The densitometry showed at the Ward's triangle a mean reduction of bone mineral density in the affected side of 36%. All subjects were treated with i.v. clodronate for ten consecutive days with a complete recovery of femoral density within 4 months. X-ray absorptiometry allows a quantification of the demineralization process and can be useful in the long term evaluation of this entity.

Evaluation by dual-photon absorptiometry of bone mineral loss in rheumatic children on long-term treatment with corticosteroids.

The introduction of reliable and non-invasive methods of measuring bone mass has allowed investigators to study the bone mass loss (ostopenia) related to rheumatic diseases and corticosteroid therapy. Serial measurements of lumbar bone mineral density (BMD) by dual-photon absorptiometry (DPA) is an effective method of checking bone mineralisation. In children, however, the bone mass is not constant over time, so bone densitometric measurements must take into account not only the net loss but also the missing increase in BMD. In order to study the effects of both chronic rheumatic disease and the long-term administration of corticosteroids in children, as a first step the reference curves of bone mineralisation (mean BMD values and annual % BMD growth rates) were calculated from a control population of 79 children (32 males and 47 females) aged 3 to 20 years. All the subjects involved in the study underwent DPA utilising a Norland Bonestar instrument provided with a 153 Gadolinium source and the average BMD (g/cm2) of the lumbar spine was calculated. As a second step, a transverse study was carried out on a series of 157 children and young adults affected by chronic rheumatic diseases with juvenile onset. As a third step, a longitudinal study on the adverse effect of the chronic administration of corticosteroids on bone mineralisation was carried out on a series of 58 patients affected by chronic rheumatic diseases with juvenile onset who were being treated with long-term corticosteroids. Serial measurements of bone mass should help us to improve our strategies in preventing and counteracting osteopenia due to the chronic administration of corticosteroids also in children.