To evaluate the influence of hydration status on the estimation of body composition using dual-energy X-ray absorptiometry (DXA), six normal volunteers and seven patients on maintenance haemodialysis were investigated using two different DXA machines (Lunar DPX, Hologic QDR 1000/W). Normal volunteers were studied (Hologic QDR 1000/W) before and 1 h after ingestion of breakfast, lunch and dinner (drinking various amounts of liquids at each meal, 0.5-2.4 kg). Whereas bone mineral content and body fat mass did not change, lean body mass of the trunk increased as a consequence of the meals. Conversely in patients on haemodialysis (Lunar DPX), lean body mass decreased in all segments of the body as a consequence of removal of 0.9-4.4 kg of salt-containing fluid by haemodialysis (trunk 61%, legs 30%, arms 5.5% and rest of the body 3.5%), whereas bone mineral content and body fat mass remained unchanged. However, this finding(s) did not hold true in one particular patient with bilateral hip prostheses. Measurement of body composition in eight normal volunteers on the same day with both machines showed similar results for lean and fat mass, whereas bone mineral content was found to be 17% higher using the Lunar DPX. In summary, in centres where both machines are available, follow-up of one individual patient should always be performed using the same equipment. In addition, hydration status and food intake must be taken into account when repetitive measurements of lean body mass are performed in the same patient.

To assess bone mineral density (BMD) in idiopathic calcium nephrolithiasis, dual-energy x-ray absorptiometry was performed at lumbar spine, upper femur (femoral neck, Ward's triangle, and total area), distal tibial diaphysis, and distal tibial epiphysis in 110 male idiopathic calcium stone formers (ICSF); 49 with and 61 without hypercalciuria on free-choice diet). Results were compared with those obtained in 234 healthy male controls, using (1) noncorrected BMD, (2) BMD corrected for age, height, and BMI, and (3) a skeletal score based on a tercile distribution of BMD values at following four sites: lumbar spine, Ward's triangle, tibial diaphysis, and tibial epiphysis. After correction, BMD--and therefore also skeletal score--tended to be lower in the stone formers than in controls at five of the six measurement sites, that is, lumbar spine, upper femur, Ward's triangle, tibial diaphysis, and tibial epiphysis, limit of significance being reached for the last two sites without difference between hypercalciuric (HCSF) and normocalciuric stone formers (NCSF). Estimated current daily calcium intake was significantly lower in patients (616 +/- 499 mg/24 h, mean +/- SEM) than in controls (773 +/- 532, p = 0.02). Of 17 patients who in the past had received a low-calcium diet for at least 1 year, 10 had a low skeletal score (4-6) whereas only 1 had a high score (10-12; p = 0.037). Of the 12 stone formers in the study with skeletal score 4 (i.e., the lowest), 8 had experienced in the past one or more fractures of any kind versus only 19 of the remaining 77 patients with skeletal score 5-12 (p = 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)

High cumulative prednisone doses are deleterious for the axial skeleton. Low levels of PTH observed 1 week after kidney transplantation are predictive of continuous cortical bone loss.

Renal transplant patients exhibit increased rates of trabecular bone fractures, probably due to glucocorticoid-induced osteopenia, which is known to occur within 6 months after kidney grafting. This mineral loss at a mostly trabecular site (lumbar spine) contrasts with a gain at the radius, which consists mainly of cortical bone. However, the early effects of kidney transplantation on the other parts of the human skeleton and the time course of these changes during the first 5 months after transplantation remain unknown. Therefore, 34 kidney transplant recipients were prospectively followed immediately after kidney grafting (12 +/- 1 days, mean +/- SEM, and then on a monthly basis up to 152 +/- 3 days) and compared with 34 normal healthy volunteers matched for age, sex, and body mass index. Bone mineral measurements of whole body (n = 34), lumbar spine (n = 32), and upper femur (n = 23) were performed using dual-energy x-ray absorptiometry (Hologic QDR 1000W). At time of transplantation, lumbar bone mineral density (BMD) and BMD of the upper femur were lower (p < 0.01) in female but not male patients compared with controls. Lumbar BMD decreased by 1.6 +/- 0.2% per month in both sexes (p < 0.01), whereas BMD of upper femur further decreased in males (p < 0.01) but only tended to decrease in females. At time of transplantation, whole-body bone area (BA), bone mineral content (BMC), and BMD were decreased by about 8, 15, and 9%, respectively, in patients compared with controls (p < 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)

Approximately one third of ICSFs with or without so-called MMH are sensitive to meat protein in terms of oxalate excretion, as opposed to healthy subjects. Mechanisms underlying this sensitivity to meat protein remain to be elucidated and do not seem to involve vitamin B(6) deficiency.