Bone mineral density in juvenile onset systemic lupus erythematosus.

OBJECTIVE: To compare bone mineral density in patients with juvenile-onset Systemic lupus erythematosus and healthy controls. PARTICIPANTS: Serial bone mineral density measurements in 27 patients with juvenile-onset systemic lupus were compared to 97 healthy age-matched controls. RESULTS: All patients with juvenile-onset had low bone mineral density scores at initial assessment that progressed over disease course. Low body mass index was independently associated with a decline in bone mineral density Z scores; disease activity, use of immunosuppressive agents and vitamin D levels were not risk factors. CONCLUSIONS: Patients with juvenile-onset systemic lupus erythematosus have low bone mineral density.

Decreased bone mineral density in prepubertal children with sickle cell disease: correlation with growth parameters, degree of siderosis and secretion of growth factors.

Patients with sickle cell disease (SCD) frequently have bone disorders of multifactorial aetiology. We attempted to analyse the relationships between bone mineral density (BMD) on the one hand and auxologic parameters, degree of siderosis, function of the growth hormone (GH)/insulin-like growth factor-I (IGF-I)/IGF-binding protein 3 (IGFBP3) axis, and calcium-phosphate balance in 28 prepubertal children with SCD and 15 age-matched children with constitutional short stature (CSS). Children with SCD had significantly decreased BMD (77.9 +/- 11.9 per cent of normal BMD for age and sex) and circulating concentrations of IGF-I (91 +/- 31 ng/ml) and IGFBP3 (1.7 +/- 0.44 mg/l) compared with the control group (BMD = 93.5 +/- 8.2 per cent of normal BMD for age and sex, IGF-I = 221 +/- 48 ng/ml, and IGFBP3 = 2.3 +/- 0.34 mg/ml). GH response to provocation was defective (peak below 10 micrograms/l) in 40 per cent of children with SCD. Those with SCD with defective GH secretion had significantly lower circulating IGF-I concentration and BMD than those with normal GH secretion. Serum calcium, phosphate and alkaline phosphatase concentrations were normal in all children with SCD. BMD was correlated significantly with height, weight, and body mass index as well as with the circulating concentrations of IGF-I and IGFBP3. It is suggested that increasing the circulating IGF-I concentration, either through increasing the caloric intake of subjects and/or via GH/IGF-I therapy, may improve growth and bone mineralization in these patients.

Multiparity and bone mass.

OBJECTIVE: To investigate the influence of multiparity on bone mass of the axial skeleton in a population of women of high parity. DESIGN: Open study of Omani women. SETTING: Medical physics department and clinical physiology department of a third degree referral (university) hospital. PARTICIPANTS: A consecutive series of 159 normal women referred with low back pain over a period of six months. RESULTS: The bone mineral density was measured with dual-photon absorptiometry and the mean was found to be 0.984 (+/-0.166) (+/- SD) g cm-2. The age ranged from 20 to 70 years with a mean age of 43.4 (+/- 12.5) years. The number of children per woman ranged from 0 to 14 with a mean of 5.1 (+/- 3.5). There was no statistically significant influence of the number of children per woman on bone mineral density but there was a strong correlation with age and body size variables. CONCLUSION: Multiparity does not influence lumbar spine bone mineral density in normal women.

Z-transform method for deconvolution as applied to the renogram.

A method of deconvolution analysis involving the use of the z-transform has been developed. When compared to the matrix method, it is shown, under certain circumstances, to be identical. In order to study the validity of the method, simple mathematical models have been constructed. The curves obtained with the computed method closely fitted those obtained by mathematical analysis. The z-transform algorithm was applied to clinical data in order to demonstrate its validity for the deconvolution of renograms. The advantages of the method over the matrix method are discussed.

A study of bone mineral density versus age in Omani women and a comparison with normal British women.

Dual photon absorptiometry (DPA) of the lumbar spine (2nd, 3rd and 4th lumbar vertebrae) was carried out using a Norland 2600 bone densitometer on 194 Omani women (OW). The exclusion criteria were (1) any medical treatment known to affect calcium metabolism or bone mass, (2) osteomalacia or secondary osteoporosis, (3) the presence of osteophytes or compression fractures of the lumbar vertebrae and (4) the presence of aortic calcifications. The bone mineral density (BMD) results showed a peak value occurring in the 30-35 year old age range (mean 1.1 g cm-2, standard deviation 0.1). The data were compared with a group of 165 normal British women (BW) with a similar age distribution whose peak BMD (obtained with dual X-ray absorptiometry) occurred in the 40-45 year old age range. The two groups were compared in each 10 year age range and the BMD of the OW group was found to be significantly lower in the 40-49 year old age range (P < 0.01) as well as the 50-59 and 60-69 year old age ranges (P < 0.001).