Bone mineral density and turnover in non-corticosteroid treated African American children with juvenile rheumatoid arthritis.

OBJECTIVE: To determine bone mineral content (BMC), bone mineral density (BMD), Z scores, and markers of bone turnover in African American children with juvenile rheumatoid arthritis (JRA). METHODS: Eight children with JRA with no prior exposure to corticosteroids were evaluated. Lumbar spine (L1-L4) and total body and total hip BMC and BMD were determined using dual x-ray absorptiometry (DXA), and Z scores (BMD) were calculated. Serum samples of markers of bone turnover including pyridinoline (PYR), N-terminal propeptide of type I procollagen (P1NP), osteocalcin (OC), and bone-specific alkaline phosphatase (BSAP) were measured. RESULTS: The mean Z score (BMD) at the lumbar spine (L1-L4) in patients with JRA was -1.2+/-0.8. Z scores for total body and total hip were within 1 standard deviation of normal compared with healthy historical controls matched for age, sex, and race. CONCLUSION: BMD was normal for chronological age (defined as Z score >or= 2.0) in African American children with JRA who had not previously been treated with corticosteroids. Further studies are needed on the effects of JRA on skeletal health in African American children.

Effects of a low sodium diet on bone metabolism.

Osteoporosis is a serious public health problem, and dietary interventions may potentially be helpful in preventing this disorder. The purpose of this study was to determine the effects of a low sodium diet on bone metabolism in postmenopausal women. This was a longitudinal study to determine the effects of a low sodium (2-g/day) diet on bone. Forty postmenopausal African-American and Caucasian women were enrolled in a 2-g/day sodium diet for 6 months. Sodium and calcium excretion, bone turnover, and calcitropic hormones (intact parathyroid hormone (PTH) and 1,25 dihydroxyvitamin D) were measured before and 6 months after the intervention. In women who had baseline sodium excretions equal to or greater than the average sodium intake in the United States (> or =3.4 g/day), the low sodium diet resulted in significant decreases in sodium excretion (P = 0.01), in calcium excretion (P = 0.01), and in a biomarker of bone turnover, aminoterminal propeptide of type I collagen (P = 0.04). However, there were no significant changes in calcitropic hormones, including intact PTH (P = 0.97) or 1,25 dihydroxyvitamin D (P = 0.49) with the low sodium diet. These findings suggest that in postmenopausal women with sodium intakes > or =3.4 g/day, a low sodium diet may have benefits for skeletal health.