Fibroblast growth factor 23 contributes to diminished bone mineral density in childhood inflammatory bowel disease.

BACKGROUND: Diminished bone mineral density (BMD) is of significant concern in pediatric inflammatory bowel disease (IBD). Exact etiology is debatable. The recognition of fibroblast growth factor 23 (FGF23), a phosphaturic hormone related to tumor necrosis factor alpha (TNF-α) makes it plausible to hypothesize its possible relation to this pathology. METHODS: In this follow up case control study, BMD as well as serum levels of FGF23, calcium, phosphorus, alkaline phosphatase, creatinine, parathyroid hormone, 25 hydroxy vitamin D3 and 1, 25 dihydroxy vitamin D3 were measured in 47 children with IBD during flare and reassessed in the next remission. RESULTS: Low BMD was frequent during IBD flare (87.2%) with significant improvement after remission (44.7%). During disease flare, only 21.3% of patients had vitamin D deficiency, which was severe in 12.8%. During remission, all patients had normal vitamin D except for two patients with Crohn's disease (CD) who remained vitamin D deficient. Mean value of serum FGF23 was significantly higher among patients with IBD during flare compared to controls. It showed significant improvement during remission but not to the control values. 1, 25 dihydroxy vitamin D3, FGF23, serum calcium and urinary phosphorus were significant determinants of BMD in IBD patients. CONCLUSIONS: We can conclude that diminished BMD in childhood IBD is a common multifactorial problem. Elevated FGF23 would be a novel addition to the list of factors affecting bone mineral density in this context. Further molecular studies are warranted to display the exact interplay of these factors.

Bone mineral density changes in patients with recent-onset rheumatoid arthritis.

BACKGROUND: Osteoporosis and related fragility fractures are one of the most common complications seen in patients with rheumatoid arthritis (RA) and dramatically affect quality of life. OBJECTIVE: To evaluate changes in bone mineral density in patients with recent onset rheumatoid arthritis (<1 year) and its correlation if any with a modified DAS-28 score and simple erosion narrowing score (SENS). METHODS: This study included 30 patients with recent-onset rheumatoid arthritis fulfilling the new American College of Rheumatology/European League Against Rheumatism diagnostic criteria for rheumatoid arthritis and 20 healthy volunteers as controls. All were subjected to a complete blood count, erythrocyte sedimentation rate, C-reactive protein, liver function tests, renal function tests, rheumatoid factor, and plain x-rays of the hands and feet. Dual-energy x-ray absorptiometry DEXA was used to measure bone mineral density (BMD) of the left proximal femur, lumbar spine (L1-L4), and lower distal radius at the time of recruitment. RESULTS: In the RA patients, 13.3% had osteoporosis, 50% had osteopenia, and 36.7% had normal BMD. The most common site of osteoporosis was the lumbar spine (four patients, 13.3%) followed by the femur (two patients, 6.6%), and forearm (only one patient, 3.3%). There was a significantly higher percentage of osteoporosis among RA males than females and the difference was statistically significant (P = 0.009). Osteoporosis was more common in patients treated with corticosteroids and disease modifying antirheumatic drugs (DMARDs) than in patients treated with only nonsteroidal anti-inflammatory drugs (P = 0.004). Higher disease activity (DAS-28) was found in RA patients with osteoporosis compared to RA patients with normal BMD or osteopenia, but the difference was not statistically significant. Osteoporotic RA patients were found to have a higher SENS score for radiological damage than nonosteoporotic ones. CONCLUSION: BMD changes do occur in patients with early RA, and are not necessarily correlated with disease activity (DAS-28). However, a significant negative correlation was found between BMD and the score of radiological damage (SENS). Dual energy x-ray absorptiometry is an important investigation to assess BMD in early RA patients.