2Cutolo M, Otsa K, Uprus M, et al. Vitamin D in rheumatoid arthritis . Autoimmun Rev , 2007, 7: 59-64.
3Holick MF. Vitamin D deficiency. N Engl J Med, 2007, 357: 266-281.
4Bischoff-Ferrari HA. Optimal serum 25-hydroxyvitamin D levels for multiple health outcomes. Adv Exp Med Biol, 2008, 624: 55-71.
5Durazo-Arvizu RA, Dawson-Hughes B, Sempos CT, et al. Three- phase model harmonizes estimates of the maximal suppression of parathyroid hormone by 25-hydmxyvitamin D in persons 65 years of age and older. J Nutr, 2010, 140: 595-199.
6Van der Heijde DM. Plain X-rays in rheumatoid arthritis: overview of scoring methods, their reliability and applica-bility. Baillieres Clin Rheumatol, 1996, 10: 435-453.
7Cranney A, Weiler HA, O' Donnell S, et al. Summary of evi- dence-based review on vitamin D efficacy and safety in relation to bone health. Nutr, 2008, 88: 513-519.
8Steven M,Craig MD, Fang YU, et al. Vitamin D status and its associations with disease activity andscverity in African Ameri- cans with recent onset rheumatoid arthritis. J Rheomatol, 2010, 37: 275-281.
9Kerr GS, Sabahi I, Richards JS, et al. Prevalence of vitamin D insufficiency/deficiency in rheumatoid arthritis and associations with disease severity and activity. J Rheumatol, 2011, 38: 53- 59.
10Patel S, Farragher T, Berry J, et al. Association between serum vitamin D metabolite levels and disease activity in patients with early inflammatory polyarthritis. Arthritis Rheum, 2007, 56: 2143-2149.
