Table 1.

Randomized controlled trials included in the systematic review of the effects of vitamin D supplementation on rheumatoid arthritis.

References	Sample	Mean age	Nation	Supplemented	Supplementation	Time of	Outcome	Adverse event;
	size	(T/C)	(T/C)	dose of vitamin D		intervention	measured	follow-up
Salesi and Farajzadegan (17)	50/48	49.9 ± 13/50 ± 12.7	Iran	50,000 IU/weekly	Vit D	12 week	①②③④⑤⑥	No
Gopinath and Danda (18)	59/62	44.86 ± 12.33/44.90 ± 12.5	India	500 IU/weekly	Vit D + Ca	12 week	④⑤⑥⑧	No
Hansen et al. (19)	11/11	63 ± 12/53 ± 11	America	50,000 IU/weekly	Vit D	12 week	①⑨	No
Buondonno et al. (20)	18/18	56 ± 14/54 ± 12	Italy	300,000 IU/day	Vit D	12 week	④⑤⑥⑧⑨	No
Adami et al. (21)	51/51	58 ± 13/58 ± 12	Italy	100,000 IU/4 weeks	Vit D	12 week	①②③⑤⑦	No
Soubrier et al. (22)	29/30	59.8 ± 10.9/59.7 ± 8.9	France	100,000 IU once	Vit D	24 week	④⑤⑥⑧	No

Months were converted to weeks by using 1 mo = 4 wk; years were converted by using 1 y = 52 wk.

T, treatment group; C, control group; DAS28, Disease Activity Score 28; VAS, Pain visual analog scale; TJC, Tender joint count; SJC, Swollen joint count; ESR, Erythrocyte sedimentation rate; CRP, C-reactive protein; PTH, Parathyroid hormone.

① Serum vitamin D Level; ② Tender joint count; ③ Swollen joint count; ④ ESR; ⑤ VAS (0–100); ⑥ DAS 28; ⑦ DAS 28-CRP; ⑧ CRP; PTH.