Vitamin D deficiency in rheumatoid arthritis: prevalence, determinants and associations with disease activity and disability

Table 2 Mean and frequency of 25(OH)D values lower than 20 or 30 mg/ml according with ranges of vitamin D supplementations

D3 supplementation IU/day	N.	25(OH)D ng/ml mean (S.D.)	25(OH)D < 20 ng/ml (%)	25(OH)D < 30 ng/ml (%)
None	654	21.0 (10.2)	51.8%	84.4%
≤ 440	196	26.1 (12.4)	33.2%	74.5%
≥800	318	29.2 (18.5)	31.4%	63.5%
Controls	1,019	19.3 (14.3)^a	65.0% ^a	80.6% ^b

^a = P < 0.01 and ^b = P < 0.05 versus supplemented RA patients.
Abbreviations: 25(OH)D (25-hydroxyvitamin D).
All differences (both proportions and means) across the three ranges of vitamin D supplementation in RA were statistically significant.

ISSN: 1478-6362