Fig. 1

Concentrations of serum 25OHD levels across diagnostic groups where levels were available at baseline. Boxes represent median and interquartile range (IQR), whiskers represent the range, and beyond this any extreme outlier values are also shown. Values for each group are as follows: (i) rheumatoid arthritis (RA), n = 335, median 46.7, IQR 30.0–73.0; (ii) undifferentiated inflammatory arthritis (UIA), n = 130, median 51.5, IQR 30.0–72.7; (iii) clinically suspect arthralgia (CSA), n = 156, median 47.7, IQR 30.3–73.0; (iv) other forms of arthritis (Other) n = 102, median 39.9, IQR 28.6–62.2