Evolution of bone-mineral density (BMD) in patients with early arthritis. Variation of BMD (ΔBMD) at each site was calculated as described in the Patients and Methods sections. Dotted horizontal line represents the absence of variation in BMD. Data are presented as the interquartile range (p75 upper edge of the box, p25 lower edge, p50 midline in the box), as well as the p95 (upper line from the box) and p5. Dots represent the outliers. Statistical significance was established through the Wilcoxon test for paired samples.