To conduct a systematic literature review on incidence and prevalence of juvenile idiopathic arthritis and to estimate these figures in Europe for 2010.

Articles on incidence or prevalence of juvenile idiopathic arthritis were searched in Medline. Pooled incidence and prevalence were calculated overall, by gender, age, classification and arthritis categories. We used the available age and gender pooled rates to standardize the incidence and prevalence on the 2010 European population and estimate the number of cases in Europe in 2010.

Forty-three articles (33 on incidence, 29 on prevalence) were included. Incidence rates varied from 1.6 to 23 and prevalence from 3.8 to 400/100,000. Pooled incidence and prevalence were higher for girls (10.0 [9.4–10.7] and 19.4 [18.3–20.6]/100,000) than boys (5.7 [5.3–6.2] and 11.0 [10.2–11.9]/100,000). Oligoarthritis was the most frequent form (pooled incidence rate 3.7 [3.5–3.9] and prevalence 16.8 [15.9–17.7]/100,000). The direct standardized incidence rate was 8.2 [7.5–9.0] and prevalence 70.2 [62.9–78.1]/100,000. In Europe in 2010, the estimated number of incident cases was 6896 [5481–8578] and 59,175 [44,256–76,983] prevalent cases.

Incidence and prevalence varied greatly among published reports of juvenile idiopathic arthritis, which may be explained by methodological issues, classification used, and time. Estimating the number of affected children can be useful, especially with the new treatment possibilities.