Prevalence of juvenile idiopathic arthritis in children aged 6 to 12 years in Embu das Artes, state of Sao Paulo, Brazil.

The aim of the study was to study the prevalence of juvenile idiopathic arthritis (JIA) in school children in the city of Embu das Artes in São Paulo State. 2880 school children from seven public schools, aged between 6 and 12 years, were evaluated (clinical findings) by a pediatric rheumatologist. A board certified Pediatric Rheumatologist evaluated the subjects with suspected inflammatory arthropathy. Children with higher suspicion were referred to a specialized service. One hundred and forty-one children have presented abnormalities on examination of musculoskeletal system, with isolated pain on palpation the most common finding in the first evaluation (60.9%), with improvement in almost all cases in the second examination. Most of the abnormalities were related to recent injuries or congenital malformations. Six children have clinical findings suggestive of chronic arthropathy and were referred to a specialized pediatric rheumatology clinic. Of these, a 12 year-old girl fulfilled the criteria for JIA. The other diagnoses were aseptic necrosis of the hip (P = 1) of and post-trauma synovitis (P = 4). The prevalence of JIA in children aged between 6 and 12 years was 1/2.880 (or 0.34/1.000).