Prevalence of Antinuclear Antibodies in Schoolchildren During Puberty and Possible Relationship with Musculoskeletal Pain: A Longitudinal Study

Objective. The role of antinuclear antibodies (ANA) in children has still to be elucidated. The aim of our study was to evaluate the prevalence and persistence of ANA in schoolchildren during the puberty switch, and the possible relationship with chronic noninflammatory musculoskeletal pain (MSP). Methods. Children aged 8-13 years and attending 4 public schools underwent a clinical examination, focusing on pubertal stage and presence of chronic noninflammatory MSP. Laboratory tests to determine the autoantibody-profile were also performed. Subjects with ANA positivity (titer >= 1:80) and/or chronic noninflammatory MSP were re-evaluated 3 years later. Results. Two hundred sixty-one subjects enrolled in the study and 12.3% were ANA-positive, equally distributed in terms of sex and pubertal stall's. Three years later, in the group of patients studied for chronic noninflammatory MSP (n = 67), ANA positivity significantly increased from 13.4% to 44.8%. In the ANA-positive cohort at baseline (n = 28), 92.9% of subjects were confirmed as being ANA-positive with a significantly increased titer. No association between ANA positivity and chronic noninflammatory MSP was found. Conclusion. ANA prevalence and titers increase during puberty, especially in females, but have no relationship with chronic noninflammatory MSP. This finding may be related to the complex hormonal changes during the puberty switch period and opens new insights into autoimmunity.