Joint hypermobility, growing pain and obesity are mutually exclusive as causes of musculoskeletal pain in schoolchildren

Objective: Chronic musculoskeletal pain (MSP) is common in children and can be due to several non-inflammatory conditions such as the benign joint hypermobility syndrome (BJHS), and growing pains (GP). We evaluated frequency, risk factors and causes of MSP in a large cohort of healthy schoolchildren. Methods: We conducted a cross sectional study in a cohort of healthy schoolchildren, aged 8-13 years, by collecting information and performing a physical examination. The anamnesis was focused on family history for MSP, presence and sites of MSP interfering with the regular daily activities during the previous 6 months and presence of GP. Physical examination included body mass index, pubertal stage and musculoskeletal examination focused on the presence of hypermobility according to the Beighton criteria. Results: Two hundred and eighty-nine schoolchildren, 143 females and 146 males, participated in the study. Chronic MSP occurred in 30.4% of subjects, BJHS occurred in 13.2%. GJH was more frequent in symptomatic subjects than in asymptomatic ones (p=0.054). Symptomatic subjects were more frequently pre-pubertal than pubertal (p=0.006). In general, GP, BJHS and obesity (OB) were mutually exclusive as causes of MSP as, among 88 symptomatic subjects, 52.3% had GP, 40.9% presented BJHS, 4.5% were OB and only two (2.3%) presented both BJHS and OB. After puberty, GP persisted in 66.7%, BJHS in 26.7% and in association with OB in 6.7%. Conclusion: Approximately one third of schoolchildren suffer from MSP. BJHS, GP and OB are mutually exclusive as causes of MSP in schoolchildren. Pubertal stage plays an important role in the physiopathology of this condition.