Little is known about the epidemiology of pain in children. We studied the prevalence of pain in Dutch children aged from 0 to 18 years in the open population, and the relationship with age, gender and pain parameters. A random sample of 1300 children aged 0-3 years was taken from the register of population in Rotterdam, The Netherlands. In the Rotterdam area, 27 primary schools and 14 secondary schools were selected to obtain a representative sample of 5336 children aged 4-18 years. Depending on the age of the child, a questionnaire was either mailed to the parents (0-3 years) or distributed at school (4-18 years). Of 6636 children surveyed, 5424 (82%) responded; response rates ranged from 64 to 92%, depending on the subject age and who completed the questionnaire. Of the respondents, 54% had experienced pain within the previous 3 months. Overall, a quarter of the respondents reported chronic pain (recurrent or continuous pain for more than 3 months). The prevalence of chronic pain increased with age, and was significantly higher for girls (P<0.001). In girls, a marked increase occurred in reporting chronic pain between 12 and 14 years of age. The most common types of pain in children were limb pain, headache and abdominal pain. Half of the respondents who had experienced pain reported to have multiple pain, and one-third of the chronic pain sufferers experienced frequent and intense pain. These multiple pains and severe pains were more often reported by girls (P<0.001). The intensity of pain was higher in the case of chronic pain (P<0. 001) and multiple pains (P<0.001), and for chronic pain the intensity was higher for girls (P<0.001). These findings indicate that chronic pain is a common complaint in childhood and adolescence. In particular, the high prevalence of severe chronic pain and multiple pain in girls aged 12 years and over calls for follow-up investigations documenting the various bio-psycho-social factors related to this pain.

This study represents the largest collection of patients with JLS ever reported. The insidious onset of the disease, the delay in diagnosis, the recognition of mixed subtype and the better definition of the other subtypes should influence our efforts in educating trainees and practitioners and help in developing a comprehensive classification system for this syndrome.

Chronic pain, not caused by somatic disease, was present to a higher degree in girls; the pain increased during the day and had a negative impact on quality of life of the adolescents and the family. There is a need for future research aimed at identifying risk factors for chronic pain and pain-associated quality of life in children and adolescents.

Condylar lesions due to arthritis can improve over time, indicating a regenerative capacity of the mandibular condyle. As condylar improvement seems to be associated with low disease activity, it is important to consider the TMJ when deciding on a therapeutic regimen.

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