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.

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.

The aim of this study was to test the reliability and validity of the COMFORT scale as a postoperative pain instrument for children aged 0-3 years. Subjects were 158 neonates and toddlers after major abdominal or thoracic surgery. Trained nurses rated the children's pain at 3, 6 and 9 h postoperative on the Pediatric Surgical Intensive Care Unit using the COMFORT and a VAS for pain. Interrater reliability of the COMFORT items proved to be good (Kappa 0.63-0.93) for all items with the exception of the item 'Respiratory response', which was moderate (Kappa 0.54). LISREL analyses showed that the structure of the COMFORT data was best represented by three latent variables: COMFORT 'behaviour' with loadings from the behavioural items (Alertness, Calmness, Respiratory response/Crying, Physical movement, Muscle tone and Facial tension) and separate latent variables for 'Heart rate baseline' (HR) and 'Mean arterial blood pressure baseline' (MAP). Factor loadings of the items were invariant across time, indicating stability of the structure. The latent variables COMFORT 'behaviour' and VAS pain were highly interrelated indicating congruent validity. Stability of COMFORT 'behaviour' and VAS pain was moderate which might be due to varying painful episodes in this sample. HR and MAP, although stable across time, were weakly related to VAS pain and COMFORT 'behaviour'. These findings support the use of the COMFORT 'behaviour' scale to assess postoperative pain in neonates and infants.

Both patients and their partners demonstrated high levels of anxiety and distress in the early period after the diagnosis. These findings indicate careful attention by health care professionals to identify those who may benefit from further psychological support.