Trajectories of pain in adolescents: a prospective cohort study.

Identification of different patterns of change in pain over time - trajectories - has the potential to provide new information on the course of pain. Describing trajectories among adolescents would improve understanding of how pain conditions can develop. This prospective cohort study identified distinct trajectories of pain among adolescents (11-14 years) in the general population (n=1336). Latent class growth analysis was carried out on the self-reported frequency of back pain, headache, stomach pain and facial pain, which was collected every 3 months for 3 years. Forty four percent of adolescents had a 'painful' trajectory for at least one pain site, and 12% reported persistent pain at one or more pain site. Headache was the most common; 25% of subjects were in a 'painful' trajectory and 5% reported persistent pain. Back pain and stomach pain were also common, with 22% and 21% of subjects in painful trajectories, respectively. Facial pain was the least common, with only 10% in a painful trajectory, and 1% reporting persistent pain. Trajectory characteristics were similar at baseline across pain sites, with the more painful trajectories having significantly higher levels of depression and somatization, lower life satisfaction and more females. Trajectories did not differ significantly at baseline in physical activity levels or BMI. Agreement of trajectory membership among pain sites was moderate. In summary, reporting a painful trajectory was common among adolescents, but persistent pain was reported by a small minority, and was usually experienced at a single pain site.

Graded chronic pain status: an epidemiologic evaluation.

In epidemiologic research on chronic pain, differentiation of recurrent, persistent and disabling pain states is critical in the investigation of burden, natural history, effective intervention and causal processes. We report population-based data concerning the development and evaluation of a graded classification of pain status. In a probability sample of 1016 health maintenance organization enrollees, recurrent or persistent pain was observed in 45%; severe and persistent pain in 8%; severe and persistent pain with 7 or more days of pain-related activity limitation in 2.7%; and severe, persistent pain with activity limitation and 3 or more indicators of pain dysfunction in 1.0% of the population sample. Graded chronic pain status was associated with psychological impairment, unfavorable appraisal of health status, and frequency of use of pain medications and health care. The presence of severe and persistent pain increased the likelihood of multiple indicators of pain dysfunction, but there was considerable heterogeneity in pain dysfunction among persons with comparable pain experience. Our data suggest grading chronic pain in terms of 3 axes: time (persistence); severity; and impact (disability and dysfunctional illness behaviors).

An epidemiologic comparison of pain complaints.

A survey concerning common pain conditions and psychological distress was carried out among a probability sample of the adult enrollees of a large health maintenance organization in Seattle. The prevalence of pain in the prior six months was 41% for back pain; 26% for headache; 17% for abdominal pain; 12% for chest pain; and 12% for facial pain. Headache, abdominal and facial pain were less prevalent among older persons and more prevalent among females. We examined the temporal dimensions of these pain conditions, as well as intensity, treatment seeking, and activity limitation. The pain conditions were typically long standing, recurrent, of mild to moderate intensity, and usually did not limit activities. However, depending on the pain condition, 9-40% reported one or more days in the prior six months when they were unable to carry out their usual activities due to the pain problem. On average, persons with a pain condition had higher levels of anxiety, depression, and non-pain somatic symptoms as measured by the scales of the Symptom Checklist (SCL); poorer self-rating of health status; and more family stress compared to persons without a pain condition. Of these alternative measures of distress, the SCL somatization scale had the strongest independent association with pain. The increments in measures of anxiety, depression, and family stress with the presence of pain were greatest among persons with higher levels of non-pain somatic symptoms.