by Nancy Walsh

Children who are irritable or disobedient, or who steal or bully others, are at risk for chronic pain in middle age, a large prospective study found.

Youngsters who had persistent behavior problems at ages seven, 11, and 16 years had more than twice the risk of of widespread chronic pain at age 45 as other children (RR 2.14, 95% CI 1.43 to 3.21), according to Dong Pang, PhD, of the University of Aberdeen, Scotland, and colleagues.

This finding emerged from analysis of data from the 1958 British Birth Cohort Study, the researchers wrote online in Rheumatology.

The study enrolled 18,558 children born during one week in England, Scotland, and Wales in that year, following them prospectively through childhood.

Parents and teachers were asked to describe the children’s behavior on detailed questionnaires at ages seven, 11, and 16. The study subjects were asked for information on psychological distress at age 42 and chronic widespread pain at age 45.

Among other behaviors evaluated were destructiveness, excessive worry, nail-biting, truancy, and restlessness.

The children were stratified according to behavior scores as normal, having mild-to-moderate behavior problems, or having severe problems.

Behavioral assessments were available for 15,303, 14,761, and 12,537 participants at the three childhood time points, and pain assessments were done for 8,572 adults at age 45.

Chronic pain was reported more frequently by women than men (12.9% versus 11.7%).

The risk of chronic pain rose with each unit increase in score on behavior scales as reported by teachers:

* Seven years, RR 1.02 (95% CI 1.01 to 1.02)
* 11 years, RR 1.02 (95% CI 1.02 to 1.03)
* 16 years, RR 1.04 (95% CI 1.03 to 1.05)

The statistical association remained after adjustment for factors including gender, social class, and childhood symptoms.

Children whose behavioral scores were in the mild-to-moderate and severe ranges at age 16, as assessed by teachers, had an increased likelihood of reporting chronic pain in adulthood (RR 1.68, 95% CI 1.38 to 2.06 and RR 1.69, 95% CI 1.18 to 2.42, respectively).

And children with severe behavior disturbances at age 11 had nearly double the risk of chronic pain in adulthood (RR 1.95, 95% CI 1.47 to 2.59).

These elevated risks also remained after accounting for missing values by multiple imputation analysis.

Risk of chronic pain also rose with each unit increase in behavior score as assessed by parents:

* Seven years, RR 1.02 (95% CI 1.01 to 1.04)
* 11 years, RR 1.03 (95% CI 1.01 to 1.05)
* 16 years, RR 1.05 (95% CI 1.03 to 1.06)

The statistical association remained after adjustment for ages 11 and 16 years.

Compared with children with normal scores, those with severe disturbances at 16 as assessed by parents had an increased risk for chronic pain (RR 1.51, 95% CI 1.09 to 2.10).

Previous research has shown that chronic widespread pain in middle-age patients is related to adult behavioral and emotional factors, and also to adverse events in childhood such as separation from mothers.

This study has further demonstrated that maladaptive or maladjusted behavior in early life — particularly when persistent — is associated with chronic pain in middle age.

Strong points of the study include its prospective design, so the analysis is not biased by inaccurate recall of behavior, as can occur in case-control studies.

The study also had no confounding by age and calendar periods.

In addition, behavior was rated by both parents and teachers, and the teachers’ results were slightly stronger.

“In addition to meeting children regularly, teachers are in a unique position to assess each child because they are able to make a comparison with the child’s peers in situations involving varying formal tasks and social demands,” the researchers wrote.

However, potential biases must be taken into account, such as the attrition that occurred over the 45 years of the study and the potential confounding of adult psychological and emotional distress.

Further study will be needed to determine to what extent chronic pain is a manifestation of a poor health trajectory through life, or if there are specific biologic mechanisms involved.

The researchers hypothesized that long-term dysfunction of the hypothalamic-pituitary-adrenal (HPA) axis may play a role.

As the main neuroendocrine stress response system, the HPA axis has been shown to influence both childhood behavior and chronic pain.

Molecular and genetic studies will be needed to clarify this potential association.

“The study of life-course influences on chronic pain is still in its infancy,” the researchers said.

Nancy Walsh is a MedPage Today contributing writer.

Originally published in MedPage Today. Visit MedPageToday.com for more pediatrics news.