Kids' Physical Illnesses May Reflect Parents' Stress

When parents are chronically stressed, it can impair their children's emotional and social functioning, past research has shown. Now it looks as if parents' stress can negatively impact their children's physical health as well, a new study suggests.

The study was headed by Mary Castera, M.D., an associate professor of pediatrics at the University of Rochester. Results appeared in the March Archives of Pediatrics and Adolescent Medicine.

The investigation included 169 children from socioeconomically and racially diverse backgrounds as well as their parents. The youngsters were between 5 and 10 years old and were physically healthy at the time of study enrollment. The parents were assessed every six months for 18 months for family stress events and psychiatric symptoms. Some of the yard-sticks used were the Stressful Life Events and Conditions Checklist, the Brief Symptom Inventory, and the Parenting Stress Inventory.

After the parental assessments, the children were followed for a year to determine whether they got sick and, if so, from what kind of illness. The number of child illnesses for the year ranged from zero to 10, with half of the children having two or fewer illnesses for the year. The number of febrile child illnesses for the year ranged from zero to six, with half the youngsters not having a febrile illness for the year. The most common illnesses by far were upper respiratory tract infections, followed by gastrointestinal tract infections. After that came sinusitis, conjunctivitis, ear infections, strep infections, wheezing/reactive airway disease, and other conditions.

The researchers then looked to see whether the children of parents who had been more stressed and who had experienced more psychiatric symptoms had more physical illnesses than did the children of parents who had been less stressed and who had experienced fewer psychiatric symptoms. They found that to indeed be the case. The children of the former group experienced statistically significantly higher rates of physical illnesses, and especially febrile illnesses, than did the children of the latter group.

The investigators likewise hypothesized that the means by which parents' elevated stress levels and elevated psychiatric symptoms led to physical illnesses in their children occurred via the route of parental stress leading to child stress, and child stress dampening the ability of the child's natural killer cells to fight off infections. So the researchers took blood samples from the children throughout the year after their parents had been assessed, extracted natural killer cells from the samples, and then tested the natural killer cells for their ability to counter infections. The researchers then looked to see whether the natural killer cells from children of the more-impaired parents were less potent than the natural killer cells from children of the less-impaired parents. But to the researchers' surprise, the opposite was the case.

Psychiatric News asked Caserta whether she could explain this unexpected finding. “The increase in natural killer cell function,” she replied, “may be compensating for a separate defect in immune responsiveness that is associated with both stress and illness.” She and her colleagues hope to explore this possibility in a future study, she said.

Meanwhile, she added, “I believe that psychosocial stressors in families may have more wide-ranging public health implications than previously thought and that improving the psychosocial health of the family may reap previously unanticipated benefits.”

The study was funded by the National Institutes of Health.

An abstract of “Association of Family Stress With Natural Killer Cell Activity and the Frequency of Illnesses in Children” is posted at<http://archpedi.ama-assn.org/cgi/content/abstract/161/3/228>.▪