MedWire News: Children with asthma have lower cortisol levels in response to recurrent maternal distress than those without the respiratory condition, researchers have found.

Writing in the Journal of Allergy and Clinical Immunology, Lisa Dreger (University of Manitoba, Winnipeg, Canada) and team explain: “Existing evidence supports associations between exposure to maternal distress and the development of childhood asthma, between exposure to maternal distress and an increased cortisol response in children, and between childhood asthma and an attenuated cortisol response.”

To investigate these associations further, the team analyzed blood samples collected from 503 children, aged 7 to 10 years, after exposure to an acute stressor. In total, 188 had been diagnosed with asthma.

Maternal distress was defined as the diagnosis of a depressive or anxiety disorder, or a prescription history of related medications on the mothers' medical records.

In total, 17 children were exposed to maternal stress only in the first year of life, 221 were exposed to maternal stress only after the first year of life, and 68 were exposed to recurrent maternal stress.

The researchers found that exposure to maternal distress restricted to the first year of life was associated with at least 40% higher cortisol levels, regardless of asthma status, compared with non-exposure.

Recurrent exposure to maternal distress was associated with a 25.9% increase in cortisol levels in children without asthma, but a 5.2% decrease in cortisol levels among those with the respiratory condition, compared with children who were not exposed to maternal distress.

Exposure to maternal distress that occurred only after the first year of life was not associated with elevated cortisol levels, the researchers note.

Dreger and team conclude: “Among children exposed to recurrent maternal distress, an elevation in cortisol levels occurs in response to an acute stressor when there is no accompanying diagnosis of asthma, whereas, in comparison, children with asthma tend to exhibit lower cortisol levels.”

They add: “These findings point to the dysregulation of stress response systems in children with asthma exposed to recurrent maternal distress, supporting the practice of screening for symptoms of distress in new mothers.”

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