Poor quality care and long hours may alter children’s genetic maps

Researchers from the University of Exeter have found that increased levels of the stress hormone cortisol in babies and small children when separated from their parents, especially their mothers, may have “a long term genetic impact on future generations.”

In a commentary published by the Journal of the Royal Society of Medicine, the authors say that several studies show that small children cared for outside the home, especially in poor quality care and for 30 or more hours per week, have higher levels of cortisol than children who are cared for at home.

While cortisol release is a normal response to stress in mammals facing an emergency, sustained cortisol release over hours or days can be harmful, Professor Sir Denis Pereira Gray, Emeritus Professor of General Practice at the University of Exeter, who wrote the paper with two colleagues, said.

Raised cortisol levels are a sign of stress, something which Professor Gray said has been associated with children, particularly boys, acting aggressively. Not all children are affected, he said, but “an important minority” are. 

Raised cortisol levels are associated with reduced antibody levels and changes in those parts of the brain which are associated with emotional stability.

“Environmental factors interact with genes, so that genes can be altered, and once altered by adverse childhood experiences, can pass to future generations. Such epigenetic effects need urgent study”, the authors said.

Professor Gray would like to see future researchers explore the links between the care of small children in different settings, their cortisol levels, DNA, and behaviour.

The research, and associated commentary, may be viewed here.