Holding babies affects genes: B.C. study

Infants that are held less by caregivers show lasting changes to genes involved in immune response and metabolism, according to a study of children from British Columbia.

Fussy babies who were held the least were underdeveloped for their age in five areas of the genome when they were tested more than four years later. Fussy babies in the high cuddling range were normal. The study also found a “vast” range in the time caregivers spent in contact with the babies, from 200 minutes a day up to about 1,400 minutes, said Michael Kobor, a professor of medical genetics and researcher for B.C. Children’s Hospital Research Institute.

The research involved 96 children who had initially participated as infants in research run by Ronald Barr at B.C. Children’s Hospital.

Parents did not receive instruction on how care for their children, rather, they recorded the duration of contact as it occurred naturally.

Kobor and his colleagues recontacted the families in order to look for molecules that turn up or dampen gene expression like biological “dimmer switches.”

DNA methylation — the addition of molecules of carbon or hydrogen to a sequence of DNA — changes how genes work and affects the function of cells and biological systems.

“There is a huge body of work on animals and human observational studies on contact between caregivers and infants,” said Kobor.

The finding has broad implications for children’s health and psychological development, said lead author Sarah Moore, a post-doctoral fellow.

“If further research confirms this initial finding, it will underscore the importance of providing physical contact,” she said.

The study was published in the journal Development and Psychopathology.