PROVIDENCE — Adults who had been neglected as children have DNA that is literally closer to unraveling than adults who had not been mistreated, according to Butler Hospital and Brown University researchers.

The discovery means the effects of childhood neglect can reverberate down to the cellular level, even to the DNA that makes up a person’s genetic code, said Dr. Audrey Tyrka, of Butler, one of the authors of the new study.

The phenomenon was best seen in people who reported physical or emotional neglect. It also appeared in adults who said they had suffered physical or emotional abuse, but the link wasn’t large enough to be statistically significant, she said.

Tyrka said a study larger than the 31 people she tested might find a link there as well.

“When we looked at childhood maltreatment over all, including all types of abuse or neglect, we found it reverberating to the cellular effect and this very basic cellular mechanism,” she said.

DNA has more twists than a platter of spaghetti. To prevent DNA from unraveling, the end of each strand is capped by a telomere, which acts like the protective plastic tip on a shoelace. In Greek, telomere literally means “end part.”

A lot of recent research has suggested that when those telomeres shorten, as they normally do with age, cancer, heart disease or premature aging may result.

“Telomere length is critical to protecting the cell. When telomeres shorten too much, the cell stops replicating. The cell may die or there may be genetic abnormalities that result within the cell,” Tyrka said.

Stress has also been shown to shorten telomeres.

The new study, published online in the journal Biological Psychiatry, is the first to look at the cellular effects of mistreating children.

“We were interested in childhood maltreatment because it’s known to have profound effects in terms of risk for illness and disease, and we know telomere shortening is related to a risk for many of those illnesses,” said Tyrka.

After factors such as chronological age were taken into account, the telomeres of the 10 volunteers who reported that they were mistreated in childhood were about 40 percent shorter than the telomeres of the 21 volunteers who said they had not been abused.

All of the volunteers were healthy and none had a history of psychiatric disorders in spite of the past abuse.

The research was funded by the National Institute of Mental Health and the National Institute of Neurological Disorders.

gemery@projo.com