Girls who are maltreated show higher levels of inflammation at an early age than boys who are maltreated or children who have not experienced abuse, say researchers.

Child maltreatment is behaviour towards a child that is outside the norms of conduct and entails substantial risk of causing physical or emotional harm.

Four types of maltreatment are generally recognized: physical abuse, sexual abuse, emotional abuse (psychological abuse), and neglect.

The study, published in the journal Developmental Psychobiology, may forecast chronic mental and physical health problems in midlife.

The researchers examined the link between abuse and low-grade inflammation during childhood.

Inflammation plays a role in many chronic diseases of aging — diabetes, cardiovascular disease, stroke, obesity — as well as mental health outcomes, and the findings suggest that the maltreatment’s association with inflammation does not lie dormant before emerging in adulthood.

Instead, the study shows that traumatic experiences have a much more immediate impact.

“What our study highlights is that, even as early as childhood, we can see that a substantial portion of the children have levels of inflammation,” said study author Katherine Ehrlich from the University of Georgia in the US.

This suggests that these children may be at risk for significant health problems at an earlier age than their non-maltreated peers.

Participants in the study included 155 children aged 8-12 from low-income backgrounds who attended a weeklong day camp. The sample was racially diverse and included maltreated and non-maltreated children.

Researchers captured detailed information on children’s exposure to abuse.

The children-documented experiences included neglect (55 per cent), emotional maltreatment (67 per cent), physical abuse (35 per cent) and sexual abuse (8 per cent).

Many children experienced more than one type of abuse, and 35 per cent of children experienced abuse across multiple developmental periods.

The team measured five biomarkers of low-grade inflammation using non-fasting blood samples from the children.

Results revealed that childhood maltreatment — for girls — was associated with higher levels of low-grade inflammation in late childhood.

Girls who had been abused over multiple periods or had multiple kinds of exposures had the highest levels of inflammation.

The findings showed that girls’ greatest risk for elevated inflammation emerged when they were abused early in life, before the age of five.

For boys in the study, exposure to maltreatment was not reflected in the higher levels of inflammation, but researchers cautioned against drawing conclusions without additional research targeted to boys.