Stress and adversity early in life may lead to long-term health problems and early death, a group of psychologists warn.

New studies suggest that childhood stress caused by poverty or abusive childhoods can lead to heart disease, inflammation and speed up cell aging.

The American psychological Association meeting heard that early experiences “cast a long shadow” on health.

One expert in the UK said that more evidence was suggesting a physical impact of stress in childhood.

In one specific study, researchers from the University of Pittsburgh looked at living in poverty and its relationship to early signs of heart disease in 200 healthy teenagers.

They discovered that the subjects from the families that were worst-off had stiffer arteries and higher blood pressure.

Another piece of research by the same team showed that kids from poorer homes were more likely to interpret a series of mock social situations as a threat.

They found higher blood pressure and heart rates and higher hostility and anger scores during the laboratory stress tests.

The new findings back other research that shows a causal link between a stressful childhood and future cardiovascular disease, said study leader Professor Karen Matthews.

She said that unpredictable an stressful environments lead children to be “hyper vigilant” to threats.

"Interactions with others then become a source of stress, which can increase arousal, blood pressure, inflammation levels and deplete the body's reserves.

"This sets up risk for cardiovascular disease."

Another study said that childhood events like the death of a parent or abuse can make people more vulnerable to the effects of stress in later life and shorten lifespans.

Ohio State University looked at older adults, some of whom were carers for people with dimensia.

They measured several markers of inflammation in the blood which can show stress, as well as length of telomeres, protective caps in the ends of chromosomes which have been linked to age related disease.

The 132 subjects then answered a questionnaire on depression and past child abuse and neglect.

A third study showed some sort of physical, emotional or sexual abuse during childhood.

Those who did face adversity as kids had shorter telomeres and increased levels of inflammation even after controlling for age, care-giving status, gender, body mass index, exercise and sleep.

Study leader Professor Janice Kiecolt-Glaser, said, "Our latest research shows that childhood adversity casts a long shadow on one's health and can lead to inflammation and cell ageing much earlier than for those who haven't experienced these events.

"Those reporting multiple adversities could shorten their lifespan by seven to 15 years," she added.

Dr Andrea Danese, who is a clinical lecturer at the Institute of Psychiatry in London, said that such studies had to be viewed carefully because there is a chance that people do not recall their childhoods as accurately as some and you can only show an association not prove causality.

"But that doesn't mean I don't believe these results.

"The evidence is quite consistent.

"It's already been established that childhood stress has an effect on mental health and it now seems like it has an enduring effect on physical health."

He said that stress causes an increase in inflammatory proteins which could underpin the physical consequences suggested by the research.