The effects of childhood abuse and lack of parental affection can last a lifetime, taking a toll both emotionally and physically.

There are many reports assessing the psychological damage resulting from childhood abuse, and the effects on physical health have also been well documented. For instance, this "toxic" stress has been linked to elevated cholesterol, cardiovascular disease, metabolic syndrome and other physical conditions posing a significant health risk. The research into the physical effects of abuse, however, has focused on separate, individual systems.

A new UCLA-led study for the first time examines the effects of abuse and lack of parental affection across the body's entire regulatory system, and finds a strong biological link for how negative early life experiences affect physical health. The study is published online by the Proceedings of the National Academy of Sciences.

"Our findings suggest that there may be a way to reduce the impact abuse has, at least in terms of physical health," said Judith E. Carroll, a research scientist at the Cousins Center for Psychoneuroimmunology at UCLA, and the study's lead author. "If the child has love from parental figures they may be more protected from the impact of abuse on adult biological risk for health problems than those who don't have that loving adult in their life."

The researchers studied 756 adults who had participated in a study called Coronary Artery Risk Development in Young Adults (CARDIA). They measured 18 biological markers of health risk, such as blood pressure, heart rate, stress hormone, cholesterol, waist circumference, inflammation, and blood sugar regulation, and added up their risks across these markers to create a summary index called "allostatic load." Values at the upper range across these markers indicated they were at higher biological risk for disease. Previous research has shown that higher levels of allostatic load are associated with increased likelihood of a negative health event such as a heart attack or stroke, or show declines in physical or cognitive functioning.

To determine the study subjects' childhood stress the researchers used a well-validated self-report scale called the Risky Families Questionnaire.

They found a significant link between reports of childhood abuse and multisystem health risks But those who reported higher amounts of parental warmth and affection in their childhood had lower multisystem health risks The researchers also found a significant interaction of abuse and warmth, so that individuals reporting low levels of love and affection and high levels of abuse in childhood had the highest multisystem risk in adulthood.

The researchers suggest that toxic childhood stress alters neural responses to stress, boosting the emotional and physical arousal to threat and making it more difficult for that reaction to be shut off.

"Our findings highlight the extent to which these early childhood experiences are associated with evidence of increased biological risks across nearly all of the body's major regulatory systems" said Teresa Seeman, professor of medicine in the division of geriatrics at the David Geffen School of Medicine and of epidemiology at the Fielding School of Public Health at UCLA, and the paper's senior author. "If we only look at individual biological parameters such as blood pressure or cholesterol, we would miss the fact that the early childhood experiences are related to a much broader set of biological risk indicators -- suggesting the range of health risks that may result from such adverse childhood exposures."

The authors note that the findings are based on a cross-sectional analysis and do not prove causation. It used information provided by the participants, so there may be some recall bias. Also, the analysis may not have captured other factors affecting regulatory systems, such as poor nutrition or environmental pollution.

But the findings suggest that parental warmth and affection protect one against the harmful effects of toxic childhood stress. Also, the lingering effects of childhood abuse can be linked to age-related diseases such as cardiovascular disease. Among other things, this could have an effect on long-term health care costs.

"It is our hope that this will encourage public policy support for early interventions," Carroll said. "If we intervene early in risky families and at places that provide care for children by educating and training parents, teachers, and other caregivers in how to provide a loving and nurturing environment, we may also improve the long term health trajectories of those kids."