One in six Californians has experienced significant trauma in childhood – and enough stress to put their long-term health at risk, according to a study released yesterday.

The study, “A Hidden Crisis: Findings on Adverse Childhood Experiences in California,” was issued by the Center for Youth Wellness in partnership with the non-profit Public Health Institute. Pediatrician Nadine Burke Harris founded the Center for Youth Wellness in San Francisco’s Bayview-Hunter’s Point neighborhood in 2007. She is well known nationally for her efforts to make screening for adverse experiences a routine part of health care.

Adverse childhood experiences have been measured since 2008 as part of a larger health survey of Californians conducted by the California Department of Public Health. “A Hidden Crisis” is drawn from the first of those results to be released. The survey asked about 12 specific experiences that fall under one of three headings: abuse, neglect, or family dysfunction. They include, for instance, parental divorce, witnessing domestic abuse in the home or experiencing emotional, sexual or physical violence.

Four adverse experiences in childhood are the tipping point for later health problems, including double the likelihood of coronary heart disease and cancer and almost two and a half times the risk of stroke compared to people with one adverse experience. Sixteen percent of Californians in the representative survey had four or more adverse events.

Burke Harris has seen firsthand the breadth of adverse experiences in her work from low-income neighborhoods, she explained yesterday at the Children Can Thrive conference in San Francisco. The conference coincided with the release of “Hidden Crisis.”

Burke Harris began screening children for adverse experiences when she was treating young people at a clinic in Bayview-Hunters Point, an impoverished area in San Francisco that sees most of the city’s homicides. Her patients, she said, “experienced shootings in their neighborhood, neighbors who broke into their houses and stole their things, watched family members being arrested right in front of them.”

Such emotional trauma often translates into poor health choices, like higher rates of drinking and smoking. Yet, Burke Harris noted, those behaviors don’t fully explain poor health. “A person who has an adverse childhood experience score of 7 or more, their risk of ischemic heart disease is 350 percent [higher than average]. That’s more than if you are a smoker, that’s more than if you have high cholesterol, that’s more than if you have high blood pressure.”

Researchers believe that toxic stress is the link between trauma and poor health. Stress activates the body’s flight or fight response, a normal reaction to fear. Toxic stress results from ongoing exposure to trauma, where the body’s stress reaction is activated over and over again. The resulting wear and tear on the body may explain the gap between health and health behaviors, like the heart disease risk Burke Harris described.

Adverse experiences affect a wide swath of Californians. The pioneer study of these childhood traumas, conducted by Vincent Felitti and Robert Anda and published in 1998, surveyed 17,000 largely white and college educated patients of Kaiser Permanente in San Diego. They found that more than 12 percent had four or more adverse experiences in childhood. “No one had asked these questions before,” Felitti said at the conference.

“If we are only looking in our brown and black population,” Burke Harris said, “we are missing a lot of people.”

Still, people with less money and education are more likely to have the kinds of childhood experiences that are harmful to health later in life. About 20 percent of people who live below the poverty line have four or more adverse experiences, for instance, compared to 13 percent of wealthier people.

California is the first state to release data on adverse childhood experiences and was also the first to start collecting this information. Twenty-three other states have since followed suit.

The California data suggests that millions in the state may see their health and longevity diminished by early life trauma. But Harris Burke and Felitti both said that research on adverse experiences points to a hopeful new direction for improving health.

Simply asking patients in the survey about their traumatic childhood experiences was followed by a 35 percent reduction in their visits to the ER and doctor’s office, according to Felitti. “Listening was a radical form of healing,” he said.

Burke Harris doesn’t expect that doctors can prevent childhood trauma, but she does think treatment can improve long-term health – and that’s why screening for adverse experiences is crucial. “The hope is prevention,” she said. “The first step in prevention is awareness.”