Being subjected to abuse during childhood entails a markedly increased risk of developing obesity as an adult. This is the conclusion of a meta-analysis carried out on previous studies, which included a total of 112,000 participants. The analysis was conducted by researchers at Karolinska Institutet in Sweden, and has been published in the journal Obesity Reviews.
“The study clearly shows that difficult life events leave traces which can manifest as disease much later in life. The mechanisms behind this process include stress, negative patterns of thought and emotions, poor mental health, increased inflammation, as well as lowered immune function and metabolism,” says Erik Hemmingsson, researcher at the Huddinge Department of Medicine at Karolinska Institutet, who is also linked to the Karolinska University Hospital’s Obesity Centre in Huddinge, Stockholm County.
Based on a meta-analysis, in which 23 studies with a total of 112,000 participants, he and his colleagues calculated that the risk of obesity was 34 percent higher among adults who had been subjected to abuse as children than among non-abused adults. When categorised based on different forms of abuse, the study showed that physical abuse during childhood increased the risk of obesity by 28 percent, emotional abuse by 36 percent, sexual abuse by 31 percent, and general abuse by 45 percent. Among those who had been subjected to severe abuse, the risk increased by 50 percent, compared to 13 per cent for moderate abuse.
“These findings indicate causality, where the abuse is the cause of the obesity later in life. However, not everyone who is subjected to abuse will develop obesity, and not all obese individuals have been abused, so there are obviously other causes too. At the same time, it is important to remember that child abuse is more common than we think, and it needs to be brought to light. Between five and ten per cent of the adult population say that they have been subjected to some form of abuse during childhood,” says Erik Hemmingsson.
In another recently published paper, Erik Hemmingsson has developed a new theoretical model for how stressful childhood experiences increase the risk of obesity, via psychological and emotional factors. These factors impact negatively on appetite regulation, metabolism, eating behaviour, sleep, inflammation and cognitive function - which in turn pave the way for obesity. Erik Hemmingsson hopes that the published studies might help disprove the many preconceptions that exist about people who are overweight, as they show that obesity is caused by so many other factors than overeating or a sedentary lifestyle.
“Our current view of both the occurrence and treatment of obesity is far too narrow, since we talk almost exclusively about diet and exercise,” he explains. “These new studies indicate that we need to take a much more holistic approach in the treatment and prevention of obesity, where we give more consideration to the individual’s childhood as well as psychological and emotional aspects. It can for example be about self-esteem and self-image, thought patterns, emotional stress factors and mental ill-health, and there may thus be a need for psychotherapy or cognitive therapy to obtain lasting positive effects on obesity.”
How Childhood Trauma Can Cause Adult Obesity
Dr. Vincent Felitti, founder of Kaiser Permanente’s Department of Preventive Medicine and director of its obesity-treatment program, was seeing some good results. His patients were losing 50, 80, even hundreds of pounds. He might have considered the program a success, if not for the fact that the participants who were doing the best - those who were both the most obese and losing the most weight - kept dropping out.
Felitti was baffled. Why, invariably, did so many patients quit just as they approached their healthy goal weight? Ella, for instance, a middle-aged woman who entered the program in the mid-1980s morbidly obese at 295 lb., had managed to whittle her frame by 150 lb. over six months. “Instead of being happy, she was having anxiety attacks and was terrified,” Felitti says.
He asked Ella what she thought was going on. “Finally, the story comes out,” he says. “She had been molested as a child, both within her family and outside it. She tried to escape by marrying at 15, at her mother’s urging. It was a disastrous marriage - her husband was crazy jealous. They divorced in two years. She remarried. Her new husband was also jealous. He was convinced that when she was out hanging the laundry, she was sexually posturing to attract the neighbors.”
When Ella was overweight, Felitti learned, her husband was less suspicious. And her fear of his rage - perhaps he saw her new slimmer weight as a provocation? - was probably spurring her anxiety.
Felitti wondered if there was something similar barring weight loss in other patients - or causing obesity itself. In the late ‘80s, he began a systematic study of 286 obese people, and discovered that 50% had been sexually abused as children. That rate is more than 50% higher than the rate normally reported by women, and more than triple the average rate in men. Indeed, the average rates of sexual abuse are themselves unsettling: according to a large 2003 study conducted by John Briere and Diana Elliott of the University of Southern California, 14% of men and 32% of women said they were molested at least once as children.
In recent years, studies by both Felitti and others have largely confirmed the association between sexual abuse - as well as other types of traumatic childhood experience - and eating disorders or obesity. A 2007 study of more than 11,000 California women found that those who had been abused as children were 27% more likely to be obese as adults, compared with those who had not, after adjusting for other factors. A 2009 study of more than 15,000 adolescents found that sexual abuse in childhood raised the risk of obesity 66% in males in adulthood. That study found no such effect in women, but did find a higher risk of eating disorders in sexually abused girls.
Discoveries by Felitti and colleagues have also helped give rise to broader work linking stressful experiences early in life - as early as in the womb - to effects on health and behavior later on, such as an increased risk of heart disease or becoming addicted to drugs. Scientists are finding that such effects are not only long-lasting, but can even be inherited by future generations.
The meta-analysis has been partially funded through Stockholm County Council.
’ Effects of childhood abuse on adult obesity: a systematic review and meta-analysis ‘, Erik Hemmingsson, Kari Johansson, and Signy Reynisdottir. Obesity Reviews, online first 14 August 2014, doi: 10.1111/obr.12216 .
’ A new model of the role of psychological and emotional distress in promoting obesity: conceptual review with implications for treatment and prevention ‘, Erik Hemmingsson, Obesity Reviews 2014 Sep;15(9):769-79, online first 16 June 2014, doi: 10.1111/obr.12197 .
While it’s common knowledge that childhood trauma can have far-reaching and sometimes dire consequences for adult mental health, it’s less obvious that abuse, neglect, parental alcoholism, severely dysfunctional family patterns, and other stresses in childhood can severely affect adult physical health, and even mortality. However, a path-breaking epidemiological survey called the Adverse Childhood Experiences (ACE) Study, initiated jointly by the Kaiser Permanente HMO in California and the Centers for Disease Control and Prevention in 1995- 1997 and still continuing, demonstrates an astonishing correlation between childhood maltreatment and later-life medical illnesses and premature death.
The ACE study was based on detailed interviews with more than 17,000 Kaiser Permanente members about their childhood experiences of neglect, abuse, and family dysfunction. As the health profiles of these participants have been tracked through the years, about 70 scientific articles have been published linking childhood adversity to a host of mental and medical conditions, including among the latter autoimmune, heart, lung, and liver diseases, cancer, hepatitis or jaundice, diabetes, bone fractures, and sexually transmitted diseases.
The study came about almost by accident: it was the entirely unexpected consequence of a Kaiser Permanente weight-loss program that went strangely awry. During the mid-1980s, Vincent Felitti, founder of Kaiser Permanente’s Department of Preventive Medicine, began directing a new obesity-treatment program, based on the technique of “absolute fasting” - no solid foods, only liquids supplemented by 420 calories daily derived from vitamins, essential amino and fatty acids, and electrolytes. At first, the program seemed to be a smashing success. People lost 50 pounds and up. The weight loss for some of these patients, many of whom were morbidly obese, was a staggering 300 pounds, which even exceeded what’s ordinarily accomplished with bariatric surgery.
For further information about this research, please contact:
Erik Hemmingsson, PhD
Tel: +46 (0)8-672 43 13 or +46 (0)736-33 43 98
Contact the Press Office at Karolinska Institutet
Karolinska Institutet is one of the world’s leading medical universities. It accounts for over 40 per cent of the medical academic research conducted in Sweden and offers the country’s broadest range of education in medicine and health sciences. Since 1901 the Nobel Assembly at Karolinska Institutet has selected the Nobel laureates in Physiology or Medicine.