By Margarita Nahapetyan
Physical abuse during childhood is associated with a high chance of developing cancer later in life, according to the experts at the University of Toronto, Canada.
In their study. Canadian researchers came to the conclusion that childhood physical abuse is associated with a 49 per cent increased risk of cancer in adulthood. Even after taking into consideration major health risk factors, such as childhood stressors, adult socioeconomic status and adult behaviors including smoking, drinking and lack of physical activity, the relationship between childhood physical abuse and cancer remained significant, the authors wrote.
The findings were based on data from the 2005 Canadian Community Health Survey, focusing on the provinces of Manitoba and Saskatchewan. Of the 13,092 respondents who took part in the study, 7.4 per cent reported that they had been physically abused as a child by someone close to them, and 5.7 per cent said that they had been later diagnosed with cancer by a health professional. Childhood physical abuse was linked to 49 per cent higher chances of the disease. The odds ratio reduced only slightly to 47 per cent higher odds when the numbers were adjusted to account for unhealthy adult behaviors, socioeconomic status, and other stressors during childhood, such as divorce.
The lead author of the study, researcher Esme Fuller-Thomson of University of Toronto's Factor-Inwentash Faculty of Social Work and Department of Family and Community Medicine, said that she was rather shocked by her own findings. "I was totally surprised that that relationship was so strong," she said in an interview. "So there is something going on, but right now it is a black box. It is a question mark right now."
Fuller-Thomson says there are many possible reasons why physical abuse might be a factor of cancer risk, though all these reasons at this point are just theories. One theory is that chronic stress that an abused child is constantly under, brings up levels of the "fight or flight" hormone, cortisol. Increased levels of the hormone might interfere with the immune system's ability to detect and get rid of cancer cells. "With every stressor, you respond with a huge amount of this hormone which sends your heart beat up and can cause suppression of your immune system," Fuller-Thomson explained. "And so that is one potential hypothesis."
Sarah Brennenstuhl, a doctoral student at the U of T and a co-author of the study, said that social scientists are less likely to study and analyze what goes under the skin, while medical scientists have started to investigate issues like poverty and education as explanations behind ailments. The interaction between who you are, your position in society and what is going on physiologically, "I think we need to look at those more closely," Brennenstuhl said.
However, the researchers emphasized that individuals who were the victims of physical abuse in childhood should not think now that they are going to necessarily develop cancer. Fuller-Thomson stressed out that the findings need to be supported by other larger studies before the scientists could say for sure that child abuse is a risk factor for cancer. She said that more research is needed in order to explain the higher cancer rates that were found in this study, and to better understand what mechanisms might stand behind.
The study was published in July 15 issue of the journal Cancer.