THURSDAY, Oct. 19, 2006 (HealthDay News) -- A new study in rats suggests a link between personality and cancer susceptibility.
Researchers at the University of Chicago say timid rats were more likely to develop cancer and to die sooner than more "adventuresome" rats. The findings suggest the need to examine the links between behavior traits and cancer in humans, the team said.
For this study, the Chicago group used a breed of rats prone to breast and pituitary tumors. Female rats that appeared apprehensive of new experiences as infants remained that way as they grew older. They also died earlier of breast and pituitary tumors than their braver sisters.
The more timid rats were also more likely to have irregular reproductive cycles than the tougher rats -- 52 percent vs. 22 percent. This disruption may account for hormonal differences associated with the development of cancer at an earlier age, the researchers speculated.
By the time they were 390 days old (middle age for rats), 80 percent of the timid rats had developed mammary cancer, compared with 38 percent of the bolder rats. The timid rats had an average life span of 573 days, compared to 850 for the more adventuresome rodents.
There was no difference between the two groups in the length of time between the onset of cancer and death.
The study was published in the current issue of Hormones and Behavior.
The findings suggest that more research is needed into temperament and cancer risk in humans, the study authors said. Most current research into cancer and personality focuses on survival once a person has already been diagnosed with cancer.
"Human studies may need to consider more basic behavior traits than those already considered," researcher Martha McClintock, a professor of psychology, said in a prepared statement.
The U.S. National Cancer Institute has more about cancer.