Women who have had harder lives are more likely to get breast cancer, an Israeli researcher said.

Ronit Peled of Ben-Gurion University of the Negev interviewed 622 women from 25 to 45 years old, 255 of whom had had breast cancer. They were asked about happiness, optimism, anxiety and negative life events.

"The results showed a clear link between outlook and risk of breast cancer, with optimists 25 percent less likely to have developed the disease. Conversely, women who suffered two or more traumatic events had a 62 percent greater risk," Peled said. "Young women who have been exposed to a number of negative life events should be considered an 'at-risk' group for breast cancer and should be treated accordingly."

A news release on the research pointed out that the women may have had more negative views since they had already been diagnosed with breast cancer.

"The mechanism in which the central nervous, hormonal and immune systems interact and how behavior and external events modulate these three systems is not fully understood," Peled said. "The relationship between happiness and health should be examined in future studies and relevant preventative initiatives should be developed."

The work appeared in the August 2008 edition of the British journal BMC Cancer.