The answer is an emphatic no, according to Swedish and Danish researchers who conducted a study that was recently published online by the journal CANCER.

The idea that some people might have an increased risk of cancer – perhaps those who are extroverted, emotionally contained, or who have aggressive, Type A personalities has been an insidious, blame-the-victim kind of notion for decades. And some studies have suggested a link between personality traits and cancer.

But the huge, new study of nearly 30,000 Swedish twins who were followed for 25 years appears to settle the issue once and for all. The researchers studied two personality traits in particular, extroversion (a high tolerance for intense social activity) and neuroticism (high anxiety and high emotional arousal), and concluded that there is no link between these traits and cancer. “For now, we can conclude that our results add to the evidence that personality does not contribute to the development of cancer,” they wrote.

Debunking the personality-cancer hypothesis is important, said Ann Webster, a psychologist at the Mind/Body Medical Institute in Boston.

“Thank heavens someone has finally discovered this,” she said. “I never believed that hypothesis.”

“I am more interested in looking at people’s optimism, resilience, coping styles and willingness to make lifestyle changes.”

The connection between cancer and personality has been debunked, but behavior is still important, said Dr. LaMar McGinnis, a senior medical consultant for the American Cancer Society in Atlanta. He noted that smoking, excessive drinking, lack of exercise and obesity all contribute to cancer.