Personality Doesn't Affect Cancer Risk
No Link Seen in Large, Long-Term European Study
Jan. 24, 2005 -- Personality traits don't increase cancer risk, say Danish
researchers in the March 1 edition of the journal Cancer.
Pernille Envold Hansen, MA, and colleagues studied nearly 30,000 Swedish
twins, following them for 25 years. The twins had enrolled in the Swedish Twin
Registry when they were 15-48 years old.
Back in 1973, the twins had taken an 18-item personality questionnaire. The
survey gauged neuroticism and extroversion, two traits that have drawn
speculation about cancer risk.
The researchers also accessed the Swedish Cancer Registry, which covers the
entire Swedish population. In Sweden, pathologists are required to report
tumors, and virtually all cancers (98%) are verified.
During the study, the twins had a total of 1,898 cancers.
Personality Not a Factor
The data showed no connection between the development of cancer and
neuroticism or extroversion.
Neuroticism is associated with emotional arousal. Highly neurotic people
tend to be more worried, anxious, and emotionally unstable than others.
But neuroticism apparently has nothing to do with cancer, the researchers
say. They found no evidence linking low neuroticism to any type of cancer.
No Extra Cancer Risk for Extroverts
The study also found no ties between cancer and another personality trait --
"Extroverts tend to have a nervous system that quickly inhibits excess
stimulation," the researchers explain. That makes intense social activity
tolerable -- and sometimes even desirable -- for extroverts.
Extroverts were not more likely to get cancer, say the researchers.
What's more, extroversion and neuroticism weren't associated with behaviors
that increase cancer risk. For instance, extroverts and people with low
neuroticism weren't especially likely to smoke.
The researchers took into account alcohol intake, exercise, diet, body mass
index (BMI), oral contraceptives, and education. Personality didn't sway any of
those factors toward cancer risk.
Other studies have suggested that personality affects cancer risk. But some
of that work is flawed, say the researchers. They note that
"well-conducted" studies on cancer and other personality traits are in
line with their findings.
For instance, the researchers note that a 20-year study of more than 11,000
women showed no link between type A behavior and breast cancer. Type A behavior
was defined as time urgency, ambitiousness, competitive drive, and
Likewise, other studies have shown that hostility and psychological
vulnerability don't affect cancer risk, say the researchers.
It's possible that personality and high life stress could interact to
influence cancer risk, they say. But so far, that hasn't been verified.