U. ROCHESTER (US)—People who are engaged in life and who enjoy social interactions have lower levels of a key inflammatory molecule linked to stress—and thought to play a role in a wide range of diseases. For women, higher levels of the molecule may double the risk of death within five years.
The study by researchers at the University of Rochester suggests personality, not just race or gender, affect our ability to withstand stress-related, inflammatory diseases. The findings were published in the July issue of the journal Brain, Behavior and Immunity.
Long-term exposure to hormones released by the brains of people under stress, for instance, takes a toll on organs. Like any injury, this brings a reaction from the body’s immune system, including the release of immune chemicals that trigger inflammation in an attempt to begin the healing process. The same process goes too far as part of diseases from rheumatoid arthritis to Alzheimer’s disease to atherosclerosis, where inflammation contributes to clogged arteries, heart attacks and strokes.
The current study finds that extroverts, and in particular those with high “dispositional activity” or engagement in life, have dramatically lower levels of the inflammatory chemical interleukin 6 (IL-6). Swiss psychiatrist Carl Jung defined extroverts as focused on the world around them and most happy when active and surrounded by people. Introverts looked inward and are shy.
“Our study took the important first step of finding a strong association between one part of extroversion and a specific, stress-related, inflammatory chemical,” says Benjamin Chapman, assistant professor within the Rochester Center for Mind-Body Research and lead author of the study. “The next step is to determine if one causes the other. If we knew the direction and mechanism of causality, and it were low dispositional activity causing inflammation, we could design treatments to help high-risk patients become more engaged in life as a defense against disease.”
Some past studies had contended, and the current analysis agreed, that women and minorities have higher levels of IL-6 than white males on average. Women may be more vulnerable to stress because of hormonal differences and minorities because of factors like perceived racism, but those questions have yet to be fully answered.
While these trends exist, variations within these large groups are so great that further risk markers are needed to better determine any given patient’s actual risk. The current study looked whether particular personality traits, including low extraversion, were associated with IL-6 levels in a sample of 103 urban primary care patients aged 40 and older.
While it may difficult for patients to change their nature, part of the solution may be physical exercise as a therapy. The activity component of extraversion has been linked with exercise by past studies, as has daily physical activity with lower IL-6 levels in the aging. Still, the team is not convinced that exercise represents the whole answer.
“Beyond physical activity, some people seem to have this innate energy separate from exercise that makes them intrinsically involved in life,” Chapman says. “It will be fascinating to investigate how we can increase this disposition toward engagement. Potentially, you might apply techniques developed to treat depression like ‘pleasurable event scheduling’ to patients with low dispositional energy, where you get people more involved in life by filling their time with things they enjoy as a therapy.”
The work was supported by the General Clinical Research Center at the University of Rochester Medical Center and by the National Center for Research Resources, part of the National Institutes of Health.
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