Negative, hostile personality types were significantly associated with increased risk for type 2 diabetes in older women, a large observational study found.
Among nearly 140,000 postmenopausal women without diabetes at baseline and followed for 14 years, those in the highest quartile of optimism as determined by questionnaires were 12% less likely to develop diabetes compared with those in the lowest quartile (HR 0.88, 95% CI 0.84-0.92), reported a research team led by Juhua Luo, PhD, of Indiana University in Bloomington.
Compared with women in the lowest quartiles, those in the highest quartile for hostility were 17% more likely to get diabetes (HR 1.17, 95% CI 1.12-1.23) and those in the highest quartile for negative emotional expressiveness were 9% more likely (HR 1.09, 95% CI 1.05-1.14), Luo’s group said online in Menopause, the journal of the North American Menopause Society (NAMS).
The risk was independent of demographic characteristics, depressive symptoms, and health behaviors tied to personality traits that could affect diabetes risk, such as poor diet, physical inactivity, alcohol use, and smoking, the researchers said.
“Accumulating evidence demonstrates that depression is also associated with increased risk of diabetes. However, in addition to depression, little is known about whether other psychological factors, including personality traits, are associated with diabetes risk,” Luo and colleagues said.
However, the idea that personality might influence health has attracted a lot of attention, they said. “Our findings are consistent with previous studies reporting that positive psychological well-being was associated with lower risk of incident coronary heart disease and longevity. Several studies have also reported that positive psychological traits, including optimism, were associated with better glucose control and lower mortality rates in patients with type 2 diabetes.”
The study results could be used to tailor treatment and prevention strategies to personality types, NAMS executive director JoAnn Pinkerton, MD, told MedPage Today in an email. “For women with negative personality traits and early diabetes, the approach could include early testing and having a nutritionist work with the patient more intensively to get control of the blood sugar early in life,” she said. “At the same time, an educator or counselor could work with the woman to identify strategies to overcome negative thinking and cynicism. Early intervention could decrease long-term health risks.”
Defeating negative thinking is challenging but possible, Pinkerton said. “Although personality may be genetically based and hard to change, women can learn to overcome some of the negativity and cynicism. Improved coping skills make women more likely to improve their blood sugars which will improve their moods and quality of life.” Such skills include mindfulness training and learning to identify negative thought patterns, she said.
Luo’s group analyzed data on 139,924 postmenopausal women ages 50-79 enrolled in the Women’s Health Initiative, a large prospective cohort study. All participants were healthy and diabetes-free at baseline. Personality traits were determined by questionnaires. Optimism was assessed with the Life Orientation Test, and negative emotional expressiveness was assessed with four items from the Emotional Expressiveness Questionnaire, for example.
During a mean 14 years of follow-up, 19,240 participants reported incident type 2 diabetes. Associations were adjusted for common demographic factors, health behaviors, and depressive symptoms.
Mechanisms that may link personality with diabetes risk apart from health behaviors remain uncertain, but Luo’s group suggested some possibilities. “Psychosocial factors may influence the development of diabetes directly through mechanisms such as glucose dysregulation and inflammation. Our data suggest that additional biological mechanisms related to cortisol regulation, or reduced inflammation, may be more likely to reside on the pathway between personality characteristics and diabetes.”
In addition, “[t]here is some evidence showing that a rise in the concentration of proinflammatory cytokines and glucocorticoids, particularly cortisol, is present in conditions of chronic stress and often in depression, which may lead to accumulation of visceral fat or lipolysis or release of free fatty acids and then insulin resistance,” the study authors said.
The study only included postmenopausal women in the U.S. who were healthy at baseline, so the results might not apply to other populations, Luo and colleagues said. Another limitation of the study was that it only assessed personality traits at baseline and didn’t take into account potential personality changes over time, they said.
“People may benefit from knowing how their own personality traits might heighten risk for diabetes, and potentially take protective actions to reduce risk,” the researchers said. “It may also be of benefit in future research to investigate whether diabetes prevention intervention may be tailored according to different personality traits.”
The study was funded by the National Institutes of Health and the U.S. Department of Health and Human Services.
No study authors reported conflicts of interest.