Personality traits and inflammation in men and women in their early 70s: the Lothian Birth Cohort 1936 study of healthy aging.

OBJECTIVES: Studies have reported associations between the five-factor model's personality traits and inflammation markers interleukin-6 (IL-6) and C-reactive protein (CRP). Findings, however, have been inconsistent. This study investigates these associations in individuals who ranged in age from approximately 70 to 73 years.
METHODS: Participants were from the Lothian Birth Cohort 1936 (n = 818). Acute-phase proteins-CRP and fibrinogen-were measured at ages approximately 70 years (first wave) and 73 years (second wave), and the inflammatory cytokine IL-6 was measured at age 73 years. Personality traits were measured at age 70 years using two instruments, the International Personality Item Pool and the NEO Five-Factor Inventory.
RESULTS: Lower International Personality Item Pool conscientiousness was cross-sectionally associated with elevated CRP, such that 1 standard deviation higher conscientiousness was associated with 22% lower odds of having a CRP level greater than 3 mg/l (odds ratio = 0.78; 95% confidence interval = 0.67-0.91). NEO Five-Factor Inventory openness was negatively associated with CRP (odds ratio = 0.79; 95% confidence interval = 0.67-0.94) and IL-6 (β = -.08, p = .045) at age 73 years; these associations were attenuated by 26% and 63%, respectively, after adjusting for social background and prior cognitive ability. Body mass index mediated some (14%-18%) of the conscientiousness-inflammation association, whereas common health behaviors such as smoking, alcohol consumption, and physical activity did not significantly mediate the personality trait-inflammatory marker association.
CONCLUSIONS: The findings add some support to accumulating evidence for low conscientiousness being linked to higher levels of inflammation and poorer general health.