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.