We first correlated IL-6 with the five major personality dimensions, controlling for sex and age (see Table 1). Consistent with our expectations, both higher Neuroticism and lower Conscientiousness scores were related to greater circulating levels of this inflammatory marker (see Figure 1). Thus, two major personality dimensions commonly implicated in health-related behaviors and outcomes – high Neuroticism and low Conscientiousness – are also associated with high circulating IL-6, a condition associated with chronic disease and frailty. The remaining three personality dimensions were unrelated to IL-6. The correlations remained significant when we controlled for current smoking status, BMI, aspirin use in the last 2 weeks, and disease burden. Thus, although modest, the associations were remarkably stable, even when accounting for factors known to increase circulating levels of IL-6, and they are of similar magnitude to the association often reported between IL-6 and depression in large-scale studies (Penninx et al. 2003; Davidson et al. 2009, Gimeno et al. 2009).
