Subjective age and inflammation risk in midlife adults: Findings from the Midlife in the United States (MIDUS) studies

Recent studies have suggested that subjective age—a subjective evaluation of one's own age—is a promising construct in gerontology that may contribute our understanding of risk for immune dysfunction. Nevertheless, studies documenting the association between subjective age and inflammatory biomarkers remain limited and provide mixed findings. In the present study, we revisited the relation between subjective age and systemic inflammation by utilizing a range of well-established inflammatory biomarkers (C-reactive protein, interleukin-6, fibrinogen, E-selectin, and intercellular adhesion molecule 1) through the collection of fasting blood samples before breakfast. In a large-scale dataset of midlife adults (N = 1800), we found some evidence that an older subjective age is associated with elevated inflammation when indexed by C-reactive protein and fibrinogen, as well as a composite inflammation score. However, these relations were not significant when health variables were controlled for, suggesting that the association between subjective age and systemic inflammation is fully accounted for by better health profiles among those with a younger subjective age. Additionally, the subjective age-inflammation association was influenced by slight variations in the analytic method, highlighting the importance of sensitivity analyses in this area.