Is Inflammation a Link Between Self-Reported Health and Infectious Disease Risk?

Self-reported health (SRH) has been consistently shown to predict morbidity and mortality. However, the mechanisms underlying this association are poorly understood. The study by Cohen and colleagues reported in this issue of Psychosomatic Medicine fills this gap by examining a potential biological mechanism: alteration of immune system functioning. The study shows that SRH predicted common cold after experimentally controlled virus inoculation in healthy individuals. More specifically, SRH predicted the cold-related illness expression as measured by objective clinical signs, whereas it did not predict the infection rates as measured by predefined increases in specific antibodies. This editorial discusses the significance of this study and the possibility that inflammation, an innate immune response, is a link between SRH and common cold risk. Because the illness expression of cold is generally attributed to increased local inflammation and SRH has been found associated with increased systemic inflammation, it is possible that SRH is a correlate of a heightened systemic inflammatory state and thus leads to increased local inflammatory responses after an exposure to a cold virus. SRH was also associated with well-known risk factors for inflammation in this study, such as overweight, perceived stress, and social isolation. Because of the strong predictive value of SRH for future morbidity and mortality and the simple low-cost tools that enable its assessment, SRH has the potential to identify high-risk individuals in various public health settings. Future research is needed to address the translational applicability of these findings and to further the mechanistic investigation in high-risk groups including older adults.