The role of inflammation in the relationship of self-rated health with mortality and implications for public health: Data from the English Longitudinal Study of Aging (ELSA)

Self-rated health (SRH) predicts mortality after adjustment for potential confounders, including measures of health status. Prodromal disease might lead to worsened SRH and higher mortality. But no study of SRH and mortality has focussed on inflammation. The objective of this study is to investigate the influence of inflammation upon the association between SRH and mortality in a British cohort. The English Longitudinal Study of Ageing (ELSA) involves interviewing participants aged over 50 every two years. We analysed data for 3405 men and 4139 women. Mortality for consenting members was detected by linkage with UK National Health Care registry up to March 2012. Demographic, clinical, and health behaviours at wave 2 were treated as confounders, as well as inflammation-related disease and C-reactive protein (CRP). A five-step hierarchical multivariable logistic regression was estimated. An association was observed between SRH and mortality after adjusting for all variables. In men, compared to those with excellent health, CRP only, and CRP and inflammation-related disease combined, could explain 7.03% and 24.35% of increased risk of dying associated with poor health, respectively. For women, the corresponding figures were 8.95% and 24.28%, respectively. Inflammation is associated with increased risk of death, and may help to explain approximately a quarter of the association between SRH and mortality. Individuals with relatively poor SRH may be aware of underlying inflammation that increases the risk of illness and death, and this may lead to increased use of services, for example. Identifying the cause and treating inflammation in those without a diagnosis may help to increase survival and life quality among those who perceive their health to be relatively poor.