Self-rated health and interleukin-6: Longitudinal relationships in older adults

Abstract

Background Both self-rated health (SRH) and inflammation are implicated in chronic diseases and premature mortality. Better SRH is associated with lower proinflammatory cytokines, but there is little evidence about whether this relationship is more stable or dynamic. Objective To study the between- and within-person associations between SRH and IL-6. Methods Older adults (N = 131; Mage = 75 years) rated their health and provided blood samples for analysis of IL-6 at separate occasions every 6 months over a period up to 5 years. Age, sex, BMI, neuroticism, and statin use were examined as covariates in multilevel models. Results In bivariate models, better SRH, lower BMI, younger age, and female sex correlated with lower IL-6. In multilevel models, stable SRH (between-person differences; p < .001) but not dynamic SRH (within-person changes; p = .93) correlated with IL-6. The stable relationship persisted with demographic and health covariates in the model. Conclusions Better stable SRH but not dynamic SRH was robustly associated with lower IL-6 among older adults, lending support to previous cross-sectional findings on the relation between inflammatory markers and SRH. The findings suggest that trait-like mechanisms, rather than changes over a time scale of 6-month waves, govern this association. To further investigate the mechanisms behind the SRH–IL-6 association, studies with different measurement frequencies, higher within-person variability, and experimental approaches are warranted.

What Makes You Feel Sick After Inflammation? Predictors of Acute and Persisting Physical Sickness Symptoms Induced by Experimental Endotoxemia

“…For example, we and others have reported significant correlations between IL‐6 and specific physical and psychological sickness symptoms, such as hyperalgesia, anorexia, cognitive impairments, or negative mood and feelings of social disconnection . Recently, an inverse relationship between IL‐6 and self‐rated health has been established in a large cohort of older adults . In medical conditions, IL‐6 has been proposed as a potential driver of sickness symptoms in cancer and cancer treatment‐related side effects .…”

“…16,17,20 Recently, an inverse relationship between IL-6 and self-rated health has been established in a large cohort of older adults. 21 In medical conditions, IL-6 has been proposed as a potential driver of sickness symptoms in cancer and cancer treatment-related side effects. 6,22 Our finding that IL-6 also predicted late sickness symptoms even though plasma concentrations had normalized during this time period can be explained by neural immune-to-brain pathways that seemed to trigger immediate but also delayed effects on central processes.…”

Associations between self-rated health, sickness behaviour and inflammatory markers in primary care patients with allergic asthma: a longitudinal study

“…Also the relation between self-rated health and inflammation has mainly been investigated in cross-sectional studies. A recent longitudinal study demonstrated a stable relationship between poor self-rated health and higher IL-6 in older adults over several measurements 34 but this study did not include any measures of sickness behaviour. Because previous studies show that pro-inflammatory cytokines both causes sickness behaviour and poorer self-rated health, 35 , 36 the corresponding relationships should be investigated in allergic asthma.…”

The body remembers: Adolescent conflict struggles predict adult interleukin-6 levels

“…Chronic levels of inflammation in turn have been linked to future health difficulties ranging from metabolic syndrome to cardiovascular disease (Dandona, Aljada, Chaudhuri, Mohanty, & Garg, 2005; Libby & Theroux, 2005). More specifically, high IL-6 levels have been associated with lower self-rated health among older adults (Arnberg, Lekander, Morey, & Segerstrom, 2016), and with specific disease processes related to premature aging, including tumor formation, arthritis, and osteoporosis (Hunter & Jones, 2015).…”