Poorer self-rated health is associated with elevated inflammatory markers among older adults

Abstract

Objective Self-rated health is a strong independent predictor of mortality after accounting for objective health status, behavioral risk factors, and sociodemographic characteristics. However, mechanisms underlying this association are largely unexplained. Inflammation has been associated with increased risk of morbidity and mortality in the elderly. The current study aimed to: 1) examine associations between self-rated health and serum inflammatory markers in older adults; 2) examine the relative strength of these associations for self-rated health versus self-rated change in recent health; 3) examine components of self-rated health that may underlie the association between inflammation and global self-rated health. Methods Self-rated health, as measured by the RAND health survey, and serum interleukin (IL)-6 and C-reactive protein (CRP) were assessed among 250 generally healthy older adults (185 women, 65 men; average age= 63.8 ± 13.7 years). Results A series of linear regression analyses demonstrated that poorer self-rated health was significantly associated with higher IL-6 and CRP. These relationships remained after controlling for age, body mass index, gender, and objective health conditions. These associations also remained after controlling for depressive symptoms, neuroticism, perceived change in health over the past year, and health behaviors (smoking, sleep quality, and physical activity). Analyses of RAND component measures demonstrated that poorer physical functioning was significantly associated with IL-6; the relationship between global self-rated health and both IL-6 and CRP remained after accounting for perceived physical functioning. Conclusions Poorer self-rated health is associated with elevated serum inflammatory markers among generally healthy older adults. The relationship of self-rated health with inflammatory markers is not secondary to depressive symptoms, neuroticism, or recent changes in perceived health. Subjective ratings of health provide important clinical information regarding inflammatory status, beyond traditional objective risk factors, even among generally healthy individuals.

Significance of serum immune markers in identification of global functional impairment in the oldest old: cross-sectional results from the BELFRAIL study

“…Our results are in line with Christian et al (2011), who reported similar results with the only significant self-rated health component, physical functioning. Moreover, a recent review by Singh and Newman (2011), based on the results from major epidemiologic studies, showed IL-6 to be robustly associated with physical functioning in older adults.…”

“…However, this study is the first to show the additional significance of IL-6 as a global functioning marker in the oldest old. Only a few studies have reported that poorer global self-rated health is associated with elevated inflammatory markers among older adults (Christian et al 2011;Cohen et al 1997). Christian et al (2011) reported IL-6 and CRP to be associated with self-rated health in a relatively healthy study population with caregiving responsibilities with a mean age of 63.8 years, which is in line with our results in the community-dwelling oldest old, even with high comorbidity.…”

“…Although impairment in one individual aspect of functioning might have different degrees of effect on the global functioning of older people, only a few studies have reported that poorer self-rated global health is associated with elevated inflammatory markers among older adults (Christian et al 2011;Cohen et al 1997). To our knowledge, no associations for global functioning with serum inflammatory markers have been described.…”

Interleukin-6 predicts short-term global functional decline in the oldest old: results from the BELFRAIL study

“…Nevertheless, IL-6 could simply be an indicator of biological frailty or immunosenescence in general, in which IL-6 is likely to represent a general down-spiral pathway involving multiple pathophysiological mechanisms and therefore reflects the associated patient's global function (Penninx et al 2004). Only two previous studies have reported that poorer self-rated global health is associated with elevated IL-6 levels in older adults (Christian et al 2011;Cohen et al 1997). We showed a clear dose-response relationship of global functional decline with increasing serum levels of baseline IL-6.…”

“…Only poor self-rated global health has been previously associated with elevated inflammatory markers in older persons (Christian et al 2011;Cohen et al 1997). Different sets of inflammatory markers have been measured in studies with diverse assays and in various settings, disabling inflammatory marker comparability between various studies.…”