Sense of purpose in life and inflammation in healthy older adults: A longitudinal study

Background: A higher sense of purpose in life has been linked with reduced risk of age-related chronic health conditions that share elevated inflammation as a key risk factor (e.g., neurodegenerative diseases, heart disease, and diabetes). While prior research has documented cross-sectional associations between higher sense of purpose and lower inflammation, few studies have examined the association between purpose and changes in inflammation over time. Objective: We tested if a higher sense of purpose was prospectively associated with lower likelihood of developing unhealthy C-reactive protein levels in older adults who initially had healthy CRP levels (i.e., <3 ug/mL). Methods: Participants were 6925 adults aged > 50 in the Health and Retirement Study who were followed for 8 years. Participants completed the purpose in life subscale of the Ryff Psychological Well-being Scales at study baseline in 2006/2008. CRP was obtained from blood spots collected at baseline and after 4 and 8 years of follow-up. Pooled logistic regression estimated discrete-time hazard ratios (HR) and 95% confidence intervals (CI) for the association between baseline purpose and onset of unhealthy CRP levels (>3 ug/mL). Results: There was no strong evidence of an association between baseline continuous purpose scores and onset of unhealthy CRP levels over time in the overall analytic sample. In sex-stratified models, higher purpose was associated with lower hazards of developing unhealthy CRP levels among men, while associations were null in women (e.g., in sociodemographics-adjusted model, men: HR=0.89, 95% CI: 0.79-0.99; women: HR=0.96, 95% CI: 0.85-1.08; interaction between continuous purpose scores and sex p = 0.15). Conclusions: Findings suggest that a higher versus lower sense of purpose is associated with lower inflammation levels in older men. In specific populations, purpose may serve as a novel target for future interventions aimed at reducing inflammation