Abstract 1136: Association of C-reactive Protein (CRP) and Interleukin-6 (IL-6) With Longevity Into the 80s and 90s: The Rancho Bernardo Study
Background: As the average age of the U. S. population increases, interest has grown in factors associated with exceptional longevity. High levels of inflammatory markers such as CRP and IL-6 are associated with obesity, insulin resistance, and cardiovascular disease. However, it is unknown whether these markers play a role in determining lifespan and, if so, what the potential reduction in lifespan may be.
Objective: To determine the sex-specific associations of CRP and IL-6 levels with survival time and lifespan among older community-dwelling participants in the Rancho Bernardo Study.
Methods: 610 men and 743 women with a mean age of 73 years who had available serum CRP and IL-6 measurements at baseline (1984 – 87) were followed for mortality through 2008. Those with CRP > 15mg/L were excluded. Participants must have been old enough at baseline to be capable of achieving age 80 during follow-up. Accelerated failure time models were employed to determine the association of CRP and IL-6 with survival. Linear regression was used to determine associations with lifespan among those who died.
Results: During follow-up, 935/1353 (69%) participants died. Average age at death was 84.7 yrs for men and 86.5 yrs for women. Among men, in models adjusted for age, BMI, waist, physical activity, alcohol use, smoking, blood pressure, comorbidities and lipids, each standard deviation (SD) increase in CRP was associated with 15% decrease in survival time (p<0.0001), and among those who died, a 1.1 year decrease in lifespan (p<0.0001). Each SD increase in IL-6 in men was also associated with a 15% decrease in survival time (p<0.0001), and a 0.91 year decrease in lifespan (p<0.0001). In the same adjusted models in women, CRP was not associated with survival time or lifespan before or after additional adjustment for current estrogen use. Each SD increase in IL-6 in women was associated with an 8% decrease in survival time (p=0.0002) and a 1.1 year shorter lifespan (p=0.0005). Addition of CRP and IL-6 to the same fully adjusted models did not alter results for either sex.
Conclusions: IL-6 is associated with both survival time and lifespan among persons living into the 80s and 90s. CRP was significantly associated for both outcomes in men but not women, despite adjustment for known confounders.