Association between serum interleukin-6 concentrations and mortality in older adults: the Rancho Bernardo study

PLoS One. 2012;7(4):e34218. doi: 10.1371/journal.pone.0034218. Epub 2012 Apr 13.

Abstract

Background: Interleukin-6 (IL-6) may have a protective role in acute liver disease but a detrimental effect in chronic liver disease. It is unknown whether IL-6 is associated with risk of liver-related mortality in humans.

Aims: To determine if IL-6 is associated with an increased risk of all-cause, cardiovascular disease (CVD), cancer, and liver-related mortality.

Methods: A prospective cohort study included 1843 participants who attended a research visit in 1984-87. Multiple covariates were ascertained including serum IL-6. Multivariable-adjusted Cox proportional hazards regression analyses were used to examine the association between serum IL-6 as a continuous (log transformed) variable with all-cause, CVD, cancer, and liver-related mortality. Patients with prevalent CVD, cancer and liver disease were excluded for cause-specific mortality.

Results: The mean (± standard deviation) age and body-mass-index (BMI) of participants was 68 (± 10.6) years and 25 (± 3.7) Kg/m(2), respectively. During the 25,802 person-years of follow-up, the cumulative all-cause, CVD, cancer, and liver-related mortality were 53.1% (N = 978), 25.5%, 11.3%, and 1.3%, respectively. The median (± IQR) length of follow-up was 15.3 ± 10.6 years. In multivariable analyses, adjusted for age, sex, alcohol, BMI, diabetes, hypertension, total cholesterol, HDL, and smoking, one-SD increment in log-transformed serum IL-6 was associated with increased risk of all-cause, CVD, cancer, and liver-related mortality, with hazard ratios of 1.48 (95% CI, 1.33-1.64), 1.38 (95% CI, 1.16-1.65), 1.35 (95% CI, 1.02-1.79), and 1.88 (95% CI, 0.97-3.67), respectively. CRP adjustment attenuated the effects but the association between IL-6 and all-cause and CVD mortality remained statistically significant, independent of CRP levels.

Conclusions: In community-dwelling older adults, serum IL-6 is associated with all-cause, CVD, cancer, and liver-related mortality.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Aged
  • Cardiovascular Diseases / blood
  • Cardiovascular Diseases / mortality
  • Female
  • Humans
  • Interleukin-6 / blood*
  • Liver Diseases / blood
  • Liver Diseases / mortality
  • Male
  • Middle Aged
  • Neoplasms / blood
  • Neoplasms / mortality
  • Proportional Hazards Models
  • Prospective Studies

Substances

  • Interleukin-6