The IL-6 -174G>C polymorphism is associated with cardiovascular diseases and mortality in 80-year-old humans

Area of Science:

• Genetics and Cardiovascular Disease Epidemiology
• Molecular Biology and Aging Research

Background:

• Chronic low-grade interleukin-6 (IL-6) elevations indicate subclinical cardiovascular disease (CVD) and predict mortality in the elderly.
• The IL-6 -174G>C promoter polymorphism is investigated for its association with CVD and mortality risk.

Purpose of the Study:

• To test if the IL-6 -174G>C polymorphism is linked to CVD prevalence and mortality in 80-year-olds.
• To determine if this polymorphism independently predicts mortality in a longitudinal elderly cohort.

Main Methods:

• Longitudinal study of 324 healthy 80-year-olds, with 18% having a history of CVD.
• Analysis of IL-6 -174G>C polymorphism, serum IL-6 levels, CVD prevalence, and all-cause mortality over six years.
• Cox regression models used to assess mortality risk, considering interactions with smoking status.

Main Results:

• The C allele correlated with higher baseline serum IL-6 levels.
• The CC genotype showed a high prevalence of CVD.
• C allele carriership predicted increased all-cause mortality in non-smokers, independent of other factors, but not in smokers.

Conclusions:

• The IL-6 -174G>C polymorphism is an independent predictor of all-cause mortality in octogenarians.
• This predictive effect is complex and significantly interacts with smoking status.
• Genetic predisposition to higher IL-6 may influence mortality risk differently based on lifestyle factors like smoking.