Long-term interleukin-6 levels and subsequent risk of coronary heart disease: two new prospective studies and a...

Area of Science:

• Cardiovascular Medicine
• Immunology
• Epidemiology

Background:

• Cytokines like interleukin-6 (IL-6) are involved in inflammatory processes relevant to coronary heart disease (CHD).
• The short-acting and fluctuating nature of IL-6 may lead to underestimation of its role in CHD.
• Assessing long-term IL-6 levels is crucial for understanding its association with CHD risk.

Purpose of the Study:

• To evaluate the association between long-term circulating IL-6 levels and CHD risk.
• To correct for within-person variability in IL-6 measurements using serial data.
• To contextualize findings within existing literature through a systematic review.

Main Methods:

• Analysis of serial IL-6 measurements in two population-based cohorts (24,230 participants).
• Correction for within-person variability using repeat measurements over several years.
• Updated systematic review of 15 previous studies on IL-6 and coronary outcomes.

Main Results:

• After correcting for variability, long-term average IL-6 showed an odds ratio of 2.14 (95% CI 1.45-3.15) per 2 SD increase for CHD.
• This association was comparable to established CHD risk factors.
• A meta-analysis of 17 studies yielded a combined odds ratio of 3.34 (95% CI 2.45-4.56) per 2 SD increase in usual IL-6 levels.

Conclusions:

• Long-term IL-6 levels are significantly associated with CHD risk, similar in strength to major established risk factors.
• The findings suggest the potential importance of IL-6-mediated inflammatory pathways in CHD.
• While causality remains uncertain, IL-6 represents a potential target for CHD prevention strategies.