Does interleukin-18 or tumour necrosis factor-alpha have an independent association with the risk of coronary heart disease? Results from a prospective study in New Zealand.

BACKGROUND

The pro-inflammatory cytokines, interleukin (IL)-18 and tumour necrosis factor-alpha (TNFalpha) may play a role in coronary heart disease (CHD). We aimed to extend data on their relationships to the risk of CHD in generally healthy populations.

METHODS

During 5.5years follow-up in the Fletcher Challenge general population cohort there were 256 CHD cases, and 615 controls were matched for age and sex. Baseline plasma levels of IL-18 and TNFalpha were related to CHD risk in available samples (77%).

RESULTS

Plasma levels of IL-18 (11% increase in mean, p=0.01) and TNFalpha (10% increase in mean p=0.024) were significantly elevated in CHD cases versus controls. In univariable models IL-18 was associated with CHD risk (odds ratio [OR] upper third to lower third, 1.63; 95% CI 1.08, 2.46), but TNFalpha was not (OR 1.33; 95% CI 0.87, 2.02).After adjusting for major CHD risk factors and CRP, the association of IL-18 with CHD risk was attenuated (OR 1.69; 95% CI 0.94, 3.03).

CONCLUSIONS

IL-18, but not TNFalpha, had a non-negligible association with CHD risk, although the association of IL-18 with risk was weak after full adjustment. These cytokines may play a role in CHD pathology, but may not be robust risk biomarkers.