Systemic inflammation and suicide risk: cohort study of 419 527 Korean men and women

BACKGROUND: Data from only one study have been used to examine the relationship between systemic inflammation and later suicide risk, and a strong positive association was apparent. More research is needed, particularly looking at gender, not least because women are seemingly more vulnerable to inflammation-induced mood changes than men. METHODS: The Korean Cancer Prevention Study had a cohort of over 1 million individuals aged 30–95 years at baseline examination between 1992 and 1995, when white blood cell count, our marker of systemic inflammation, was assessed. RESULTS: A mean of 16.6 years of mortality surveillance gave rise to 1010 deaths from suicide in 106 643 men, and 1019 deaths from suicide in 312 884 women. There was little evidence of an association between our inflammation marker and suicide mortality in men after multiple adjustments. In women, however, those in the second inflammation quartile and higher experienced around 30% increase risk of death (HR 1.35; 95% CI: 1.11–1.64). CONCLUSIONS: Higher levels of systemic inflammation were moderately related to an elevated risk of suicide death in women but not in men.