Systemic immune-inflammation index is associated with white matter hyperintensity volume

Systemic immune-inflammation index (SII) is a novel inflammatory marker based on the composition ratio of blood cell counts. In this study, we evaluated the association between the SII and cerebral small vessel disease (cSVD) in health check-up participants. We evaluated participants from our health check-up registry between 2006 and 2013. The SII was calculated using the following formula: SII = (platelet count x neutrophil count)/lymphocyte count. cSVD was assessed by considering white matter hyperintensity (WMH) volume, lacunes, and cerebral microbleeds (CMBs). A total of 3187 participants were assessed. In multivariable linear regression analysis, the SII was significantly related to WMH volume [beta = 0.120, 95% confidence interval (CI) 0.050-0.189]. However, lacunes and CMBs showed no statistical significance with the SII. In the subgroup analysis by age, the SII was significantly associated with WMH volume only in participants aged >= 60 years (beta = 0.225, 95% CI 0.068-0.381). In conclusion, a high SII was associated with cSVD. Since this association was more pronounced in WMH than in lacunes or CMBs, WMH might be closer to the inflammation-related pathological mechanisms.

Automated summary

This study evaluated the association between the systemic immune-inflammation index (SII) and cerebral small vessel disease (cSVD). The results showed a significant correlation between high SII and white matter hyperintensity (WMH) volume, but no significant correlation with lacunes or cerebral microbleeds (CMBs). Subgroup analysis by age revealed that SII was only significantly associated with WMH volume in participants aged ≥ 60 years.