Relationship between the systemic immune inflammation index and prostate cancer.

The association between systemic immune inflammatory index (SII) values and prostate cancer remain poorly understood. This study aimed to estimate the association between SII values and the risk of prostate cancer by analyzing the statistics on 10,485 participants in the National Health and Nutrition Examination Survey from 2011 to 2018. The quartile (Q) method was used to divide the participants into 4 groups on the basis of their SII values, from group Q1 (lowest SII values) to group Q4 (highest SII values). The association between the participants' SII values and the risk of prostate cancer was analyzed using weighted logistic regression models and a restricted cubic spline, and further subgroup analysis was conducted by age, body mass index; ethnicity; education level; and smoking, alcohol-drinking, hypertension, hyperlipidemia, and diabetes status. Higher SII values were found to be associated with a higher risk of prostate cancer. In comparison with Q1, the odds ratio of Q4 was 2.26 (95% confidence interval: 1.44-3.55). Subgroup analysis revealed that this positive association was more significant among non-Hispanic black participants than among other participants. In addition, the results of a sensitivity analysis demonstrated that the association between the risk of prostate cancer and the SII values was relatively stable. The SII values were found to be positively associated with the risk of prostate cancer and varied with ethnicity. Nevertheless, further prospective studies are required to confirm these findings.