Association between systemic immunity-inflammation index and glucose regulation in non-diabetic population: A population-based study from the NHANES (2005-2016)

Background To investigated the link between the systemic immunity-inflammation index (SII), a new inflammatory biomarker, and the risk of abnormal glucose regulation in non-diabetic population. Methods Using data from the 2005-2016 National Health and Nutrition Examination Survey (NHANES), we conducted a cross-sectional study on non-diabetic adults with data on SII and glucose regulation markers. We analyzed the relationship between SII and indicators of glucose regulation, including fasting plasma glucose, fasting insulin, hemoglobin A1c, oral glucose tolerance test (OGTT), and states of abnormal glucose regulation like impaired glucose tolerance (IGT), insulin resistance, and prediabetes. Results Adjusting for confounders, higher SII levels were significantly associated with a higher OGTT and a greater likelihood of IGT (OR = 2.673, 95% CI: 1.845, 3.873). In subgroup analysis, participants without hyperlipidemia in the highest SII quartile had a 240% higher odds of IGT compared to those in the lowest quartile (OR = 3.407, 95%CI: 1.995, 5.820), an association not observed in those with hyperlipidemia (p for interaction < 0.05). Conclusions SII emerges as a useful biomarker for identifying IGT in non-diabetic individuals, specifically in those without hyperlipidemia.