Association of systemic immune inflammatory index with obesity and abdominal obesity: A cross-sectional study from NHANES

Abstract

Background and aim: Our aim was to explore the potential relationship between SII and obesity, as well as abdominal obesity.

Methods and results: We utilized a weighted multivariable logistic regression model to investigate the relationship between SII and obesity, as well as abdominal obesity. Generalized additive models were employed to test for non-linear associations. Subsequently, we constructed a two-piecewise linear regression model and conducted a recursive algorithm to calculate inflection points. Additionally, subgroup analyses and interaction tests were performed. A total of 7,880 U.S. adult participants from NHANES 2011-2018 were recruited for this study. In the regression model adjusted for all confounding variables, the odds ratios (95% confidence intervals) for the association between SII/100 and obesity, as well as abdominal obesity, were 1.03 (1.01, 1.06) and 1.04 (1.01, 1.08) respectively. There was a non-linear and reverse U-shaped association between SII/100 and obesity, as well as abdominal obesity, with inflection points at 7.32 and 9.98 respectively. Significant positive correlations were observed before the inflection points, while significant negative correlations were found after the inflection points. There was a statistically significant interaction in the analysis of age, hypertension, and diabetes. Moreover, a notable interaction is observed between SII/100 and abdominal obesity within non-Hispanic Asian populations.

Conclusions: In adults from the United States, there is a positive correlation between SII and the high risk of obesity, as well as abdominal obesity. Further large-scale prospective studies are needed to analyze the role of SII in obesity and abdominal obesity.

Keywords: Abdominal obesity; Cross-sectional study; NHANES; Obesity; Systemic immune-inflammation index.