Association between systemic inflammation and obesity-myopia comorbidity in adolescents: A cross-sectional analysis

This study aimed to investigate the association between systemic inflammation and the comorbidity of obesity and myopia among adolescents, focusing on the Systemic Immune-Inflammation Index (SII) and Systemic Inflammation Response Index (SIRI) as markers of inflammation.

This cross-sectional study utilized data from the National Health and Nutrition Examination Survey (NHANES) spanning 1999-2008. The associations between SII and SIRI and obesity-myopia comorbidity were evaluated using multivariable logistic regression, restricted cubic spline (RCS) modeling, and subgroup analyses.

A total of 8043 adolescents were included in this study. Multivariable logistic regression analysis indicated a significant positive association between both SII and SIRI, analyzed as continuous and quartile-based variables, and the likelihood of obesity-myopia comorbidity (p < 0.05). A dose-response relationship was observed, with the highest quartile of SII (Q4) associated with an odds ratio (OR) of 2.78 and the highest quartile of SIRI associated with an OR of 2.12. RCS analysis indicated significant nonlinear associations (SII: p_nonlinear < 0.001; SIRI: p_nonlinear = 0.001), suggesting that inflammation is positively associated with myopia after exceeding a critical threshold. Subgroup analysis demonstrated that these associations were statistically significant among adolescents with mild to moderate myopia, but not among those with high myopia. However, due to the non‑significant interaction term, these subgroup results should be considered exploratory analyses of this study.

The findings of this study indicate a nonlinear dose-dependent association between systemic inflammatory markers (SII and SIRI) and the comorbidity of obesity and myopia in adolescents. This association was particularly evident in adolescents with mild to moderate myopia. However, due to the cross‑sectional design and the exploratory nature of the subgroup analyses, causality cannot be established, and further research is needed for validation.