Supplementary Material for: Associations between total Immunoglobulin E levels and Urinary Albumin Excretion: A Cross-sectional Study

Introduction.
The association between total immunoglobulin E (IgE) levels and urinary albumin excretion has not been fully established. Current study aims to evaluate the association between total IgE levels and urinary albumin-to-creatinine ratio (UACR) among adult Americans.
Methods.
Current cross-sectional study utilized data from the 2005-2006 National Health and Nutrition Examination Survey, including individuals aged 20 years and above. To assess the relationships between total IgE levels and UACR, both multivariable linear regression models and smooth curve fitting were employed.
Results.
The study included a total of 3,400 participants (weighted mean age: 46.6±0.8 years), with 1,625 females (weighted percentage: 47.8%). After adjusting for potential confounders, we observed a positive association between higher total IgE levels on a log2 scale and increased UACR (β=3.34; 95% CI, 1.40–5.28, p=0.002). Furthermore, the association displayed a non-linear dose-response pattern. The interaction test revealed a significant distinction in the correlation between total IgE and UACR when stratified by hyperlipidemia (p for interaction <0.001). The results remained robust in sensitivity analyses.
Conclusion.
Our study revealed a significant and independent association between elevated total IgE levels and an increased UACR, which also exhibited a distinct non-linear pattern, highlighting the intricate nature of the connection between IgE levels and UACR.