Association between blood lead levels and serum creatinine: a cross-sectional study.

Purpose: The aim of this cross-sectional study was to investigate the association between blood lead levels and serum creatinine.

Methods: In the present study, sample data were derived from the National Health and Nutrition Examination Survey (NHANES) 2015-2018 of participants with complete data of blood lead levels and serum creatinine. Multivariate linear regression models were used to examine the association between blood lead levels and serum creatinine. The nonlinear connection was described using fitted smoothing curves and threshold effect analysis. Furthermore, subgroup analyses and interaction tests were performed.

Results: A total of 9026 participants were enrolled in this study, and the mean serum creatinine for all subjects was 0.86 ± 0.34 mg/dL. When blood lead levels were divided into quartiles, it was found that participants' serum creatinine levels gradually increased with increasing blood lead levels (Q1: 0.77 ± 0.19 mg/dL, Q2: 0.84 ± 0.23 mg/ dL, Q3: 0.89 ± 0.34 mg/dL, Q4: 0.94 ± 0.50 mg/dL). Compared to the lowest serum quartile, the highest quartile of blood lead levels had a positive correlation with serum creatinine in the fully adjusted model (β = 0.05 95% CI 0.01-0.08). Smooth curve fittings and threshold effect analysis showed an inverted J-shaped nonlinear relationship between blood lead levels and serum creatinine, with an inflection point of 3.10 (μg/dL). Subgroup analyses and interaction tests revealed that diabetes mellitus impacted the relationship between serum creatinine and blood lead levels.

Conclusion: This study suggests a positive correlation between blood lead levels and serum creatinine.