Abstract
OBJECTIVES: This study aims to investigate the potential relationship between low-level lead exposure and serum gamma-glutamyl transferase (GGT) concentrations, which may serve as a biomarker of oxidative stress in U.S. adolescents. METHODS: We used NHANES data from 1999 to 2000 to 2017-2018. Analyses were limited to adolescents aged 12-19 years with blood lead levels (BLLs) below 5 µg/dL (n = 11,978). BLLs were categorized into either two groups based on the median BLL (i.e., <0.70 µg/dL and ≥0.70 µg/dL) or four quartiles (i.e., quartile 1: <0.46 µg/dL; quartile 2: 0.46-<0.70 µg/dL; quartile 3: 0.70-<1.00 µg/dL; and quartile 4: ≥1.00 µg/dL). Multivariable linear regression analysis was conducted to assess the association between BLLs and serum GGT concentrations among U.S. adolescents aged 12-19 years. RESULTS: Adolescents with BLLs ≥ 0.70 µg/dL showed significantly higher serum GGT concentrations compared to those with BLLs < 0.70 µg/dL (geometric means: 13.94 vs. 12.80 U/L; p < 0.001). The multivariable linear regression analysis indicated that, after adjusting for potential confounding factors, natural log-transformed serum GGT concentrations were higher among adolescents in BLL quartile 4 compared to those in BLL quartile 1 (β-coefficient = 0.0607; 95% CI: 0.0306, 0.0908). However, no significant associations were observed between BLLs and serum GGT concentrations among adolescents in BLL quartiles 2 and 3 when compared to quartile 1. CONCLUSIONS: In the present study, we observed that higher BLLs were associated with higher serum GGT concentrations in U.S. adolescents aged 12-19 years. Further research is needed to substantiate the positive relationship between BLLs and serum GGT and explore the mechanisms underlying their interaction with oxidative stress in adolescents.