The health effects of low blood lead level in oxidative stress as a marker, serum gamma-glutamyl transpeptidase level, in male steelworkers

Abstract

Background: This study aimed to investigate the association between lead exposure and serum gamma-glutamyl transpeptidase (γGT) levels as an oxidative stress marker in male steelworkers.

Methods: Data were collected during the annual health examination of workers in 2020. A total of 1,654 steelworkers were selected, and the variables for adjustment included the workers' general characteristics, lifestyle, and occupational characteristics. The association between the blood lead level (BLL) and serum γGT level was investigated by multiple linear and logistic regression analyses. The BLL and serum γGT values that were transformed into natural logarithms were used in multiple linear regression analysis, and the tertile of BLL was used in logistic regression analysis.

Results: The geometric mean of the participants' BLLs and serum γGT level was 1.36 μg/dL and 27.72 IU/L, respectively. Their BLLs differed depending on age, body mass index (BMI), smoking status, drinking status, shift work, and working period, while their serum γGT levels differed depending on age, BMI, smoking status, drinking status, physical activity, and working period. In multiple linear regression analysis, the difference in models 1, 2, and 3 was significant, obtaining 0.326, 0.176, and 0.172 (all: p < 0.001), respectively. In the multiple linear regression analysis stratified according to drinking status, BMI, and age, BLLs were positively associated with serum γGT levels. Regarding the logistic regression analysis, the odds ratio of the third BLL tertile in models 1, 2, and 3 (for having an elevated serum γGT level within the first tertile reference) was 2.74, 1.83, and 1.81, respectively.

Conclusions: BLL was positively associated with serum γGT levels in male steelworkers even at low lead concentrations (< 5 μg/dL).

Keywords: Gamma glutamyl transpeptidase; Lead; Occupational exposure; Oxidative stress.

Fig. 1. Flowchart of the inclusion process in the study population.

HBV: hepatitis B virus; HCV: hepatitis C virus; USG: ultrasonography.

Fig. 2. OR (95% CI) for having elevated serum γGT levels according to BLLs after covariate adjustment.

Model 1 was crude model; Model 2 was adjusted for age, body mass index, smoking status, drinking status and physical activity; Model 3 was adjusted for age, body mass index, smoking status, drinking status, physical activity, shift work, working period, co-exposure to mercury or cadmium, and co-exposure to hepatotoxic substances. BLL: blood lead level; CI: confidence interval; γGT: gamma-glutamyl transpeptidase; OR: odds ratio; T: blood lead level tertile.