Objective To evaluate the effect of the interaction of occupational lead exposure with other occupational factors on arrhythmia in workers, identify potential risk factors, and protect the occupational health of lead-exposed workers.

Methods A cross-sectional study was conducted with 2 943 occupationally lead-exposed workers from the program of key occupational disease surveillance in Guangdong Province in 2021. Demographic characteristics and physical examination data were collected. A mixed-effects logistic regression model was used to evaluate the effect of lead exposure on arrhythmia. Further interaction analysis and subgroup analysis were conducted to explore potential susceptible populations.

Results The blood lead levels of these study subjects ranged from 14.14 to 582.23 μg/L. There were 915 individuals (30.09%) with abnormal blood lead levels. A total of 392 individuals had arrhythmia, with a prevalence of 13.32%. Males, workers in small-sized enterprises, private enterprises, and manufacturing industries; those aged > 37 years, with working time > 36 months, exposed to dust, exposed to noise, and with a history of arrhythmia accounted for a higher proportion of workers in the group with abnormal blood lead levels, and the differences were all statistically significant (all P < 0.05). Mixed effects logistic regression analysis showed that the risk of arrhythmia increased by 40.6% in workers for every one interquartile range (IQR) increase in blood lead level (OR = 1.406, P < 0.001) after controlling for other confounding factors. Subgroup analysis revealed that for every one IQR increase in blood lead level, the risk of arrhythmia increased by 43.9% (OR = 1.439, P < 0.001) in workers without dust exposure; the risk of arrhythmia increased by 46.2% (OR = 1.462, P < 0.001) in workers without sulfuric acid and sulfur trioxide exposure; and the risk of arrhythmia increased by 37.5% (OR = 1.375, P < 0.001) in workers without noise exposure. Among workers in private enterprises, the prevalence risk of arrhythmia increased by 41.3% (OR = 1.413, P < 0.001) for every one IQR increase in blood lead level. Among workers in foreign-invested enterprises, the prevalence risk of arrhythmia increased by 82.8% (OR = 1.828, P < 0.001) for every one IQR increase in blood lead level.

Conclusions There was a significant positive association between blood lead level and the risk of arrhythmia among lead-exposed workers, and this association was influenced by economic type and other occupational hazard factors.