Impact of Occupational Lead Exposure on Lung Cancer Risk in Korean Male Workers: A Retrospective Cohort Study

In 2006, the IARC reported that inorganic lead is carcinogenic in animals but with limited evidence in humans. In addition, some studies have reported that exposure to lead increases the risk of lung cancer, but this remains controversial. Therefore, we aimed to assess the risk of developing lung cancer according to blood lead levels in workers with occupational lead exposure.

A retrospective cohort study of male workers with 2009 blood lead (PbB) concentrations was conducted using nationwide special health examination data (SHED) from 2009 to 2021 and cancer registry data from 1999 to 2020 from the Republic of Korea. Standardized incidence ratios (SIRs) for lung cancer risk at each PbB level were calculated with a five-year wash-out period, adjusting for age, smoking status, duration of exposure, and the number of co-exposures to lung carcinogens.

The study included 26,092 workers with an average follow-up period of 9.98 years. Compared with workers with PbB levels <3.130 µg/dL, the adjusted SIRs for lung cancer risk were 2.95 (95% confidence interval [CI]: 1.47-5.27) and 3.13 (95% CI: 1.82-5.00) for workers with PbB levels of 3.130-4.899 and ≥4.900 µg/dL, respectively, indicating a significant dose-response trend.

This study demonstrates a significant association between lead exposure and an increased risk of lung cancer, highlighting the need for stronger occupational health policies and ongoing monitoring of workers exposed to lead. The observed dose-response relationship underscores the importance of reassessing current occupational safety standards and strengthening measures to reduce lead exposure in the workplace.