Cancer incidence and mortality in the occupational cohort of a German toxic waste landfill: a retrospective cohort study

BACKGROUND: Employees at the Ihlenberg toxic waste landfill in northern Germany were found to have an increased risk of cancer and cancer-related deaths in previous analyses covering the time period from 1983 to 2008. The present study aimed to quantify cancer risk and all-cause mortality in the employee cohort in 2009 to 2021.

METHODS: In this retrospective cohort study, cancers were identified by linkage with cancer registries, and employee deaths were obtained from population registries. Standardized incidence ratios (SIRs) for cancers and standardized mortality ratios (SMRs) were calculated to quantify cancer and mortality risk in the employee cohort. The effects of employment duration and different latency periods up to 30 years were additionally considered.

RESULTS: The cohort of 590 employees (432 men, 158 women) who worked at the landfill for at least 3 months between 1983 and 2018 was established from human resource management documentation and followed from January 1, 2009 until December 31, 2021. During this follow-up period, the SIR for all cancers combined was 0.69 (95% confidence interval (CI): 0.47, 0.98) and the SMR for all-cause mortality was 0.51 (95% CI: 0.35, 0.73). Longer employment at the landfill was not associated with increased cancer incidence or mortality.

CONCLUSIONS: Employment at the landfill, expected to reflect occupational exposure to toxic waste, was not associated with increased cancer incidence or mortality in the employee cohort. Preventive measures to reduce exposure and to promote a healthy lifestyle should be maintained at the landfill.