Twenty-Year Longitudinal Cohort Study of Cancer Incidence and Mortality Among Workers in Two Primary Aluminum Prebake...

Classified as carcinogenic to humans by the International Agency for Research on Cancer, aluminum production has been transitioning towards lower polycyclic aromatic hydrocarbon-emitting prebake smelters. This study explored the risk of cancer and mortality over 20 years follow-up among a cohort of aluminum prebake smelter workers.

Time-weighted average estimated exposure to the following airborne contaminants was available: total fluoride, sulfur dioxide, asbestos, oil mist, inhalable dust, benzene (a) pyrene (BaP), and benzene soluble fraction (BSF). Data about diagnosed cancers were accessed from the Australian Cancer Database and deaths and cause of deaths from the National Death Index, updating a previous linkage 9 years earlier.

The cohort included 4495 male smelter workers. Mesothelioma was associated with historic asbestos exposure. BaP/BSF exposure were found associated with stomach cancer (10-year lag RR = 2.89 (1.19-6.98) [BaP], 2.88 (1.21-6.87) [BSF]), liver and prostate cancers, and Alzheimer's disease mortality. Oil mist exposure was associated with chronic obstructive pulmonary disease (COPD) mortality. There was no association between any smelter exposure and incidence of either lung or bladder cancer.

In this updated linkage of aluminum prebake smelter workers' data, the association between respiratory cancer and fluoride, inhalable dust and BaP exposure (found in the 2002 linkage analysis) was not confirmed. There was also no increased incidence of bladder cancer. However, compared with the earlier linkage, a stronger association was found for stomach cancer and BaP/BSF exposure. The strong association between mesothelioma and asbestos exposure, found in earlier linkages, remains. Other associations identified will require further investigation.