Is cadmium a human carcinogen?

Area of Science:

• Occupational Health
• Environmental Toxicology
• Epidemiology

Background:

• Initial suspicions suggested a link between cadmium exposure and increased prostatic cancer mortality.
• Previous studies indicated a potential association between cadmium exposure and elevated lung cancer mortality.
• Confounding factors, including exposure to arsenic, nickel, beryllium, chromium, and heated mineral oils, complicated earlier interpretations.

Purpose of the Study:

• To re-evaluate the mortality risks associated with occupational cadmium exposure.
• To investigate the specific relationship between cadmium exposure intensity and lung cancer risk.
• To assess the impact of confounding factors, particularly arsenic exposure, on observed mortality trends.

Main Methods:

• Analysis of a long-term cohort mortality study involving workers from 17 plants in England.
• Inclusion of data from various cadmium processing operations.
• Assessment of exposure intensity to cadmium and other potential carcinogens, including arsenic.

Main Results:

• No evidence of increased mortality from prostatic cancer was found in cadmium-exposed workers.
• An increased mortality risk from lung cancer was observed, with a dose-response relationship suggested in some studies.
• The updated 17-plant study confirmed an increased lung cancer risk related to cadmium exposure intensity but also indicated a potential association with arsenic exposure.

Conclusions:

• Current evidence does not support an increased risk of prostatic cancer mortality due to cadmium exposure.
• The excess lung cancer mortality observed in cadmium-exposed workers cannot be definitively attributed to cadmium alone due to significant confounding factors.
• Further investigation is ongoing to elucidate the specific roles of cadmium and co-exposures, such as arsenic, in the observed lung cancer risks.