A unique 17-year cancer prevention project has ruled out vitamin A as an effective protection against asbestos-related cancer. The Vitamin A project, led by renowned clinician Professor Bill Musk, involved nearly 2,500 former workers from Wittenoom, where deadly blue asbestos was mined and milled from 1943 to 1966.
The program was launched in 1990 after several international studies reported evidence of vitamin A’s anti-cancer benefits. The first group, 928 people, received Vitamin A in the form of retinol or beta-carotene, while 1471 people in the control group received no supplements.
Those who received retinol were younger, had a greater exposure to asbestos and smoked less than the comparison group.
After five years of follow-up, a significantly lower number of mesothelioma cases were diagnosed among the participants taking retinol compared with those taking beta-carotene and the researchers decided to abandon beta-carotene, cease randomisation and place all of those in the non-control group on retinol.
By the end of the study in October 2007, 88 participants in the control group and 65 people in the Vitamin A group had been diagnosed with malignant mesothelioma.
The research team has reported in the European Journal of Cancer Prevention that after adjusting for the cumulative asbestos exposure and age at entry to the program, there was no significant difference in the incidence of mesothelioma between those who received Vitamin A and those who took nothing.
“In conclusion, this study provides little support for possible preventive effects of retinol against mesothelioma in workers exposed to blue asbestos,” the report said.
“In view of the current results, provision of retinol has also been stopped in the absence of evidence of a sustained protective effect.”
By Catherine Madden