Study Questions Cancer Risk in Workers Exposed to Acrylonitrile

Newswise — On-the-job exposure to the chemical acrylonitrile does not increase the long-term risk of brain cancer or any other type of cancer, reports a study in the June Journal of Occupational and Environmental Medicine, official publication of the American College of Occupational and Environmental Medicine (ACOEM). The new research adds to previous studies—now totaling nearly 40,000 workers—that have consistently found no increased cancer risk with acrylonitrile exposure, the authors conclude. Led by epidemiologist Gerard M.H. Swaen of University of Maastricht, The Netherlands, the researchers analyzed long-term follow-up data on over 2,800 employees at Dutch chemical plants in which acrylonitrile was used. The potential exposure to acrylonitrile occurred between 1958 and 1980. Rates and causes of death were compared with those of nearly 4,000 workers from a fertilizer plant, who were not exposed to acrylonitrile. Workers exposed to acrylonitrile were not at increased risk of any type of cancer. Some specific types of cancer occurred at somewhat higher rates in acrylonitrile-exposed workers, while others occurred at lower rates. None of these relationships were statistically significant, however. Further analyses were performed to compare the effects of different levels and durations of acrylonitrile exposure. Even in the most highly exposed workers, there was no significant increase in cancer risk. Analysis of respirator use or exposure to other potential carcinogens (cancer-causing substances) also found no effect on cancer risk. Acrylonitrile is used in a wide range of industries, including production of fibers, resins, and plastics. Past studies have raised concerns that this chemical may lead to increased cancer risks. Very high levels of acrylonitrile have caused brain cancers and other types of cancers in animals, while studies in workers exposed to acrylonitrile have suggested possible increases in brain and lung cancers. However, the new results—in a large group of workers with long-term follow-up—finds no increase in cancer risk among acrylonitrile-exposed workers. Dr. Swaen and colleagues acknowledge that the epidemiologic data cannot exclude "any imaginable cancer risk." However, together with previous studies including thousands of exposed workers, their results add to the evidence that "acrylonitrile is not a potent carcinogen." ACOEM, an international society of 6,000 occupational physicians and other healthcare professionals, provides leadership to promote optimal health and safety of workers, workplaces, and environments.