Occupational Exposure to Endocrine Disrupting Chemicals and Colorectal Cancer Risk

Principal Investigator: Dr. Vikki Ho & Dr. Jack Siemiatycki

Affiliation: Centre de recherche du centre hospitalier de l’Université de Montréal (CHUM)

Start Year: 2018

Worldwide, colorectal cancer is the third most common cancer with over 1.2 million new cases occurring annually. Men experience higher rates of colorectal cancer than women. Environmental, behavioural and biological factors likely all contribute to the differential risk. Recent advances in our understanding of the molecular biology of colorectal cancer, particularly with respect to the estrogen hormone and its metabolism in the colon, have implicated the role of sex hormones. Specifically, results from randomized controlled trials reported that women who take hormone replacement therapy experience lower colorectal cancer risk. These findings implicate the role of sex hormones in colorectal cancer etiology.

Endocrine disrupting chemicals are exogenous substances that cause adverse health effects through interference with the endocrine system whose function includes the production of sex hormones. Exposure to endocrine disrupting chemicals occurs through occupational, dietary and environmental sources. However, non-occupational exposures do not represent a major source of exposure among those occupationally-exposed; a comparison of reported biomarker levels of selected endocrine disrupting chemicals revealed that concentrations of these chemicals are between 9 to 45 times higher in occupationally-exposed workers than the general population.

Endocrine disrupting chemicals may act as antagonists to the proper functioning of sex hormones, thereby reducing the levels/activity of sex hormones. This research proposes to investigate the role of exposure to endocrine disrupting chemicals in the development of colorectal cancer by studying occupational exposures to these chemicals. This research will reveal the importance of occupational exposures and hormonal influences in colorectal cancer etiology.