Project 460903

Whether it be in the food we eat, the water we drink, or the things we encounter daily, toxins (e.g., lead, cadmium, and BPA) in varying amounts and kinds are often ingested. As such, regardless of our lifestyles, we all have some amount of circulating toxins. Despite the ubiquitous nature of toxin exposure, there is limited research into determining if they are causally linked to increased cancer risks. The reason is two-fold. Firstly, for ethical reasons, human studies in this area are largely dominated by observational data which can be strongly affected by biases introduced through confounding factors such as lifestyle. Secondly, animal and cellular model studies often have had poor translation to human outcomes. My research project aims to overcome both limitations by utilizing an established technique known as Mendelian Randomization (MR) applied to data collected through the Canadian Health Measures Survey (CHMS). The CHMS is a federally led project that currently has standardized toxin data from over 13,000 Canadians. MR, sometimes known as "nature's randomized control trial", is a powerful alternative to the gold standard, the double-blind randomized controlled trial, to assess the causal role of toxins and cancer risk. MR makes use of the fact that all toxins, once enter the body, are processed by various proteins and due to natural variations in our DNA, our ability in doing so differs between people. This means that simply because of genetics, some people are naturally prone to higher levels of circulating toxins. Since our genetics are determined at birth, they are independent of common confounding factors. Using these genetic determinants of toxin levels as statistical instruments, I will use MR to test if a causal relationship between toxin exposure and cancer risk exists. Such information will help us better understand which toxins should be avoided and will help to shape future public health policies to reduce the cancer burden in Canada.