EPFL student applies engineering to public health

Noé Fellay has always been someone who wants to know how things work – and how to fix them. As a child he tinkered with objects at home, such as a broken water sprinkler, and developed a curiosity about how nature works. Today he regularly returns to his home canton of Valais and its wild scenery. Given these interests, it’s no surprise that Fellay chose to study environmental engineering at EPFL, although he briefly considered a career in medicine. When it came time to pick a topic for his Master’s project, Fellay set his sights high – he decided to apply spatial analysis techniques to the field of public health, with the goal of evaluating the presence in a given population of an autoantibody known to be associated with cardiovascular disease. He used Lausanne as his case study. Fellay’s cross-disciplinary project was carried out in the GEOME research group at EPFL’s Laboratory for Biological Geochemistry (LGB) and was supervised jointly by Stéphane Joost, a senior scientist at LGB, and Prof. Nicolas Vuilleumier at the Geneva University Hospitals (HUG). “It was the perfect project for me since I’ve always enjoyed geographical modeling and am still interested in medical research,” says Fellay.

Autoantibodies and cadmium

To conduct his study, Fellay started by obtaining medical data from cohort studies and using them to map regions of Lausanne with the highest blood concentrations of the AAA1 autoantibody, which is a harmful autoantibody against apolipoprotein A-1 – the protein that carries HDL cholesterol (also known as “good cholesterol”) in the bloodstream. High AAA1 levels can cause inflammation and lead to atherosclerosis, making it a risk factor for cardiovascular disease. Blood concentrations of AAA1 are affected by genetic factors, but they can also be influenced by environmental ones. For instance, scientists now know that exposure to heavy metals such as cadmium, lead and arsenic, even at very low levels, could be a cause of cardiovascular disease.

For his study, Fellay used spatial analysis to evaluate the correlation between heavy metals and cardiovascular disease in Lausanne. He looked specifically at cadmium, which is released from the friction caused by train brakes, train wheels running along the tracks and overhead lines rubbing against electrical wires.

Clusters near train stations

Fellay used data from the CoLaus-PsyColaus cohort study conducted among Lausanne residents between 2003 and 2006. He found clusters of individuals with high AAA1 blood concentrations, such as in the western part of the city. Fellay then examined the cadmium exposure of Lausanne residents as determined by the presence of cadmium in their urine (which reflects long-term exposure). He produced a map showing three areas of the city where high AAA1 blood concentrations were significantly associated with elevated cadmium levels. These three areas corresponded perfectly to the locations of three train stations: Sébeillon (now defunct but still in operation when the data were collected), the main Lausanne train station, and the Chandieu marshaling yard. This made sense since studies have shown that soil concentrations of cadmium tend to be higher along train tracks.

Incorporating other factors

In light of Fellay’s findings, EPFL decided to hire him on a contract running until December so that he can complete his research. Fellay is now in the process of examining data he wasn’t able to analyze earlier. The next step will be to incorporate other factors that may be at play, such as air pollution and socioeconomic status. Fellay also plans to disseminate his findings this fall through an article to be published jointly by EPFL and HUG. The hope is that the information will help government officials design more effective measures for protecting public health. For Fellay, the article will be the culmination of a project that combines his engineering studies and his initial interest in medicine.