From Genome to Exposome: Environmental Determinants of Global Health

March 25, 2019

Is human growth determined more by our genetic makeup or by environmental nurture?  Even as this question has been the source of serious scholarly debate over the years, it gains added significance when making critical decisions about health care.  

Presenting the Yusuf Hamied Distinguished Lecture at the Columbia Global Centers | Mumbai on March 4, 2019, Gary Miller, Vice Dean and Professor of Environmental Health Sciences at Columbia University’s Mailman School of Public Health, demonstrated how the study of the human genome and genetics has now been expanded by a new and complex set of diagnostic measures classified as the exposome

The term ‘exposome’ was coined in 2005 by Dr. Christopher Wild, a molecular epidemiologist.  It aimed to fill a gap that was remained unaddressed by the study of the genome that is relatively steady in one’s lifetime.  For instance, while trying to understand contributors to cancer, epidemiological data do not provide sufficient information about environmental drivers of the disease.  Professor Miller defined the exposome as the “cumulative measure of environmental influences and associated biological responses throughout the lifespan, including exposures from the environment, diet, behavior, and endogenous processes.”  In his seminal work, The Exposome: A Primer (2013), he writes that “It is odd that that the majority of discussion of Darwin occurs amongst geneticists when natural selection is primarily driven by the environment. The environment viz the exposome is what is driving natural selection. If one removes external forces acting upon our genome, evolution would grind to a halt.”

Yusuf Hamied

Professor Miller’s lecture cited research studies that had benefited from exposome testing.  An example he offered was from his recent project with the Mayo clinic where he conducted research on primary sclerosing cholangitis.  Samples from 200 patients revealed many changed metabolites, which were a result of exogenous and endogenous factors. Chemicals from the environment such as pesticides and personal care products were found to have a considerable effect on the disease. The study led to the identification of over 200 chemical biomarkers.

The importance of the exposome in toxicology and medicine is gradually gaining ground, as many universities from Europe and the United States are conducting research in this field. An increasing number of journal articles and projects are being published.  Yet if diverse communities in Asia and other parts of the world are to benefit from technological advances in health through precision diagnosis and treatment, greater investment and a collaborative international effort is needed with leading research institutes and scholars.