Human body maintains a record of all environmental exposures, from pollutants to diet and stress. Analysing the record, dubbed exposome, can help in precise prediction of the risk of diseases a person faces. Stephen Rappaport, director of the Berkeley Center for Exposure Biology in USA, spoke to Shruti Chowdhari about the possibility
What is exposome?
Exposome is the record of every interaction an individual has with his or her environment since conception. These interactions could be external, such as exposure to air and water pollution and diet, or internal such as the body’s response to infection or psychological stress.
Unlike genetic factors that account for 10-30 per cent of disease risks, environmental factors account for 70-90 per cent of these risks. Identifying these factors would help us monitor one’s exposure to them and determine the risk level.
Need for measuring exposome
At present, epidemiologists use questionnaire to understand one’s exposure level to certain pollutants. They ask people to identify their exposures, even those which occurred long in the past. Such self-reported data does not yield accurate and sufficient information to pinpoint environmental exposures. Moreover, chronic diseases are not caused by a single factor.
Internal factors like immune responses also act as hallmarks of biological changes. Blood samples can be scanned for chemical signatures of external as well as internal factors.
Possibilities and challenges
Strategies can be developed for getting snapshots of critical portions of one’s exposomes during different stages of life, such as foetal stage, puberty and early adulthood. All classes of toxicants that cause diseases— such as reactive electrophiles, hormone disruptors, modulators of immune responses and metals—can be measured in an individual’s blood at different stages of life. Additional tests can determine their sources and methods to reduce them.
The challenge lies in characterising the exposome, meaning identifying the multitude of disease-causing factors that one gets exposed to during one’s lifetime. This is the same kind of challenge the human genome project faced when DNA sequencing was in its infancy.
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