This research letter points toward the importance of studying ‘lifetime’ mixtures of chemical exposures to understand disease risk
In a research letter published in Gastroenterology, researchers at the Icahn School of Medicine at Mount Sinai explore the association between earlier chemical exposures, particularly mixtures of pesticides, and risk of inflammatory bowel disease (IBD), including Crohn’s disease (CD) and ulcerative colitis (UC).
Researchers utilized cutting-edge technology including gas chromatography coupled with high-resolution mass spectrometry (GC-HRMS), to analyze a wide range of chemicals in blood samples. Using samples collected at different time points from 1–10 years prior to IBD diagnosis, an untargeted chemical exposome analysis identified significant associations between increased risk of IBD and exposure to a mixture of chemicals, notably o-Hydroxybiphenyl, a pesticide. The risk was highest 6–10 years before diagnosis, suggesting a possible critical exposure window or lag period.
“While these data are consistent with other indirect reports on pesticides and IBD in the U.S. and abroad, to our knowledge, ours is the first study to measure serum levels of chemicals at multiple time points prior to IBD diagnosis,” said Manasi Agrawal, MD, MS, corresponding author and Assistant Professor of Medicine, Icahn School of Medicine at Mount Sinai.
“One of the striking findings was that the mix of chemicals was associated with risk at 6-10 years prior to diagnosis, and not at points much closer to diagnosis. This may suggest a biological sensitivity window of an exposure with a lag period. In addition, we believe that IBD may be a result of ‘multiple hits’ and downstream biological effects, which would explain the prolonged window between exposure and onset,” added Agrawal
“A long lag period can make study of chemical exposures prior to the onset of a health outcome challenging. It emphasizes the importance of studying ‘lifetime’ exposures longitudinally. Validation of our findings in external preclinical cohorts will help move the field forward,” said Dr. Agrawal.
“Studies like this point toward an urgent need for stricter policies and regulations for pesticide usage,” said Vishal Midya, PhD, MSTAT, senior author and Assistant Professor of Environmental Medicine, Icahn School of Medicine at Mount Sinai.
Featured Scientists:
Vishal Midya, PhD, MSTAT, Assistant Professor, Environmental Medicine, Icahn School of Medicine at Mount Sinai
Manasi Agrawal, MD, MS, Assistant Professor of Medicine, Icahn School of Medicine at Mount Sinai
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