Medicine
Pesticide exposure and colorectal cancer risk
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Ainhoa Pérez
Alumni
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MPH, MSc.
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Colorectal cancer is one of the most prevalent malignant neoplasms globally, causing high mortality worldwide. In addition to genetic and lifestyle risk factors, exposure to chemicals has attracted attention in the field of environmental epidemiology. Agricultural practices aimed at increasing productivity often involve excessive use of pesticides and herbicides, which pose significant threats to human health. These processes can induce genetic mutations through direct DNA damage, activate oncogenes, inhibit programmed cell death, alter hormone regulation, produce epigenetic changes, alter the microbiota, etc., contributing to the initiation and progression of cancer.
A recent meta-analysis (Xie et al., 2024) examined the relationship between pesticide exposure and the risk of developing different types of colorectal cancer. Thirty-three epidemiological studies with diverse designs were selected that compared individuals exposed to different pesticides versus unexposed or less exposed individuals, conducted in different countries up to 2023. Exposure was mainly assessed using self-administered questionnaires, but also through blood samples, work records, or industrial monitoring. Occupational and environmental exposure were separated, and different indices of "total sum of exposure days" and/or "weighted sum of exposure days" were used, which consider the intensity of contact.
The results from studies that used the "total sum of exposure days" and/or "weighted sum of exposure days" indices found that people exposed to herbicides had a higher risk of developing colon cancer, with the risk increasing when exposure intensity was taken into account. Exposure to insecticides was also associated with an increased risk of colon cancer, increasing the risk by 32%. In addition, exposure to insecticides was associated with a higher risk of rectal cancer compared to those who were never exposed, a risk that increased when the days and intensity of exposure were considered. It is important to note that almost all of the studies included referred to populations with occupational exposure. Most of the data came from the Agricultural Health Study, a large prospective cohort study designed to examine the potential health effects of pesticide exposure in the United States. The methodological quality has significant limitations in terms of sample size, heterogeneity in exposure assessment methods, lack of adjustment in some studies for confounding factors, and variability in study designs. In addition, several studies had a high risk of bias.
In conclusion, this meta-analysis suggests that exposure to herbicides and insecticides increases the risk of colon and rectal cancer. Despite the associations observed, different exposure assessment methodologies produce conflicting results that limit the generalizability of the findings. Therefore, research using more accurate exposure assessment methods is needed to better understand this relationship. Nevertheless, these findings underscore the need for stricter oversight of pesticide use to minimize health risks.
A recent meta-analysis (Xie et al., 2024) examined the relationship between pesticide exposure and the risk of developing different types of colorectal cancer. Thirty-three epidemiological studies with diverse designs were selected that compared individuals exposed to different pesticides versus unexposed or less exposed individuals, conducted in different countries up to 2023. Exposure was mainly assessed using self-administered questionnaires, but also through blood samples, work records, or industrial monitoring. Occupational and environmental exposure were separated, and different indices of "total sum of exposure days" and/or "weighted sum of exposure days" were used, which consider the intensity of contact.
The results from studies that used the "total sum of exposure days" and/or "weighted sum of exposure days" indices found that people exposed to herbicides had a higher risk of developing colon cancer, with the risk increasing when exposure intensity was taken into account. Exposure to insecticides was also associated with an increased risk of colon cancer, increasing the risk by 32%. In addition, exposure to insecticides was associated with a higher risk of rectal cancer compared to those who were never exposed, a risk that increased when the days and intensity of exposure were considered. It is important to note that almost all of the studies included referred to populations with occupational exposure. Most of the data came from the Agricultural Health Study, a large prospective cohort study designed to examine the potential health effects of pesticide exposure in the United States. The methodological quality has significant limitations in terms of sample size, heterogeneity in exposure assessment methods, lack of adjustment in some studies for confounding factors, and variability in study designs. In addition, several studies had a high risk of bias.
In conclusion, this meta-analysis suggests that exposure to herbicides and insecticides increases the risk of colon and rectal cancer. Despite the associations observed, different exposure assessment methodologies produce conflicting results that limit the generalizability of the findings. Therefore, research using more accurate exposure assessment methods is needed to better understand this relationship. Nevertheless, these findings underscore the need for stricter oversight of pesticide use to minimize health risks.
#Risks #cancer #pesticides #xenobiotics #disruptors
References:
Xie PP et al. Exposure to pesticides and risk of colorectal cancer: A systematic review and meta-analysis. Environ Pollut. 2024 Mar 15;345:123530. doi: 10.1016/j.envpol.2024.123530.
* The news published on studies do not represent an official position of ICNS, nor a clinical recommendation.
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