Experts have raised concerns that chemicals in food, air, and water could be fueling a global surge in colon cancer cases among young people.
In the United States, the rate of colorectal cancer diagnoses in individuals in their 20s and 30s is projected to skyrocket by 90% by 2030.
While factors like obesity and unhealthy diets have been implicated, they do not fully explain why healthy individuals are increasingly being affected.
A review of over 160 studies has turned the spotlight on environmental pollutants, including pesticides, toxins in drinking water, and air pollution, as potential contributors to this alarming trend.
The researchers argue that a “complex interplay” of these factors disrupts gut bacteria, triggering chronic inflammation that damages healthy cells and fosters the growth of cancerous ones.
The review suggests that this wave of early-onset colorectal cancer has been decades in the making, with increased exposure to pollutants traced back to the 1950s.
The researchers emphasized the need for stricter environmental policies to reduce exposure, protect public health, and curb the rising burden of EOCRC.
They stated, “Consequently, there is a pressing need for enhanced environmental policies aimed at minimizing exposure to pollutants, safeguarding public health, and mitigating the burden of EOCRC.”
Published in Heliyon, the review highlights how gastrointestinal health depends on the gut microbiome—a network of bacteria essential for the digestive and immune systems.
Over time, exposure to factors like processed foods, antibiotics, and chemicals can destabilize this ecosystem, allowing harmful bacteria to outnumber beneficial ones.
To examine the surge in colorectal cancer among younger generations, the researchers analyzed environmental exposures in individuals born after 1950.
They identified fine particulate matter (PM2.5), tiny particles emitted from fossil fuel combustion, as a significant factor.
These microscopic particles bypass the body’s natural filters, enter the bloodstream, and cause inflammation, which can lead to cancer.
A 2020 study involving nearly 60,000 adults in Thailand revealed that PM2.5 exposure from soot and dust increased the risk of early-onset colorectal cancer by up to 15%.
In the U.S., southeastern and Appalachian states, including West Virginia, Kentucky, and Louisiana, where PM2.5 levels are highest, also report some of the nation’s highest rates of EOCRC.
The review also notes a sharp rise in pesticide use, which has increased fiftyfold since 1950.
For instance, by 1982, 95% of cornfields were treated with pesticides, compared to just 10% in 1952. Research indicates that as many as 80% of Americans have detectable pesticide levels in their blood.
The study highlights concerns about the widespread dispersal of pesticides into air, water, and soil.
“The use of pesticides presents environmental challenges as a significant portion drifts away from their intended target, accumulating in unintended species, air, water, and soil,” the researchers noted.
They also pointed out findings showing a 73% higher correlation between pesticide use and colorectal cancer compared to smoking.
Pesticides may increase cancer risk by acting as endocrine disruptors—chemicals that mimic hormones like estrogen and testosterone, interfering with natural hormonal functions and potentially causing genetic mutations linked to colorectal cancer.
The researchers further examined water contamination, particularly with heavy metals such as lead and arsenic.
Despite widespread acknowledgment that no amount of lead exposure is safe, an estimated nine million lead pipes remain in use across the U.S. Corroded plumbing can release lead into tap water, exposing individuals through everyday activities like drinking, showering, and dishwashing.
Once in the body, lead can accumulate in organs such as the liver, kidney, and lungs, impairing their functions and increasing cancer risk.
The International Agency for Research on Cancer classifies lead as a “probable” carcinogen. Studies indicate that lead in the bloodstream can travel to the colon, killing healthy cells and potentially leading to cancer.
Data from the Environmental Protection Agency reveals that states like Alaska, New Mexico, and Louisiana, which reported the most water quality violations between 2019 and 2023, also have high rates of EOCRC.
While these findings shed light on potential links between environmental pollutants and early-onset colorectal cancer, the researchers acknowledged limitations in the study.
Many of the studies reviewed were observational and did not establish direct causation. Furthermore, more research is needed to pinpoint specific gut microbes that increase cancer risk.
“These findings highlight the need for more research into the specific environmental factors and their epigenetic impacts, to inform prevention and treatment strategies for EOCRC,” the team concluded.
