Are Bad Diets Causing a Bowel Cancer Crisis Among Millennials?
‘Things,’ that age old dictum goes, were always harder back in the day. That was of course before we had climate change and an impending new wave of fascism in the West. Suddenly “back in the day” seems to have nothing on what is to come. Need extra convincing? How about this new study, which reports a “sharp rise” in colorectal cancer among young adults in their 20s and 30s.
The study, led by scientists from the American Cancer Society, compared the colorectal cancer (CRC) incidence rates of people born around 1950, when risk was at its recorded lowest, with those born in 1990. Their overall findings, published late February in the Journal of the National Cancer Institute, showed that “three in ten rectal cancer diagnoses are now in patients younger than age 55.”
This statistic reflects a disturbing trend: the incidence of CRC, which had previously been decreasing for people born between 1890 and 1950, has steadily increased in each consecutive generation born ever since. What’s most concerning is that scientists can’t explain why.
Here is what they do know. Recent studies had begun reporting an increase in CRC incidence among adults under 50. To better understand this, the American Cancer Society researchers decided to conduct a “retrospective study” of all patients—measured in 5-year age group increments—that were diagnosed with CRC from 1974 through 2013. For the study, they used the “the nine oldest Surveillance, Epidemiology, and End Results (SEER) program registries,” which included 490,305 cases. The team also made sure to use a research model that removed extraneous factors, such as changes in medical practice, when comparing their data.
Their results revealed that incidences of colon cancer have risen the fastest among people aged 20-29. Specifically, they found that this rate has grown by 2.4 percent per year since 1974. A similar rising trend was observed among people in their 30s and 40s. For rectal cancer, the rate was recorded as rising at 3-4 percent per year for adults in their 20s. By contrast, rates of rectal cancer in adults 55 and older have generally been in decline for the past 40 years.
“There is no mistaking these dramatic increases, especially for rectal cancers,” Dr. Thomas Weber, a professor of surgery at SUNY Downstate Medical Center, told the New York times. Although Weber himself was not involved in the study, he has served on the National Colorectal Cancer Roundtable and confirmed that the study’s findings show a very real and increasing trend. He added that the number of new CRC patients under 50 each year now exceeds the “total number of new cases” of other less common cancers. This article further emphasizes that “colorectal cancers are considered a disease of aging.” The fact that there has been a decrease in the rates of this disease among older people, “is both baffling and worrisome.”
It’s important to note at this point the full implications of these findings. As Dr. Gilbert Welch, a professor of medicine at the Dartmouth Institute, explained in an interview with CNN, the number of actual increased cases of CRC among young people still remains relatively low. What is concerning, however, is that there are more cases among young people now than there were before, which translates to more serious stages of the cancer later on in life if these sections of the population continue to go unscreened.
In terms of accounting for this increase, the researchers were unable to provide an exact cause. In a statement to the press, though, they did note how, “it is not surprising that the timing of the obesity epidemic parallels the rise in colorectal cancers because many behaviors thought to drive weight gain, such as unhealthy dietary patterns and sedentary lifestyles, independently increase colorectal cancer risk.”
Dr. Rebecca Siegel, the lead author on this study, explained how this could be the case by citing a different study that found people from Africa who suddenly switched to an American diet showed signs of inflammation in their colons within just two weeks. "So this change can happen fairly rapidly," she said.
The link between dietary habits and CRC is of course nothing new. Previous research has found that diets comprised of fast food meals, or really any foods containing high sugar content, can increase the risk of CRC. A large consumption of alcohol, as well as smoking, are also big contributors.
In the same Times article, Dr. Mohamed E. Salem, an assistant professor at Lombardi Comprehensive Cancer Center at Georgetown University, confirmed that at age 42 he was older “than about 60 percent of his patients.” Although obesity is a factor of concern among the scientific community, Salem said, “we suspect there is also something else going on.”
The question of possible causes was explored further in a recent article by Richard Harris published on NPR. The article cited a different, British study that suggested that “only 11 percent of colon cancer cases could be tied to trends in obesity.” Welch offered his own possible explanation to NPR, saying how this trend might simply be reflective of the fact that people are receiving colonoscopies for more reasons nowadays, and, as a result, doctors are “coming upon early cases of colon cancer that might not have turned up so soon.” To that end, Harris referenced a different study which shows that although the rate of new CRC cases has increased among Americans aged under-50, the death rate has remained relatively the same.
"Trends in young people are a bellwether for the future disease burden," said Siegel, in her statement to the press. For Siegel, the results of their study should prompt a rise in awareness among “clinicians and the general public” in order to “reduce delays in diagnosis” as well as “encourage healthier eating and more active lifestyles to try to reverse this trend."
One practical suggestion made by Siegel and her team is lowering the average risk age for screening people for CRC. More generally, Siegel urges doctors and patients to become more aware of possible signs and symptoms. She lists these warning signs as follows:
- A change in bowel habits, such as diarrhea, constipation, or narrowing of the stool, that lasts for more than a few days.
- A feeling that you need to have a bowel movement that is not relieved by doing so
- Rectal bleeding
- Dark stools, or blood in the stool
- Cramping or abdominal (belly) pain
- Weakness and fatigue
- Unintended weight loss
In an article published on the American Cancer Society’s website, Dr. Otis Brawley, the society’s chief medical officer, listed several practical ways young people could mitigate their chances of being diagnosed with CRC.
- Eat lots of vegetables, fruits, and whole grains and less red meat (beef, pork, or lamb) and processed meats (hot dogs and some luncheon meats).
- Get regular exercise.
- Watch your weight.
- Avoid tobacco.
- Limit alcohol. The American Cancer Society recommends no more than 2 drinks a day for men and 1 drink a day for women.
Yes, there is a lot to possibly fear about the future. There is also a lot we can do now to avoid those fears. Think about the environment, think about your health. Be proactive now, and who knows, we may just be able to one day complain again about how much harder things used to be.