The face of colorectal cancer getting younger, linked to obesity

By Nisa Islam Muhammad -Staff Writer- | Last updated: Oct 30, 2018 - 1:56:49 PM

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Could obesity be the cause of the rise in colorectal cancer in 20 and 30 year olds? A new study in the Journal of the American Medical Association (JAMA) found that obesity was associated with an increased risk of early-onset colorectal cancer among women.


“In a prospective cohort study of 85,256 women, those with obesity (body mass index greater than 30) had a nearly doubled risk of early-onset colorectal cancer (CRC) compared with women with a body mass index of 18.5 to 22.9,” authors wrote in the study released Oct. 11.

“The findings suggest that obesity is associated with an increased risk of early-onset colorectal cancer; further investigations are needed to identify whether this association is causal.”

The study began in 1989 and recruited 85,256 female nurses in the United States to participate. During the study, they were all between 25-42 years of age.

“In this large prospective study of women, we found that higher current BMI, BMI at 18 years of age, and weight gain since early adulthood were associated with increased risk of early-onset CRC,” explained study authors, Po-Hong Liu, M.D., MPH; Kana Wu, M.D., MPH, PhD and Kimmie Ng, M.D., MPH. 

Since 2017, researchers at the American Cancer Society have known that colorectal cancer was rising dramatically in younger generations. Between the mid-1990’s to 2013, for people in their 20s and 30s, colon cancer rates increased one to two percent. For the same age group, the rectal cancer rate rose three percent per year.

Overall, those born in 1990 have double the risk of developing colon cancer and four times the risk of getting rectal cancer compared to those born around 1950. Just one year later, in response to these alarming trends, the American Cancer Society lowered the age for routine colorectal cancer screening to 45 from 50.

“I have a patient right now with blood in their stool, and he’s only 32 years old,” Khalillah Ali, nurse practitioner at a family practice in Dallas, Texas, told The Final Call.  “People are breaking down faster.  Colon cancer used to be an older person’s disease.  We are seeing the results of people eating so much processed food.  People are not eating properly,” she said.

“Even those who are so-called vegetarians are eating too much processed foods.  I’m not surprised colorectal cancer is on the rise.  If you look at what people are eating.  Their diets are full of high sugar, high starch, and high carbohydrates.  It’s a diet of refined sugar and starches that causes obesity.  People also need to have regular bowel movements.  Obesity runs in the family too. It can be a generational problem,” she said.

The World Health Organization determined in 2015 that processed meat was a major contributor to colorectal cancer, classifying it as “carcinogenic to humans.” The equivalent of just one hot dog or a few strips of bacon consumed daily increases cancer risk by 18 percent.

There is a major campaign by the Physicians Committee for Responsible Medicine to get people to stop eating processed meat called “Break Up with Bacon.” Information about the campaign can be found at 

The study authors conceded that more research is needed to confirm whether obesity is truly a contributing factor to colorectal cancer.

“The association between obesity and increased risk of overall CRC diagnosed at a median of over 63 years of age has been well documented, with stronger and more consistent findings among men compared with women,” they explained.

“This study is among the first to investigate prospectively the association between obesity and risk of CRC diagnosed at younger than 50 years. Our additional analyses by age at onset indicates that obesity may play a substantial role in colorectal carcinogenesis among younger people and may contribute to the age-specific differences in CRC trends.”