Adolescents and young adults drink more sugar-sweetened beverages than any other demographic group. Rates of colon cancer in people under 50 have also been edging up in recent years. Could there be a connection?

In a study published in the journal Gut, researchers at the Washington University School of Medicine in St. Louis, analyzing data from a longstanding study of female nurses, report that a penchant for sugary drinks, such as soda and fruit juice, is associated with an increased risk for colon cancer among women. The finding may help resolve a longstanding medical mystery, suggest researchers.

“Colorectal cancer in younger adults remains relatively rare, but the fact that the rates have been increasing over the past three decades—and we don’t understand why—is a major public health concern and a priority in cancer prevention,” senior study author Yin Cao, ScD, an associate professor of surgery and medicine in the division of public health sciences, said in a press release from the Washington University School of Medicine.

The researchers analyzed data on 95,464 of the 116,4329 women who participated in the Nurses’ Health Study II, one of the largest investigations into the risk factors for major chronic diseases in women. The women, who are nurses, are predominantly white and were between ages 25 and 42 when they enrolled in 1989. The women provided information about their diet every four years, and slightly fewer than half of them (41,272) also provided information about their diet during adolescence. During that time, 109 were diagnosed with early-onset colon cancer. The results revealed the following:

  • Women who consumed two or more sugary drinks per day were more than twice as likely to be diagnosed with early-onset colon cancer—defined as colon cancer that develops before age 50—than those who consumed one or fewer sugary drinks per week.
  • Each sugary drink consumed daily in adulthood was associated with a 16% higher likelihood of being diagnosed with early-onset colon cancer.
  • A teenage habit was an even greater risk: Each sugary drink consumed daily between ages 13 and 18 was associated with a 32% higher likelihood of being diagnosed with early-onset colon cancer, according to Medical News Today.
  • By contrast, consuming sugary drink “alternatives”—including milk, coffee and artificially sweetened drinks—was linked to lower risk. Each alternative beverage consumed daily in adulthood was associated with a 17% to 36% lower likelihood of being diagnosed with early-onset colon cancer.

Sugary drinks may contribute to colon cancer by increasing the risk for developing type 2 diabetes as well as overweight and obesity, both of which are risk factors for several types of cancer, including colon cancer. The researchers also hypothesize that the corn syrup in sugary drinks may promote abnormal cell division, giving rise to tumors.

While the results don’t establish cause and effect, the researchers note that other reasons to modify sugar intake abound. “On top of the well-known adverse metabolic and health consequences of sugar-sweetened beverages, our findings have added another reason to avoid sugar-sweetened beverages,” coauthor Yin Cao, an associate professor of surgery at the Washington University School of Medicine, told HealthDay News. “Reducing sugar-sweetened beverage intake and/or replacing sugar-sweetened beverages with other, healthier beverages would be a better and wiser choice for long-term health.”

“Clearly, more research is needed before we can give this a stamp of approval and say with confidence that this association is actually causation,” Will Bulsiewicz, MD, a South Carolina–based gastroenterologist who was not involved with the study, told HealthDay News. However, he added, “No one thinks sugar-sweetened beverages are health-promoting, [and] you should reduce your sugar-sweetened beverage intake as much as possible.”

For more on how consuming sugary drinks could adversely affect your health, read “Could Your Daily Orange Juice Be Increasing Your Cancer Risk?” and “Sugary Drinks and Trans Fats Increase Risk of Death From Fatty Liver Disease.” To learn more about colon cancer in people under 50, see “Interview: How to Save a Life From Colorectal Cancer.”