People who drank at least one sugar-sweetened beverage a day were more likely to develop stomach cancer than those who rarely drank them, according to a new observational study.
Researchers analyzed data from 112,284 adults in the Nurses’ Health Study and Health Professionals Follow-Up Study, two long-running U.S. cohorts that have collected detailed information on diet, lifestyle and health for decades. During follow-up, 278 participants developed stomach cancer.
After accounting for other potential risk factors, people who drank at least one sugar-sweetened beverage a day had about 2.5 times the risk of stomach cancer compared with those who drank less than one per month.
The findings, published in Gastro Hep Advances, do not show that sugary drinks caused stomach cancer. The number of stomach cancer cases was also small relative to the overall study population, which means the large relative increase in risk needs to be interpreted carefully.
“This is the first study to demonstrate an association between sugar-sweetened beverage intake and gastric cancer in a U.S. population,” said senior author Andrew T. Chan, a gastroenterologist and epidemiologist with the Mass General Brigham Cancer Institute.
Researchers defined sugar-sweetened beverages as drinks such as regular soda, punch, lemonade and sports drinks.
The association appeared in both men and women. Among women in the Nurses’ Health Study, drinking more than one sugary beverage a day was associated with about three times the risk of stomach cancer compared with drinking them very rarely.
Researchers also found that higher total fructose intake was associated with more stomach cancer cases. Fructose is one of the sugars commonly found in sweetened beverages.
By contrast, artificially sweetened beverages were not associated with a higher rate of stomach cancer in this study.
That finding should be interpreted narrowly. It does not show that artificial sweeteners are risk-free or settle broader questions about artificial sweeteners and cancer. It only means researchers did not find an association with stomach cancer in this analysis.
The study also looked at Helicobacter pylori, or H. pylori, a bacterial infection that is a major risk factor for stomach cancer. Researchers had information on H. pylori status for only a small subset of participants, however, so they could not fully account for it across the entire study population.
Among the 940 participants with available H. pylori data, researchers did not find an association between sugary drink intake and infection.
The authors noted several other limitations. The study was observational, which means other differences between people who drank sugary beverages frequently and those who rarely did could help explain the results. Participants were also predominantly white, limiting the researchers’ ability to examine whether the association differs across racial and ethnic groups.
Earlier research on sugary drinks and stomach cancer has not consistently found an increased risk, so the new results will need to be confirmed in other populations.
The study does, however, add to a growing body of research examining how beverage choices may relate to cancer risk. For now, the findings suggest that frequent sugary drink consumption may be associated with stomach cancer, but they do not establish that the beverages themselves caused the disease.
The study was supported by grants from the National Institutes of Health and a Stand Up To Cancer Gastric Cancer Interception Dream Team award. Senior author Andrew T. Chan reported consulting for Pfizer and Boehringer Ingelheim and receiving grant support from Freenome Holdings outside the submitted work.