One sugary drink a day linked to more than double the risk of stomach cancer

The researchers found that people who consumed sugar-sweetened beverages every day were more likely to develop gastric cancer than those who rarely drank them. Artificially sweetened beverages, however, were not linked to an increased risk. The findings were published in the journal Gastro Hep Advances.

A Long-Term Look at Sugary Drinks and Cancer

Earlier research has connected sugar-sweetened beverages with higher risks of colorectal, breast, and liver cancers. Until now, however, relatively little was known about whether these drinks might also be associated with gastric cancer.

To investigate, researchers examined data from 112,284 participants enrolled in the Nurses' Health Study and Health Professionals Follow-Up Study. These long-running studies collected detailed information about participants' diets, lifestyles, and health over several decades. During the follow-up period, which also extended across decades, 278 participants developed gastric cancer.

"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, MD, MPH, a gastroenterologist and epidemiologist with the Mass General Brigham Cancer Institute. "Gastric cancer is the fifth leading cause of cancer death worldwide, but we've known very little about how diet might contribute to this cancer."

Daily Sugary Drinks Linked to 2.45 Times Higher Risk

After the researchers adjusted for other factors that could influence gastric cancer risk, they found a striking difference between frequent and infrequent consumers.

Participants who drank at least one serving of a sugar-sweetened beverage each day had a 2.45 times higher risk of developing gastric cancer than participants who consumed less than one serving per month. The association appeared in both women and men.

Higher overall fructose consumption (fructose is the main sweetener in these drinks) was also associated with a greater incidence of gastric cancer.

Among women in the Nurses' Health Study, for example, consuming more than one sugar-sweetened beverage per day was associated with a 3.04-fold higher risk of gastric cancer compared with women who very rarely consumed these beverages.

The pattern was different for artificially sweetened drinks. After researchers accounted for other potential factors, greater consumption of artificially sweetened beverages was not associated with a higher incidence of gastric cancer.

For the study, sugar-sweetened beverages included carbonated beverages, punch, lemonade and sports drinks. Artificially sweetened beverages were defined as low-calorie carbonated beverages.

Researchers Examined H. pylori Infection

The researchers also explored whether Helicobacter pylori (H. pylori) might help explain the findings. Infection with this bacterium is a known risk factor for gastric cancer.

H. pylori status was available for a subset of 940 participants. Slightly more than one third showed evidence of infection, but the researchers found no association between sugar-sweetened beverage consumption and H. pylori infection.

Why the Findings Do Not Prove Cause and Effect

The researchers cautioned that the study was observational, meaning it can identify associations but cannot establish that sugar-sweetened beverages directly cause gastric cancer.

Other factors could have contributed to the higher cancer rates seen among people who consumed more sugary beverages. The researchers also had limited information about participants' H. pylori status and family histories of gastric cancer.

Another limitation was the study population. Participants were predominantly white, making it difficult to determine whether the association differs across racial and ethnic groups.

At the same time, the study included a large number of participants and drew on detailed health, diet, and lifestyle information collected over many years. This allowed researchers to account for many other possible risk factors for gastric cancer.

Further research will be needed to confirm the results and determine why sugar-sweetened beverages might be associated with a greater risk of gastric cancer.

Authorship: In addition to Chan, Mass General Brigham authors include Tae-Geun Gweon, Jane Ha, Hanseul Kim, Mengxi Du, and Mingyang Song.

Funding: This work was supported by R35 CA253185, U01 CA261961, R01CA263776, and a Stand Up to Cancer Gastric Cancer Interception Dream Team award.

Disclosures: Chan served as a consultant for Pfizer Inc. and Boehringer Ingelheim and received grant support from Freenome Holdings outside the submitted work.