Researchers demystify link between esophageal cancer and soft drinks

04/01/06 Carbonated soft drink consumption was previously suggested to be linked to the 350 percent increase of adenocarcinoma of the esophagus since the mid-1970s, but researchers at Yale School of Medicine report that the link is unfounded and that there may, in fact, be a decreased risk of this cancer for diet soda drinkers.

The researchers warn that diet soft drink consumers might differ from other groups because they may engage in other unmeasured healthy behaviors. The study is published in the January 4 issue of Journal of the National Cancer Institute (JNCI).

It was hypothesized by others that carbonated soft drinks might have contributed to the development of adenocarcinoma of the esophagus. The theory was based on factors including similar time trends; acidic carbonated soft drinks causing gastric distension that might affect the lower esophagus; and association of carbonated soft drinks with heartburn at night, a known risk factor for esophageal adenocarcinoma.

"The theory that soft drinks could be causing this cancer was picked up by the media and widely disseminated," said lead author of the Yale study Susan Mayne, professor in the Department of Epidemiology and Public Health at Yale School of Medicine and associate director of the Yale Cancer Center. "However, there was no direct evidence to bear on this hypothesis, until we initiated our analysis."

Potential causes of esophageal adenocarcinoma were identified by Mayne and her colleagues in a previously completed population-based, multi-center study of 1,095 cancer patients and 687 control subjects. As part of that study, they conducted a full dietary interview and had access to available data on consumption of both regular and diet soft drinks.

The study was funded by the National Cancer Institute, and utilized the Rapid Case Ascertainment Shared Resource at the Yale Cancer Center.