A new study found that people who consumed two or more soft drinks (defined as sugar-sweetened carbonated beverages) a week, had a nearly two-fold higher risk of developing pancreatic cancer; the researchers suggested regular consumption of sweetened beverages could raise insulin levels and thereby fuel the growth of pancreatic cancer cells.

You can read about the study online in a paper published in the February issue of Cancer Epidemiology, Biomarkers & Prevention, a journal of the American Association for Cancer Research.

Senior author Dr Mark Pereira, associate professor in the School of Public Health at the University of Minnesota in Minneapolis and colleagues, followed over 60,000 Singapore-based men and women for over a decade and found that compared to those who did not consume soft drinks, those who had two or more a week had two times the risk of developing pancreatic cancer.

They found no such link for fruit juice consumption.

Pereira told the press that while the population they studied was based in Singapore, the results were likely to be equally applicable to the US and other developed countries:

“Singapore is a wealthy country with excellent health care. Favorite pastimes are eating and shopping, so the findings should apply to other western countries,” said Pereira.

Dr Susan Mayne, who is an associate director of the Yale Cancer Center and professor of epidemiology at the Yale School of Public Health, and also on the editorial board of the journal, said the study was intriguing but people should be aware of its limitations and bear them in mind when interpreting the findings.

Mayne cautioned that although Pereira and colleagues established a risk, it was based on a relatively small number of cases (despite the large cohort), and it is not clear whether the link reflects cause and effect or not:

“Soft drink consumption in Singapore was associated with several other adverse health behaviors such as smoking and red meat intake, which we can’t accurately control for,” she warned.

But Pereira argued that the findings were biologically plausible, were the same for non-smokers, stayed similar after controlling for other dietary habits and were consistent with findings in Caucasian populations.

He agreed that while people who regularly consume carbonated sugar-sweetened beverages tend to have a poor overall health behavior profile, he thinks that the effect of these drinks on pancreatic cancer may be unique:

“The high levels of sugar in soft drinks may be increasing the level of insulin in the body, which we think contributes to pancreatic cancer cell growth,” said Pereira.

Although quite rare, pancreatic cancer has a poor survival rate: only 5 per cent of people diagnosed with it live more than 5 years. One of the reasons is that early symptoms are often overlooked and as they progress they are varied and non-specific so that by the time it is diagnosed the cancer has already become advanced.

According to aNational Cancer Institute (NCI) estimate, over 42,000 men and women were diagnosed with pancreatic cancer and over 35,000 die from it in the US last year.

For the study, Pereira and colleagues followed 60,524 men and women taking part in the Singapore Chinese Health Study for 14 years during which time 140 cases of pancreatic cancer were diagnosed.

After adjusting for potential confounders, they found that those who consumed two or more soft drinks a week (average of 5 per week) had an 87 per cent higher risk of developing the cancer than those who did not (hazard ratio was 1.87 with a 95 per cent confidence interval ranging from 1.10 to 3.15).

The researchers wrote that they found “no statistically significant association between juice consumption and risk of pancreatic cancer”.

They concluded that:

“Regular consumption of soft drinks may play an independent role in the development of pancreatic cancer.”

“Soft Drink and Juice Consumption and Risk of Pancreatic Cancer: The Singapore Chinese Health Study.”
Noel T. Mueller, Andrew Odegaard, Kristin Anderson, Jian-Min Yuan, Myron Gross, Woon-Puay Koh, and Mark A. Pereira.
Cancer Epidemiol Biomarkers Prev February 2010 19:447-455.

Related article:

Pancreatic Cancer Linked To Poor Oral Hygiene (January 2007).

Sources: AACR, NCI, MNT archives.

Written by: Catharine Paddock, PhD