People who consume soft drinks on a regular basis are also more likely to have poorer lifestyles, but links between sugar-sweetened beverages on pancreatic cancer do have some biological plausibility, according to findings published in Cancer Epidemiology, Biomarkers & Prevention.
“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 Mark Pereira, PhD, from the University of Minnesota.
According to Cancer Research UK, over 230,000 people were diagnosed with pancreatic cancer worldwide in 2002. Survival rates for the cancer are relatively poor: Despite a doubling in survival rates since the 1970s, Cancer Research UK states that only 13 per cent of people survive beyond a year following diagnosis. According to the American Association for Cancer Research, only 5 per cent of people who are diagnosed are alive five years later.
Intrigue and caution
Commenting independently on the results, Susan Mayne, PhD, from the Yale School of Public Health and an member of the journal’s editorial board, described the results as intriguing. However, Mayne noted key limitations that should be considered in any interpretation.
“Although this study found a risk, the finding was based on a relatively small number of cases and it remains unclear whether it is a causal association or not. Soft drink consumption in Singapore was associated with several other adverse health behaviours such as smoking and red meat intake, which we can’t accurately control for,” said Mayne.
The statements of caution were echoed by Jessica Harris, health information officer at British charity Cancer Research UK. “Although this study included a lot of people, very few of them developed pancreatic cancer so it is difficult to know if soft drinks do increase the risk of pancreatic cancer, or whether the results are just down to chance,” said Harris.
“Also, people who drank lots of fizzy drinks in this study were more likely to be unhealthy in other ways, like smoking, eating more calories, and being less active, so it is difficult to separate the effects of all of these things,” she said.
Harris added that the evidence in this area is still inconsistent, with some previous studies reporting a similar link between soft drinks and pancreatic cancer, while others have not. “Even so, it’s important to remember that people can put on weight if they drink lots of sugary, fizzy drinks and being overweight increases the risk of lots of different types of cancer including bowel and breast cancers,” said Harris.
Dr Pereira and his co-workers analysed dietary data from 60,524 men and women participating in the Singapore Chinese Health Study. Over 14 years of follow-up, 140 pancreatic cancer cases were documented.
Data showed that people who consumed two or more soft drinks per week (averaging five per week) had an 87 percent increased risk compared with non-consumers. The results from Singapore are likely applicable to the United States, said Pereira.
“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.
Source: Cancer Epidemiology, Biomarkers & Prevention
Published online ahead of print, doi: 10.1158/1055-9965.EPI-09-0862
“Soft Drink and Juice Consumption and Risk of Pancreatic Cancer: The Singapore Chinese Health Study”
Authors: N.T. Mueller, A. Odegaard, K. Anderson, J.-M. Yuan, M. Gross, W.-P. Koh, M.A. Pereira