Pancreatic cancer, which is usually fatal, is the fourth-leading cause of cancer deaths in the United States. Various risk factors for developing the disease have been identified, including smoking, diabetes and obesity. Some studies have also linked dietary fat to increased risk, but researchers said that data had been inconclusive.
However, Rachael Z. Stolzenberg-Solomon, from the institute's cancer epidemiology and genetics division, said the new study "found an association between high fat intake and pancreatic cancer risk -- specifically, high fat from animal foods."
"These findings are in line with the dietary guidelines for Americans to reduce the amount of fat they eat," she said. "Reducing fat may reduce the risk of pancreatic cancer."
The report is published online June 26 in the Journal of the National Cancer Institute.
The researchers collected data on more than a half-million people -- 308,736 men and 216,737 women -- who participated in the National Institutes of Health-AARP Diet and Health Study. All participants completed a 124-item food questionnaire in 1995 and 1996.
During an average of six years of follow-up, 1,337 people were diagnosed with pancreatic cancer. Men who consumed the most fat from animal sources had a 53 percent increased risk of developing pancreatic cancer and women had a 23 percent increased risk, compared with men and women who ate the least fat, the study found.
In addition, it found that people who ate high amounts of saturated fats had 36 percent higher rates of pancreatic cancer than did those who ate low amounts.
Dr. Brian M. Wolpin, and oncologist at the Dana-Farber Cancer Institute in Boston and co-author of an accompanying journal editorial, said the study might provide clues to the disease.
"We know very little about pancreatic cancer and what the causes are, and we don't do a very good job treating it," Wolpin said.
He noted that in addition to the possibility of a link between pancreatic cancer and fat, there are other good reasons to limit consumption of red meat and animal fat, including an increased risk for other cancers.
People who eat a lot of red meat tend to engage in other unhealthy lifestyle behaviors, Wolpin said. "Whether it's red meat or a constituent of red meat or your overall lifestyle that matters, these studies cannot tease out to a convincing extent," he said. "But it's clear that lifestyle does impact this disease."
Eric J. Jacobs, strategic director of pharmacoepidemiology at the American Cancer Society, said that the study "provides important evidence that a diet high in animal fat may increase risk of one of the leading causes of cancer death."
"While further confirmatory research about animal fat and pancreatic cancer is still needed, results of this study support the American Cancer Society's recommendations to limit red meat and emphasize plant foods to help reduce risk of a variety of cancers," Jacobs said.
In addition to diet, weight appears to be a risk factor for pancreatic cancer.
Research reported in the June 24 issue of the Journal of the American Medical Association found that being overweight or obese as a young adult increases the risk for pancreatic cancer, and obesity in middle age is linked with poorer survival from the disease.
Being overweight in your 30s was associated with a 60 percent increased risk for pancreatic cancer, and being obese was associated with a twofold to threefold higher risk, the researchers found.
"Something associated with obesity apparently drives pancreatic cancer," said Dr. Robert R. McWilliams, an oncologist at the Mayo Clinic and co-author of a JAMA editorial on the study. "As a scientific community, we need to understand the underlying mechanism. Hopefully, this can lead to future treatment strategies."