New research from the US that studied the diet and health outcomes of over half a million people suggests that high consumption of dietary fat, especially from red meat and dairy food, is linked to an increased risk of pancreatic cancer.

However, some experts suggest that while this is a good study that contributes to our understanding of the disease, it does not prove a link with animal fats per se (it could be some other dietary or lifestyle factor that is common to people who eat lots of animal fat) and that more work is needed before we can be sure.

The study was the work of Dr Rachael Z Stolzenberg-Solomon, from the Division of Cancer Epidemiology and Genetics at the National Cancer Institute in Bethesda, Maryland, and colleagues and was published in the advanced access online issue of the Journal of the National Cancer Institute on 26 June 2009.

In their background information, Stolzenberg-Solomon and colleagues wrote that they decided to carry out the investigation because up to now research on the link between pancreatic cancer and dietary fat, a risk factor that people can do something about, has been inconclusive.

For this prospective study (ie one that follows a certain group over a period of time) the researchers used data from the National Institutes of Health AARP Diet and Health Study, a large US-based group of 308,736 men and 216,737 women aged 50-71 years who filled in a 124-item food frequency questionnaire in during 1995 and 1996.

The group was then followed for an average of 6.3 years to see what happened to their health, including whether any were diagnosed with pancreatic cancer.

After that, the researchers used statistical tools to search for any links between fat consumption, including different types of fat and where it came from, and pancreatic cancer, while taking into account potential confounders like smoking/not smoking, body mass index (BMI), and diabetes.

The key results showed that:

* 865 men and 472 women developed pancreatic cancer (an incident rate 45.0 and 34.5 cases per 100 000 person-years, respectively).

* Men and women with the highest total fat consumption were 53 per cent and 23 per cent more likely to receive a pancreatic cancer diagnosis than with men and women with the lowest fat consumption.

* There were positive links between pancreatic cancer and intakes of total, saturated and monounsaturated fat overall.

* The links were strongest for those whose fat came primarily from red meat and dairy foods.

* Those who consumed high levels of saturated fats had were 36 per cent more likely to develop pancreatic cancer than those who consumed low levels.

The authors wrote that:

"We did not observe any consistent association with polyunsaturated or fat from plant food sources."

They concluded:

"In this large prospective cohort with a wide range of intakes, dietary fat of animal origin was associated with increased pancreatic cancer risk."

"Altogether, these results suggest a role for animal fat in pancreatic carcinogenesis," they wrote.

In an editorial in the same issue of the journal, Drs Brian M. Wolpin from the Dana Farber Cancer Institute in Boston, and Meir J Stampfer from the Harvard School of Public Health, also in Boston, said this was a well-performed study that contributed to our understanding of pancreatic cancer, but there wasn't enough information to be sure that it was animal fats or fat from red meat that was linked to pancreatic cancer and not something else that is common to people who eat lots of red meat and animal fats.