Obesity is linked to diabetes
The factors that lead to diabetes may also put a person at increased risk of pancreatic cancer, research suggests.
The US National Cancer Institute found high insulin levels and increased resistance to the hormone were associated with a higher cancer risk.
They say their findings suggest adopting a healthy diet and lifestyle may help to reduce the risk of pancreatic cancer.
Details are published by the Journal of the American Medical Association.
The findings confirm previous studies which have linked type 2 diabetes to pancreatic cancer.
Insulin is a hormone produced by the pancreas
It controls the breakdown of sugars in the body
When the body's cells become resistant to the hormone sugar is not broken down as effectively as usual, and levels begin to rise
Insulin resistance precedes the development of type 2 diabetes
The researchers say it is possible that insulin in higher than normal levels may trigger the growth of pancreatic cancer cells.
The early stages of type 2 diabetes are often associated with raised levels of the hormone.
The researchers reviewed data on 29,133 male smokers from Finland, who were followed for up to 16 years.
They found those people with the highest concentrations of glucose and insulin and the highest levels of insulin resistance were more at risk of pancreatic cancer.
The researchers say follow-up studies are required to confirm the findings.
But writing in the journal, they say: "Lifestyle changes to decrease glucose and insulin concentrations through weight reduction, increasing physical activity, and diet such as decreasing saturated fat intake, and identification of other modifiable factors that may contribute to higher glucose and insulin concentrations could possibly impact pancreatic cancer development, as well as other cancer and chronic disease."
Henry Scowcroft, of the charity Cancer Research UK, said: "The most important risk factor for pancreatic cancer is smoking, which is thought to be linked to a third of all cases of the disease.
"We have known for some time that there's also a link between pancreatic cancer and diabetes but it hasn't been clear whether the diabetes causes the cancer, or vice versa.
"This paper supports the idea that having type 2 diabetes makes you slightly more likely to develop pancreatic cancer.
"But it's important to stress that this is a very small increase in risk - the vast majority of people with type 2 diabetes will never develop cancer of the pancreas."
A spokesperson for the charity Diabetes UK said any potential link between type 2 diabetes and pancreatic cancer would be worrying.
"This is something that requires further study.
"In the meantime people should look to their level of physical activity and their diet.
"Improvements in lifestyle can reduce the risk of serious health problems such as type 2 diabetes and other conditions that can be associated with it."