Type 2 diabetes mellitus and glucose intolerance have been shown to be risk factors for pancreatic cancer, but it is not clear whether diabetes is involved in pancreatic carcinogenesis or is the result of a subclinical malignancy. Data from a prospective study of the cohort of 29,133 male Finnish smokers enrolled in the α-Tocopherol, β-Carotene Cancer Prevention (ATBC) study between 1985 and 1988 now show that high concentrations of insulin or insulin resistance are associated with a high risk of pancreatic cancer in men.
The investigators hypothesized that diabetes mellitus might be involved in pancreatic carcinogenesis through the growth-regulatory effects of insulin, concentrations of which are increased in the early stages of diabetes mellitus. Insulin is known to have growth-promoting and mitogenic effects on pancreatic cancer. This case–cohort prospective study included 400 randomly sampled control participants and 169 incident pancreatic cancers that occurred after the fifth year of follow-up in the ATBC trial (to reduce the possibility of a subclinical cancer being present before the study began). The presence of biochemically defined diabetes mellitus (glucose ≥126 mg mL−1) and an insulin concentration in the highest quartile showed a twofold increased risk of developing pancreatic cancer.
