Researchers from the National Cancer Institute in Rockville, Md., found a connection between an increased risk of pancreatic cancer and increased insulin levels and resistance.
Previous studies have reported type 2 diabetes and glucose intolerance to be risk factors for pancreatic cancer; However, it has been unresolved whether diabetes mellitus is involved in pancreatic carcinogenesis or the result of subclinical malignancy. Experimental studies show that insulin has growth-promoting effects on pancreatic cancer cells, and patients with type 2 diabetes mellitus are known to exhibit hyperinsulinemia during the early stages of their disease.
Rachael Z. Stolzenberg-Solomon, Ph.D., and her team evaluated male smokers who participated in the Alpha-Tocopherol, Beta-Carotene Cancer Prevention (ATBC) Study to determine whether fasting serum insulin and glucose concentrations were associated with risk for incident pancreatic cancer. Of the 29’133 male Finnish smokers (ages 50-69 years) of the ATCB study, 400 randomly sampled subcohort control participants and 169 incident pancreatic cancer cases occurring after the 5th year of follow-up were included in the National Cancer Institute study.
Results showed that after adjustment for age, years smoked and BMI, higher concentrations of glucose, insulin, and insulin resistance tended to show positive dose-response associations with pancreatic cancer: Diabetes mellitus and insulin concentration in the highest quartile demonstrated a 2-fold increased risk. Moreover, risks were greater among the cases that occurred with longer follow-up time.
The researchers concluded that ‘our results support the hypothesis that higher insulin concentrations and insulin resistance may be a mechanism that explains the associations between diabetes mellitus, higher glucose concentration, and pancreatic cancer observed in previous studies. Although based solely on male smokers, our findings for glucose and biochemical-defined diabetes mellitus are consistent with previous studies conducted in diverse populations that have included women and nonsmokers.’
The study has been published in the Journal of the American Medical Association (2005;294:2872-2878).
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