According to Flood, it is not exactly clear what aspect of diabetes is the underlying cause for this increased risk, but one hypothesis centers on the elevated concentration of insulin typically seen in people with type II diabetes. In the early stages of the disease process, people become insulin resistant, meaning they must produce more and more insulin to regulate their blood sugar, Flood said.
Even after frank diabetes begins, insulin levels remain chronically elevated for extended periods before the pancreas can no longer supply the level of insulin the body demands, Flood said. If the elevated insulin is the problem, then pre-diabetics, who are also hyper-insulinemic, should also be at increased risk (for developing colorectal cancer).
To test that idea, Flood and his colleagues re-analyzed the data, this time including women who were likely pre-diabetic at the beginning of the follow-up period. The idea, Flood says, is that these women were likely hyper-insulinemic at that stage. Surprisingly, the elevated risk, while still significant, had dropped slightly in comparison with that of known diabetics, Flood says.
According to Flood, this suggests that either the pre-diabetic women had not had elevated insulin long enough or intensely enough to increase risk as they observed in the diabetic women, or alternatively, something other than or in addition to hyper-insulinemia could explain the significan
|Contact: Greg Lester|
American Association for Cancer Research