A review of data on nearly 20 million people has concluded that having diabetes significantly raises the risk of developing cancer.

For women the risk is even higher, not just of cancer but also leukemia and cancers of the stomach, mouth and kidney. Men, however, had less risk for liver cancer. If none of that makes sense, you see the flaws in replacing science with epidemiological statistics.

Diabetes affects up to 415 million people worldwide, with estimates of up to five million deaths each year. The problem in the new paper is blanket acceptance of speculation that  heightened blood glucose may have cancer-causing effects by leading to DNA damage, and seeking to show it with statistics rather than biology.

Their statistics:

Women with diabetes were 27 percent more likely to develop cancer than women without diabetes. For men the risk was 19 percent higher. Like smoking, obesity and age are risk factors for developing cancer. That they correlate it instead to diabetes - which type 2 diabetics likely got because of obesity - makes little sense.

The difference between men and women with diabetes for developing cancer of the kidney was 11 percent, oral cancer was 13 percent, stomach cancer was 14 percent, leukaemia was 15 percent higher - but for liver cancer the risk for women was actually 12 percent lower. Which makes no biological sense. 

Will gender specific research matter?

The authors say the findings highlight the need for more research into the role diabetes plays in developing cancer and demonstrate the increasing importance of sex specific research, but it reads more like a populist appeal. There is no evidence that doing sex-specific research on diabetes will keep anyone from getting leukemia or liver cancer.

Women with diabetes were only six percent more likely overall to develop any form of cancer than men with diabetes. That is in the statistical mud range for epidemiology.

Their credibility is further undermine when co-author Dr. Sanne Peters, of The George Institute for Global Health at the University of Oxford, claims women are subject to an excess risk of cancer because they are in the pre-diabetic state of impaired glucose tolerance two years longer on average than men. Like pre-pregnancy, pre-diabetes does not exist. It is simply a lower a1c level. Fewer than 5 percent of people with the lower a1c level will go on to develop diabetes in their lifetimes, making it clinically irrelevant. 500 million people in China would be on medication for pre-diabetes if that were real.

Despite the flaws, lead author Dr. Toshiaki Ohkuma, research fellow with The George Institute for Global Health, claims, "the link between diabetes and the risk of developing cancer is now firmly established", which will alarm experts in those fields.