Inoue M, Iwasaki M, Otani T, Sasazuki S, Noda M, Tsugane S. "Diabetes Mellitus and the Risk of Cancer: Results From a Large-Scale Population-Based Cohort Study in Japan." Archives of Internal Medicine, September 25, 2006; 166:1871-1877. http://archinte.ama-assn.org/cgi/content/abstract/166/17/1871?etoc
Researchers from the Japan Public Health Center-Based Prospective Study Group published a report in the Archives of Internal Medicine today which showed a link between diabetes and the risk of total cancer, and in particular several forms of cancer specific to abdominal sites.
The study group included a total of 97,771 Japanese adults (46,548 men and 51,223 women) aged 40 to 69 years who responded to a baseline questionnaire between January 1990 and December 1994. All participants were followed up for cancer incidence through December 31, 2003. At baseline, 6.7% of the men and 3.1% of the women had a history of diabetes.
A total of 6462 cases of newly diagnosed cancer were recorded over the course of the study. Overall, a history of diabetes was associated with a 27% increase in cancer incidence for men and a 21% increase in cancer incidence for women. Cancers of the liver, pancreas, kidney, and ovaries were most strongly associated with diabetes; colon cancer and stomach cancer were also associated but less strongly.
Total cancer incidence in men was 3,907 cases, with 366 cases in men with diabetes. The hazard ratio (HR) for cancer incidence for men with diabetes was 1.27. The HR was especially high for liver cancer (312 cases total, 52 in men with diabetes, HR = 2.24), pancreatic cancer (118 cases total, 16 in men with diabetes, HR = 1.85), and kidney cancer (99 cases total, 13 in men with diabetes, HR = 1.92). Also raised for men with diabetes was the risk of colon cancer (491 cases total, 46 in men with diabetes, HR =1.36) and stomach cancer (977 cases total, 87 in men with diabetes, HR = 1.23).
Total cancer incidence in women was 2,555 cases, with 104 cases in women with diabetes. The hazard ratio (HR) for cancer incidence for women with diabetes was 1.21, lower than for men, and only borderline statistically significant. The HR was higher for ovarian cancer (74 cases total, 5 in women with diabetes, HR = 2.24) and liver cancer (120 cases total, 10 in women with diabetes, HR = 1.94), and was also increased for stomach cancer (362 cases total, 20 in women with diabetes, HR = 1.61).
Unfortunately, there's not enough data to show which direction the causal link between diabetes and cancer runs, if there is one. It may be that the two diseases are linked only indirectly, for example through a mutual source in hereditary or environmental factors. Nonetheless, these study results are interesting and we would like to see further studies done to elucidate the link between diabetes and cancers in the abdominal area.