Type 2 Diabetes May Increase Risk of Certain Cancer Types

People with type 2 diabetes, especially women, are at an increased risk of several different cancer types, according to study findings published in the Journal of Diabetes.

“Diabetes is one of the major public health problems worldwide, with a prevalence of 8.5% (422 million) among the adult population in 2014,” the researchers wrote. “The possible association between diabetes and cancer risk has long been speculated. However, previously reported findings have not been consistent.”

Therefore, researchers in China examined more than 410,000 adults with type 2 diabetes, who had no history of cancer, from July 2013 to December 2016 using the Shanghai Hospital Link database — this included 60 general and specialized hospitals. The median age of patients at the start of the study was 61.8 years. The researchers followed patients for the development of cancer until December 2017.

Through the study, researchers identified 8,485 cases of newly diagnosed cancer — men were at an elevated risk for 11 cancers and women for 13.

In men, prostate cancer was most common. Type 2 diabetes was linked with an 86% higher risk for this type of disease. Additional cancers included colorectal, kidney, liver, lung, pancreatic, skin, stomach and thyroid cancer, as well as leukemia and lymphoma. Men had a significant decreased risk for esophageal cancer and there was no significant change in the risk of nasopharyngeal, small intestine, gallbladder, laryngeal, bladder and other male genital cancers.

Women with type 2 diabetes had a greater than two-fold higher risk for nasopharyngeal cancer, which is a rare type of cancer that affects the part of the throat connecting the back of the nose to the back of the mouth. They were also at risk for breast, cervical, colorectal, esophageal, liver, lung, pancreatic, stomach, thyroid and uterine cancers, as well as leukemia and lymphoma. However, there was a significant decreased risk for gallbladder cancer and no significant change in the risk of small intestine, laryngeal, skin, kidney, bladder, ovarian and other female genital cancers.

Overall, women with type 2 diabetes had a 62% higher risk of developing cancer than the general population, and men a 34% higher risk, according to study findings.

“There was a difference in the magnitude of cancer risk between males and females,” the researchers wrote. “In the present study, the risk of esophageal cancer was decreased in males but increased in females. There may be differences in etiology according to sex and changes in sex hormone levels that affect the progression of cancer at several sites in patients with type 2 diabetes.”

Researchers attributed the large patient population size, high cancer case numbers and the use of medical records rather than self-reported data as strengths of the study.

“These findings have the crucial implication that establishing strategies for cancer-specific regular screening and prevention care among patients with type 2 diabetes are necessary in clinical practice,” the researchers wrote.