People with diabetes already have a growing list of complications and concerns they face each day, including that they’re at risk for developing conditions such as retinopathy in their eyes, as well as neuropathy in their fingers and toes.
Now, a recent study has brought more attention to an even more worrisome issue for people with diabetes: cancer.
Researchers from The George Institute for Global Health said they looked closely at almost 20 million people across the globe and concluded that people living with type 1 and type 2 diabetes have a significantly higher incidence of cancer.
They said women with diabetes are at even greater risk with a 27 percent higher likelihood of cancer than women without diabetes.
A man with diabetes has a 19 percent higher risk.
“The link between diabetes and the risk of developing cancer is now firmly established,” explained Toshiaki Ohkuma, PhD, the lead author of the study and a research fellow with The George Institute for Global Health. “We have also demonstrated for the first time that women with diabetes are more likely to develop any form of cancer, and have a significantly higher chance of developing kidney, oral, and stomach cancers, and leukemia.”
This isn’t the first time that cancer risk from diabetes has been studied.
From 2008 to 2012, researchers from the Baker IDI Heart and Diabetes Institute in Australia studied people specifically with type 1 diabetes living in Australia, Denmark, Finland, Scotland, and Sweden.
The results showed a 25 to 50 percent increase in the incidence of cancer in the stomach, liver, pancreas, kidney, and endometrium.
The researchers also pinpointed that while men with type 1 diabetes had a lower incidence of prostate cancer compared to men without diabetes, they were twice as likely to develop liver cancer.
Again, women with type 1 diabetes fared even worse with a 78 percent higher incidence of liver cancer.
What’s the link?
The answer to why people with diabetes are more likely to develop cancer isn’t exactly clear, but there are several theories.
The first posed by the study’s researchers is that elevated blood glucose levels can “damage DNA,” a development that is a known cause of cancer.
Another theory posed by Sarah Wild, PhD, a co-author of the 2008 cancer study, was that long-term treatment using today’s manufactured insulin could potentially be a culprit. A person with type 1 diabetes will die without the treatment.
Another theory proposes that the environment within the body of some people with diabetes is ideal for cancer growth.
“Obesity is also playing an important role here in those with type 2 diabetes,” Dr. Minisha Sood, an endocrinologist at Lenox Hill Hospital in New York City, told Healthline. “Both obesity and type 2 diabetes are associated with metabolic abnormalities that may promote cancer progression.”
Sood added that the overall existing inflammation in people with any type of diabetes is a significant contributing factor.
“This inflammation can lead to insulin resistance within other bodily tissues, and thus leads to higher insulin levels and higher insulin needs,” explains Sood.
“Higher insulin levels may then lead to an increase in other hormones which can promote cell growth and cancer growth as well. Altogether, it is likely a combination of the high blood glucose levels, high insulin levels, higher insulin-like growth factor 1 (IGF1) action, and the known inflammatory environment in patients with diabetes and obesity which leads to increased growth of cancer cells.”
Why are women at greater risk?
What’s still not fully understood is why the overarching risk seems to be so much higher in women.
According to Sanne Peters, PhD, a study co-author and a research fellow in epidemiology at The George Institute for Global Health at the University of Oxford, one theory was a noticeable pattern that women experience prediabetes for nearly two years longer than men before receiving adequate treatment.
“Historically we know that women are often undertreated when they first present with symptoms of diabetes, are less likely to receive intensive care, and are not taking the same levels of medications as men,” Peters said in a statement. “All of these could go some way into explaining why women are at greater risk of developing cancer. But, without more research we can’t be certain.”
Peters added that it’s also well-established that the risk factors for women vary greatly for other conditions such as heart disease and stroke.
Regardless of gender, there’s no arguing that the more diligent a person with any type of diabetes is with eating a diet consisting of mostly whole foods, getting plenty of exercise, monitoring blood glucose levels daily, adjusting medications with the support of their healthcare team, and maintaining a healthy weight will reduce their risk of cancer.