People with diabetes are at greater risk of developing and dying from cancer, according to new research.
The findings emerged from two separate studies presented at this year’s European Association for the Study of Diabetes annual meeting.
“It seems likely that factors associated with obesity and diabetes contribute differentially to specific cancer types”
Both pieces of research (see attached PDFs of posters below) suggest people with diabetes are at greater risk from cancer, compared to those without diabetes.
A UK study by the University of Manchester found people with type 2 diabetes were at greater risk of dying from cancer – especially when it came to obesity-related cancers such as bowel, kidney and pancreatic cancer or breast and endometrial cancer in women.
However, the study, which looked at data on nearly 177,000 adults with type 2 diabetes also suggested diabetics were at greater risk of dying from non-obesity related cancers.
Researchers compared data on 176,886 people with type 2 diabetes from the UK Practice Research Datalink with a matched control group of nearly 853,000 people without diabetes.
The study, which looked at 13 types of cancer, suggested men with type 2 diabetes were 22% more likely to die from any cancer than those without diabetes. For women the risk was 31% higher.
Both men and women with diabetes were considerably more likely to die from obesity-related cancers than their diabetes-free counterparts – 84% and 47% higher, respectively.
“It’s also important for health professionals and the public to be aware of the link between diabetes and cancer”
Hulda Hrund Bjornsdottir
Somewhat unexpectedly, they were also more likely to die from non obesity-related cancers, with men facing a 6% higher risk and women an 18% higher risk.
In addition, the research team looked at the link between body mass index and cancer mortality among a sample of more than 145,000 people with type 2 diabetes.
They found a high BMI increased the risk of dying from some specific obesity-related cancers. This link was especially strong for endometrial cancer, with obese diabetics more than four times likely to die from the disease than those with a healthy weight.
“Our findings support the idea that obesity-related mechanisms contribute to the heightened risk of dying from cancer in people with type 2 diabetes,” said study co-author Nasra Alam.
“However, the higher risk for non-obesity related cancers also suggests that other pathways are involved. It seems likely that factors associated with obesity and diabetes contribute differentially to specific cancer types,” Ms Alam.
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Meanwhile, a large-scale study by researchers from Sweden, Iceland and the UK, also found people with type 2 diabetes were at higher risk of developing a number of cancers from the most common types to rarer forms.
The study compared data on more than 450,000 people with type 2 diabetes with more than two million matched controls.
It found individuals with diabetes faced a 20% greater risk of developing colorectal cancer and a 5% higher risk of breast cancer than those without diabetes.
Those diagnosed with cancer fared far worse than peers without diabetes, with a 25% higher chance of dying of colorectal cancer and a 29% higher chance of dying from breast cancer.
In all, diabetes was linked to 11 out of the 12 specific types of cancer investigated in the study.
The condition was clearly linked to higher risk of cancer of the liver with diabetics 231% more likely to be diagnosed.
Individuals with diabetes were 119% more likely to develop cancer of the pancreas, with a significantly heightened risk cancers of the uterus, penis, kidney, gallbladder and bile ducts and stomach.
There was evidence people with diabetes had a reduced risk of prostate cancer compared to those without diabetes, but mortality rates from prostate cancer and colon cancer were higher. Nevertheless, the study authors were keen to stress the absolute risk of cancer was still low.
“Our findings do not suggest that everyone who has diabetes will go on to develop cancer in later life,” said Hulda Hrund Bjornsdottir from the Swedish National Diabetes Register, who led the study.
The findings also suggest that cancers of the pancreas and lung are a growing problem in people with type 2 diabetes, said the researchers
Over a 10-year period, they noted a 38% greater increase in new cases of pancreatic cancer among diabetics, compared to non-diabetics, and a 30% greater increase in lung cancer incidence.
For most other cancer types, rates remained similar in people with and without diabetes over the study period.
“With diabetes being associated with an increased cancer risk and mortality the importance of a healthy lifestyle is clearer than ever,” said Ms Bjornsdottir.
“It’s also important for health professionals and the public to be aware of the link between diabetes and cancer,” she added.