Women with diabetes have a dramatically increased risk of developing cancer, according to a study involving UK researchers.
A global research review involving almost 20 million people has shown that having diabetes significantly raises the risk of developing cancer, and for women the risk is even higher.
“We have demonstrated for the first time that women with diabetes are more likely to develop any form of cancer”
The study authors, from the George Institute for Global Health at the University of Oxford, analysed data from 47 studies from countries including the US, Japan, Australia, China and the UK.
The researchers found that, overall, women faced a 27% increase of developing any form of cancer if they had diabetes, while men also faced a 19% increased risk – a 6% difference.
Specifically, they found diabetes conferred an additional risk for women, compared to men, for leukaemia and cancers of the stomach, mouth and kidney, but less risk for liver cancer.
The risk for women was 15% higher for leukaemia, 14% higher for stomach cancer and 13% higher for oral cancer. Women with diabetes also had an 11% higher risk of developing kidney cancer than men with the condition.
In contrast, for liver cancer, the risk was 12% lower for women with diabetes compared to men with diabetes.
“Historically we know that women are often undertreated when they first present with symptoms of diabetes”
The study authors said: “Diabetes is a risk factor for all-site cancer for both women and men, but the excess risk of cancer associated with diabetes is slightly greater for women than men.”
Their findings were published last month in Diabetologia, the journal of the European Association for the Study of Diabetes.
Lead author Dr Toshiaki Ohkuma, research fellow with the George Institute, said: “The link between diabetes and the risk of developing cancer is now firmly established.
“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 leukaemia,” he said.
He added: “It’s vital that we undertake more research into discovering what is driving this, and for both people with diabetes and the medical community to be aware of the heightened cancer risk for women and men with diabetes.”
The researchers suggested that heightened blood glucose may have cancer-causing effects by leading to DNA damage.
Co-author Dr Sanne Peters noted that women were in the pre-diabetic state of impaired glucose tolerance two years longer on average than men.
“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,” she said.
“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,” said Dr Peters.
“The differences we found are not insignificant and need addressing,” she said. “The more we look into gender specific research the more we are discovering that women are not only undertreated, they also have very different risk factors for a whole host of diseases, including stroke, heart disease and now diabetes.
“This could be a very significant piece of research, and one that could help to save lives”
Based on the findings, the Oral Health Foundation said it was calling on people to be aware of the close links between their oral health and their wider wellbeing.
Charity chief executive Dr Nigel Carter said: “This could be a very significant piece of research, and one that could help to save lives. Diabetes has previously been linked to poor oral health, but this new research shows a specific link to mouth cancer.
“This makes regular dental visits an absolute must,” he said. “For many years we have known that diabetic patients are more likely to get gum disease and need extra dental care but this is yet another reason for regular checks.”
He added: “It is important, not just for diabetics but for everyone to be aware of what the signs and symptoms of mouth cancer are. More people lose their lives to mouth cancer every year in Britain than from cervical and testicular cancer combined.”