Having diabetes drastically increases the risk of developing cancer, especially for women, according to a new global review of studies involving 20 million people, by The George Institute of Global Health.

Published in Diabetologia, the review found type 1 and type 2 diabetes made women 27% more likely to develop cancer than women without the condition. Men with a form of diabetes were 19% more likely to develop cancer than men without. Women with diabetes were also slightly more likely to develop any form of cancer than men with diabetes.

“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,” says lead author Dr. Toshiaki Ohkuma.

The researchers posit that higher levels of blood glucose may damage DNA and thus contribute to cancer. As for why diabetic women are more at-risk of developing cancer, explains co-author Dr. Sanne Peters, the reasons could be many. One possible factor is that women, before being diagnosed as diabetic, experience the pre-diabetic condition of impaired glucose intolerance for 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. All of these could go some way into explaining why women are at greater risk of developing cancer,” says Peters. “But, without more research we can’t be certain.”

In the past 30 years, the number of diabetes cases globally has doubled. In India, roughly one in 20 adults have diabetes, a number that is only expected to grow. It’s part of an imminent non-communicable disease burden “like never before,” according to The Lancet. Yet, the most recent budget included almost 20% less than what the health ministry said was necessary to fund the National Health Mission for the next three years. “Faced with the lower funding, the health ministry has reduced its three-year allocation to tackle NCDs such as cancer and diabetes to $1.4 billion, close to half of the estimated need of $2.4 billion,” The Wire reported in November last year.