DRUGS given to men to ease the symptoms of prostate disease could make them more likely to develop type 2 diabetes, according to a new study.

However, researchers say patients should continue to take the medicines, which are commonly prescribed to older men, but warn they may need additional health checks.

A team led by the University of Edinburgh and University College London (UCL) stressed that the current guidelines for treatment do not need to change – a finding based on their study of patient health records.

Men with enlarged prostates are commonly prescribed drugs called 5-alpha-reductase inhibitors which reduce the production of hormones called androgens. These help treat symptoms such as reduced urinary flow.

Previous short-term studies had suggested these drugs, which include finasteride and dutasteride, might affect metabolism and could reduce the body’s response to insulin, an early sign of type 2 diabetes.

The team studied health records from around 55,000 men in the UK, who had been prescribed the inhibitors over an 11-year period, and found a link to an increase in risk of about a third of developing type 2 diabetes.

This means that a population of 500 men on this treatment for 20 years would likely expect 16 extra cases of diabetes to develop. A similar result was seen when the team repeated the study with health records from a group of Taiwanese men.

Their findings – published in the British Medical Journal – suggest men taking these medications may need additional health checks to monitor warning signs of diabetes so their prescriptions can be altered if necessary.

Professor Ruth Andrew, of the British Heart Foundation Centre for Cardiovascular Science at the University of Edinburgh, and senior author of the study, said: “These findings will be particularly important for health screening in older men who are already typically at a higher risk of type 2 diabetes.

“We will now continue our studies to better understand the long-term outcomes so we can better identify patients at greater risk.”