Researchers examined 6,739 patients aged 52-79. In total, 9.1 per cent of the participants had diabetes. In 22 per cent of men, the condition was previously undiagnosed. For women, only 12 per cent of cases were previously unrecognised.
Simon O'Neill, head of care, information and advocacy at Diabetes UK, said men are generally worse at looking after their health than women.
'We already know that middle-aged men are twice as likely to have diabetes as women and that more men are overweight than women, and so at greater risk of type-2 diabetes,' he said. 'This suggests this pattern is the same for men over 50 who don't realise they have diabetes.'