Men with diabetes who are having trouble keeping an erection could be at increased risk of serious heart problems, suggests a study.
Those with erectile dysfunction were twice as likely as other men with diabetes to develop heart disease.
The root cause of both can be blood vessel damage caused by high blood sugar levels, the Chinese University of Hong Kong said.
Experts said men with erectile dysfunction should see their doctor.
The Journal of the American College of Cardiology reported that researchers wanted to see if erectile dysfunction could be a reliable independent warning signal for doctors that further problems were on the way.
Previous research has suggested that the arrival of the sexual problem generally precedes the development of heart symptoms in type II diabetic men by approximately three years, and the study tested this link in more detail.
A group of 2,306 men were recruited, of which just over a quarter already had erectile dysfunction. None of the men had any obvious signs of heart disease, or stroke.
Over the next four years, 123 men either suffered a heart attack, died from heart disease, developed chest pain linked to clogged arteries, or ended up needing a heart bypass or cardiac catheterisation.
Men with erectile dysfunction were approximately twice as likely to end up in this group compared with those with normal sexual performance.