If you have hypertension, smoking will make it even worse

Dr Ian Banks, BMA

Smoking is also known to accelerate atherosclerosis or hardening of the arteries and when the blood vessels in the pelvis area are narrowed, this contributes to reduced penile blood flow.

It can also lead to narrowing of the arteries in the penis.

Dr Spangler said: "A smoking history should be obtained from all patients, especially those who report erectile dysfunction.

"Informing men about the exceptionally high likelihood of developing erectile dysfunction should become a standard part of care of these patients."

Blood pressure is one of the major causes of erectile dysfunction and some of the treatments for hypertension are also known to increase the risk of impotence.

'Give up'

British Medical Association (BMA) spoksesman on men's health Dr Ian Banks said: "This study confirms what we knew already, but adds another dimension.

"If you have hypertension, smoking will make it even worse.

"The message is to give up smoking."

About 100,000 men in their 30s and 40s in the UK have smoking-related impotence, according to Dr Godfrey Fowler, from Oxford University's Primary Health department .

He said: "Rather few men seem to be aware of the risks and problems."

The US study is being hailed as the first to quantify a 26-fold increase in erectile dysfunction among primary care men whith hypertension who also currently smoke.