Smoking can cause impotence, but few men are aware of these dangers. A new report by the British Medical Association (BMA) and the anti-tobacco group Action on Smoking and Health (ASH) presents a stark contrast to the slick advertising images of rugged, sexy male smokers. The report estimates 120,000 men in Britain are impotent as a direct result of their habit and says a recent MORI poll showed 88 percent of smokers do not know the sexual risks they are taking. Both groups are urging the British government and the European Union to add new warnings on cigarette packets saying smoking causes impotence and can damage sperm.

The damage smoking causes is cumulative. Years of smoking make it difficult for men to achieve or sustain an erection. Teenage smokers who can't kick the habit could be impotent by the time they reach their 30s or 40s. Smoking causes a buildup of fatty deposits in delicate blood vessels. But instead of blocking blood flow to the heart, as in the case of heart disease, it stops the supply to the penis.

Nicotine can also cause rapid contractions in penile tissue or damage a valve mechanism that traps blood in the penis. Research studies have shown that smoking can increase the chances of becoming impotent by 50 percent and can also compound other risk factors for erectile dysfunction.

Hormone abnormalities, high cholesterol levels, diabetes, strokes and kidney and liver problems can cause impotence.

Men with large waistlines are more likely to suffer from erectile dysfunction than those of slimmer girth, according to new data presented at the annual meeting of the American Urological Association.

In a survey of 1,981 men aged 51 to 88, 34 percent reported moderate to severe erectile dysfunction (ED). These men also were more likely to be older, have high blood pressure and to weigh more than their study counterparts. In fact, after adjusting for age, smoking and hypertension, men with a larger waistline were more likely to suffer from ED. Men with a waistline measuring 42 inches were nearly twice as likely to suffer from ED compared with men whose girth measured 32 inches.

The data also showed that men who were inactive were more likely to suffer from ED than men who exercised at least 30 minutes per day.

Erectile dysfunction may be an early warning sign of heart disease, according to research being presented at the American Heart Association Scientific Sessions. Therefore, physicians should determine the cause of a man's erectile dysfunction and recommend additional evaluation in cases where it may be the result of diseased blood vessels, says the researcher.

Erectile dysfunction is defined as an inability to achieve or maintain an erection. "Erectile dysfunction could be called a 'penile stress test,' and may be another way for detecting diseased blood vessels in much the same way that the exercise stress test, which measures electrical signals from the heart, is used to detect diseased blood vessels of the heart," says Dr. Marc R. Pritzker, of the Minneapolis Heart Institute Foundation. "We now understand that atherosclerosis detected in one set of blood vessels markedly increases the chances of having this form of blood vessel disease in other areas of the body including the heart, brain, legs and kidneys. Because the blood vessels that supply the penis are narrower than arteries in other areas of the body, atherosclerosis -- the disease process that leads to heart attacks and strokes -- may manifest itself as erectile dysfunction before the disease becomes apparent in other arteries. This provides a wonderful opportunity for strong preventive programs that could reduce the risk of heart attacks and strokes," Pritzker says.

Penile artery dysfunction caused by high blood pressure and arterial disease is the main cause of impotence in hypertensive men, according to research published in the American Journal of Hypertension.

"Impotency is a major problem, especially in older hypertensive men," said Dr. Michael Weber, an editor of the journal, in a press statement. "Many patients tend to blame the blood pressure medicine itself for causing the impotency, but this new study... indicates that the underlying medical condition of atherosclerosis and the physical effects of blood pressure reduction itself are the primary cause of the problem."

In a study of 101 hypertensive men evaluated at a hypertensive clinic in Denmark, 27 were impotent -- a much higher rate than the 4% impotence rate found in the general population, according to lead investigator Dr. Jesper Jensen of Glostrup University Hospital of Copenhagan, Denmark. 18 of the 27 impotent men were found to have penile arterial dysfunction, which is largely due to atherosclerosis in the penile arteries. Not surprisingly, impotence was related to age, but the prevalence was also "remarkably high (23% to 45%) in middle-aged patients (40 to 69 years of age)," according to the study. The investigators also found that intermittent claudication, or cramping in the calves due to poor circulation, was the one variable with the highest correlation to impotence, followed by ischemic heart disease.

While some patients reported that impotence only became a problem once they started on antihypertensive medication, the researchers report that their results "pointed towards a mechanism related to blood pressure reduction rather than to specific drug side effects" as the cause.

The researchers advise physicians to ask patients taking antihypertensive medication about their sexual functioning. "Frank and open discussions will help physicians determine the cause of impotency and then initiate treatment," said Weber, who is also president of the American Society of Hypertension.