Erectile dysfunction -- also called "ED" or impotence -- is the inability to achieve or sustain an erection on repeated occasions. It's estimated that about two of every 100 American men have erectile dysfunction serious enough to warrant a doctor's visit, according to the U.S. National Institute of Diabetes and Digestive and Kidney Disorders. As men age, the risk of erectile dysfunction increases. A recent study of more than 8,000 Australian men between the ages of 16 and 59 found that those who smoked less than a pack a day had a 24 percent increased risk of erectile problems. And, as the number of cigarettes smoked went up, so, too, did the chances of erectile dysfunction. Those men who averaged more than 20 cigarettes a day increased their risk of erectile dysfunction by 39 percent, reported the study, published in the journal Tobacco Control. Another study, this one published in the American Journal of Epidemiology, found that male smokers in their 40s were more likely to experience erectile difficulties than older nonsmoking males. The risk of erectile dysfunction was nearly doubled for smoking men in their 40s compared to nonsmokers in their 50s. Read more at : http://news.yahoo.com/s/hsn/20071231/hl_hsn/menwhosmokepronetoimpotence