Link between smoking and impotence?

I have been a cigarette smoker for twenty years.  Is there scientific evidence that my erectile problems can be traced to my smoking habits?

Many studies have linked smoking and erectile disorder.

For decades, research studies have concluded that men who smoke cigarettes have a significantly higher rate of impotence vs. men who do not smoke.

•  A 2006 study in Australia found that smoking more than 1 pack/day lead to a 40% increase in impotence.
• Current smokers are 40% more likely to have ED compared to non smokers.
• Many scientific reviews have found similar links between impotence and tobacco smoking.

There is overwhelming evidence that tobacco smoking leads to a higher risk of impotence and erection problems.