The Massachusetts Male Aging Study was probably the first study that brought to light how common erectile dysfunction is. This study demonstrated that 52% of men between the ages of 40 and 70 have some degree of erectile dysfunction (Figure Below). Of those individuals, 10% noted complete erectile dysfunction, 25% noted moderate erectile dysfunction, and most noted mild erectile dysfunction.

Prevalence of erectile dysfunction: Massachusetts Male Aging Study, 1987-1989 (n = 1626).

In the United States, approximately 50 million men suffer from erectile dysfunction (impotence). The prevalence (number of cases of a disease that are present at a given point in time) of erectile dysfunction is age dependent, with the rate of complete erectile dysfunction increasing from 5% among men 40 years old to 15% among those 70 years old. As our population continues to grow and age, we can only expect this number to increase. The worldwide prevalence of erectile dysfunction was 152 million in 1995 and is expected to increase to 322 million in 2025. Much of this increase will occur in the developing world and reflects the aging of the world's population.

The incidence (i.e., the number of new cases occurring during a specific period of time) of erectile dysfunction is higher in men with certain diseases, such as diabetes mellitus, hypertension, cardiovascular disease, spinal cord injury, and hypercholesterolemia (high cholesterol levels). Often, the sexual dysfunction of impotence in men is a symptom of another problem. However significant and expensive diagnostic evaluations not always needed, especially for men with chronic impotence. Determining why ED is occurring and identifying the root causes of ED is very important to make a precise diagnosis and provide accurate therapy and treatment.

The potential economic impact of erectile dysfunction is huge. In the 1985 National Ambulatory Medical Care Survey, erectile dysfunction was associated with 525,000 outpatient office visits, and the 1995 National Hospital Discharge Survey reported that it accounted for more than 30,000 hospital admissions. The projected sales of Viagra, the first oral therapy for erectile dysfunction, were estimated at $1.4 billion for 1999. Who should cover the costs of the treatment of erectile dysfunction remains a source of debate.

After the introduction of Viagra the market of ED drugs has boomed and exceeded any expectations. That's why when several years later Levitra and Cialis were introduced to the market they have succeeded quite well, taking their own niches of ED (impotence) medication market with ease. Cialis is now known as the most long-lasting ED pill available, while Levitra helped many of those, who found Viagra ineffective. Besides, Levitra was free from many of side-effects and interactions its predecessor was known for.

With drugs like Cialis and Levitra the market of ED medications has become more diverse, providing more options for treatment. That's why the sales of these drugs and ED drugs in general are on the rise. There are numerous real-world drugstores and online pharmacies selling Cialis and Levitra today, and their number keeps on growing. And it's seen not only in US, as you can buy Cialis or Levitra online just anywhere in the world and say goodbye to ED once and for all.