We interviewed a population sample of 2412 men aged 40-70 y in Brazil, Italy, Japan and Malaysia about medical history, lifestyle habits and sexual behavior. Men were classified as having moderate or complete erectile dysfunction (ED) if they reported to be sometimes or never able to achieve and maintain an erection satisfactory for sexual intercourse, respectively. There were 1335 men with no diagnosis of cardiovascular or prostate diseases, diabetes, ulcer or depression, nor taking hormones. The prevalence of ED was 16.1%. ED was associated with age (the risk increased 8% per y), moderate (odds ratio (OR)=2.2) or severe (OR=4.9) lower urinary tract symptoms and smoking (OR=2.3 for >30 cigarettes/day). It was inversely associated with physical activity (OR=0.5) and higher educational levels. Between the ages of 40 and 70 y, almost one in six 'healthy' men is affected by ED. Further research should look at preclinical disease stages and genetic factors.
The quest for improving and maintaining sexual function has been going on since time immemorial. The advent of an effective oral drug, sildenafil, has brought about unprecedented open discussion on male erectile dysfunction, and gas accelerated the pace of development of new therapies for erectile dysfunction. New knowledge in the physiology of sexual function has enabled researchers to target drug treatment at the whole network of the central nervous system and the numerous cascadic enzymatic reactions leading to relaxation of the corporal smooth muscle. One of the brightest potential applications of future molecular technology in the study of erectile dysfuction is in the utilization of gene therapy.