Interrelation of erectile dysfunction and lower urinary tract symptoms

Area of Science:

• Urology
• Andrology
• Epidemiology

Background:

• Erectile dysfunction (ED) and lower urinary tract symptoms (LUTS) are highly prevalent conditions in aging men.
• Both ED and LUTS significantly impact patients' quality of life.
• The co-occurrence of ED and LUTS has prompted investigation into a shared underlying pathophysiology.

Purpose of the Study:

• To evaluate the evidence for a causal relationship between ED and LUTS.
• To apply Hill's criteria for causality to the association between ED and LUTS.
• To explore potential pathophysiological mechanisms linking ED and LUTS.

Main Methods:

• Systematic review of epidemiological studies examining the association between ED and LUTS.
• Application of Hill's criteria (e.g., strength of association, consistency, dose-response, biological plausibility) to assess causality.
• Review of proposed pathophysiological theories, including autonomic hyperactivity, nitric oxide pathways, ischemia, and Rho-kinase/endothelin activity.

Main Results:

• Epidemiological studies demonstrate a strong association, internal consistency, and dose-response effects between ED and LUTS.
• Multiple regression analyses in large studies indicate the ED-LUTS relationship remains significant, accounting for alternate explanations.
• Four leading pathophysiological theories (autonomic hyperactivity, altered nitric oxide, ischemia, Rho-kinase/endothelin) provide biological plausibility for the link.

Conclusions:

• While a definitive causal link cannot be established solely on current epidemiological data, most components of Hill's criteria for causality are met.
• The strong association and plausible biological mechanisms suggest a potential causal relationship between ED and LUTS.
• Further research is needed to elucidate the temporal relationship and confirm causality between ED and LUTS.