Primary Causes of Benign Prostatic Hyperplasia (BPH)
Benign Prostatic Hyperplasia (BPH) is a multifactorial process with an exact etiology that remains unknown, but it fundamentally requires testosterone and is influenced by aging as the primary risk factors. 1
Key Pathophysiological Mechanisms
Hormonal Factors: The conversion of testosterone to dihydrotestosterone (DHT) by 5α-reductase enzymes is essential for BPH development. DHT has a higher affinity for androgen receptors than testosterone and is considered the more potent androgenic steroid hormone that drives prostate growth 1, 2
Cellular Imbalance: BPH develops due to an imbalance between cellular growth and apoptosis (cellular death) in favor of growth, resulting in increased cellular mass in the prostatic transition zone 1, 2
Aging Process: BPH prevalence increases dramatically with age, starting at age 40-45 years, reaching 60% by age 60, and 80% by age 80 1, 2
Anatomical and Functional Changes
BPH leads to benign prostatic enlargement (BPE), which can cause obstruction at the level of the bladder neck, termed benign prostatic obstruction (BPO) 1
BPH contributes to lower urinary tract symptoms (LUTS) via two primary mechanisms:
Risk Factors
Non-Modifiable Risk Factors
Age: The most significant risk factor, with prevalence increasing dramatically after age 40 1, 2
Hormonal Environment: Requirement for testosterone and its conversion to DHT 1, 4
Modifiable Risk Factors
- Metabolic Disease and Obesity: These have been associated with increased incidence of BPH in recent years 5
Disease Progression
The prevalence of moderate-to-severe LUTS rises to nearly 50% by age 80 1
Risk of complications increases with age, including acute urinary retention (AUR) with an incidence of 6.8 episodes per 1,000 patient years overall, increasing to 34.7 episodes in men aged 70 and older 1
Nearly 90% of men between 45 and 80 years of age experience some type of LUTS 1
Cellular and Molecular Mechanisms
The T/DHT-androgen receptor complex within prostate cell nuclei initiates transcription of DNA and translation, leading to prostate growth and hyperplasia 1
Local para- and luminocrine pleiotropic mechanisms and factors are implicated in the prostatic tissue-remodeling process 6
Prostate tissue remodeling in the transition zone involves multiple cellular changes including hypertrophic basal cells, altered secretions, inflammation, increased oxidative stress, and growth factor production 6
Clinical Implications
BPH is nearly ubiquitous in aging males and can significantly impact quality of life through associated LUTS 1
Understanding the causes of BPH is essential for developing effective treatment strategies, including medical therapies that target the hormonal (5ARIs) and dynamic (alpha blockers) components of BPH 1, 7