Causes
Hormones
Most experts consider androgens (testosterone and related hormones) to play a permissive role in the development of BPH. This means that androgens must be present for BPH to occur, but do not necessarily directly cause the condition. This is supported by evidence suggesting that castrated boys do not develop BPH when they age. In an unusual study of 26 eunuchs from the palace of the Qing dynasty still living in Beijing in 1960, the prostate could not be felt in 81% of the studied eunuchs. The average time since castration was 54 years (range, 41–65 years). On the other hand, some studies suggest that administering exogenous testosterone is not associated with a significant increase in the risk of BPH symptoms, so the role of testosterone in prostate cancer and BPH is still unclear. Further randomized controlled trials with more participants are needed to quantify any risk of giving exogenous testosterone.Dihydrotestosterone (DHT), a metabolite of testosterone, is a critical mediator of prostatic growth. DHT is synthesized in the prostate from circulating testosterone by the action of the enzyme 5α-reductase, type 2. DHT can act in an autocrine fashion on the stromal cells or in paracrine fashion by diffusing into nearby epithelial cells. In both of these cell types, DHT binds to nuclear androgen receptors and signals the transcription of growth factors that are mitogenic to the epithelial and stromal cells. DHT is ten times more potent than testosterone because it dissociates from the androgen receptor more slowly.
Temporary implantable nitinol device (TIND and iTIND): is a device that is placed in the urethra that, when released, is expanded, reshaping the urethra and the bladder neck. Alternative medicine
While herbal remedies are commonly used, a 2016 review found the herbs studied to be no better than placebos. Particularly, several systematic reviews found that saw palmetto extract, while one of the most commonly used, is no better than a placebo both in symptom relief and in decreasing prostate size. Other herbal medicines somewhat effective at improving urine flow include beta-sitosterol from Hypoxis rooperi (African star grass), pygeum (extracted from the bark of Prunus africana), pumpkin seeds (Cucurbita pepo), and stinging nettle (Urtica dioica) root. A systematic review of Chinese herbal medicines found that Chinese herbal medicine, both alone and together with Western medicine, was similar to either placebos or Western medicine in the treatment of BPH. Chinese herbal medicine was found to be superior to Western medicine in improving the quality of life and in reducing prostate volume. Epidemiology
Globally, benign prostatic hyperplasia affects about 210 million males as of 2010 (6% of the population).The prostate gets larger in most men as they get older. For a symptom-free man of 46 years, the risk of developing BPH over the next 30 years is 45%. Incidence rates increase from 3 cases per 1000 man-years at age 45–49 years, to 38 cases per 1000 man-years by the age of 75–79 years.