BPH becomes more common as men age. The enlargement to the prostate occurs gradually, and may be largely the result of hormonal changes associated with ageing, such as decreases in testosterone, increases in oestrogen, and increased conversion of testosterone to a more potent form called dihydrotestosterone. This causes an overproduction of prostate cells, which in turn causes the prostate to enlarge.
The prostate surrounds the urethra, the tube through which urine flows, and as it enlarges, it obstructs the urethra, interfering with urination and the ability to completely empty the bladder.
Factors that influence male hormonal balance or the muscle tone of the prostate may play a role in BPH. These include eating a high fat diet, blood sugar imbalance, chronic inflammation and free radical activity.
Genetic factors may play a role, especially in cases with early onset.
BPH is more likely to affect men who do little physical activity, and those with abdominal obesity.