Testosterone and dihydrotestosterone are the sole causes of the hyperplasia taking place in the prostate after the age of 40 years.

Dihydrotestosterone is considered the more potent of the androgenic steroid hormones by a factor of approximately 10:1.

Only testosterone produced in the testis and not in the adrenal gland enters into the prostate gland.

Of the two 5α-reductase isoforms, type 1 is most commonly found in the prostate.

The volume of androgen receptors in the prostate decreases with aging, leading to a lesser response to androgenic stimuli.

Any man who underwent TURP should alert his sons that their chance of having to have TURP is three times greater than age-matched controls.

The most likely inheritance pattern is autosomal recessive.

There is no evidence that BPH is a familial disease.

Approximately 50% of cases of BPH in men who undergo surgery when younger than the age of 60 are estimated to be inheritable.

Cases of familial BPH tend to occur in men with smaller prostates than the sporadic cases of BPH.

cumulative cases of a disease over a specified time period.

deaths per 100,000 population per year.

existing cases per 100,000 population at a distinct target date.

deaths per number of diseased.

diseased people per 100,000 population per year.

international comparisons are impossible owing to a lack of its definition.

it is commonly found in men of all ages.

it is very uncommon in men younger than the age of 30 years.

it is found in 100% of men beginning at the age of 40 years.

no adequate studies have been done to date.

The IPSS score has been translated and validated in many languages.

The IPSS score addresses irritative and obstructive symptoms and issues of incontinence.

Moderate symptom severity is defined as a score from 10 to 20 points.

Physicians and nurses may fill out the IPSS score for their patients after consultation.

Quantitative symptom scores in BPH are not as important as are objective measures such as a flow rate recording.

International studies show significant similarity in prostate volume in white, age-stratified men.

Magnetic resonance imaging measurements are, in general, smaller compared with transrectal ultrasound measurements.

Although there is a steady increase in total prostate volume with age, the transition zone volume increases only marginally.

DRE estimation of prostate volume is fairly accurate when done by an experienced urologist.

Prostate volume assessment by digital rectal examination (DRE) is reproducible across examiners.

Ethanol consumption increases circulating levels of estrogens.

Most autopsy studies find a higher prevalence of BPH in men with liver cirrhosis.

The intake of ethanol can decrease serum testosterone levels by a variety of mechanisms.

In men with liver disease histologic specimens of the prostate show a similar influence of estrogen such as seen in hormonally treated prostate cancer.

The risk of having surgery for BPH is increased in heavy drinkers.

Calcium channel blockers and β-adrenergic blockers reduce urinary flow rates significantly.

Antihistamines and bronchodilators significantly decrease urinary flow rates.

Anticholinergic agents decrease the peak urinary flow rate markedly.

Antidepressants, antihistamines, and bronchodilators increase the symptom score by several points.

There is no documented influence of any medication on symptoms or flow rate.

Serum PSA level shows a strong correlation with symptom frequency and bother.

Urinary flow rate and prostate volume correlate highly with serum PSA level.

Many studies have shown a significant correlation between the transition zone volume and symptom severity.

A clinically useful correlation exists between prostate volume and serum prostate antigen (PSA) level.

Correlation of symptoms, bother, interference, and quality of life are poor.

Placebo groups have fewer selection biases compared with population-based studies.

Placebo groups from treatment trials are useful because they do not have treatment biases.

No such studies have been conducted.

Control groups from intervention or medical therapy trials reflect the natural history of the disease in unselected community-dwelling men.

A longitudinal population-based study has the fewest biases and is the most useful type of study.

There are convincing data to demonstrate that the final score after treatment is more important than the baseline score or the drop from baseline.

The higher the baseline score, the more of a drop is required for patients to subjectively feel improved.

Placebo response is not dependent on the baseline severity score.

Perception of improvement is independent of baseline score.

Most patients report subjective improvement when the drop from baseline is 30%.

incidence rates of approximately 10/1000 man-years have been reported in all watchful waiting studies.

incidence rates of AUR have not been reported in the urologic literature, only prevalence rates.

the incidence rates reported do not differ significantly between various studies and populations.

depending on the population studied, incidence rates less than 5 to more than 130 cases/1000 man-years have been reported.

AUR has been poorly defined, and therefore no incidence rate can be calculated.

Serum PSA level and prostate volume have limited ability to predict episodes of AUR.

There is virtually no relationship between symptom frequency and bother and AUR episodes.

Urinary flow rates in placebo control groups are strong predictors of AUR episodes.

Serum PSA level is a more powerful predictor of AUR than is age.

Age has been found to be the most significant risk factor for AUR in population-based studies.

Compared with AUR, surgery is a less traumatic end point.

Surgery is a less common end point compared with AUR.

Surgery rates for BPH have remained stable since about 1990.

The incidence rates of surgery are similar across wide geographic regions and ethnic backgrounds.

Most patients with BPH eventually require surgery for their condition.