title: Normal values and determinants of circadian urine production in older men: a population based study.
abstract: OBJECTIVE
  We evaluated circadian urine production and its determinants in a large population based sample of older men.
  
  
  METHODS
  We collected data on 1,688 men 50 to 78 years old, without radical prostatectomy, prostate or bladder cancer, neurogenic bladder disease or negative advice from their general practitioner, recruited from the population of Krimpen, the Netherlands. Measurements consisted of self-administered questionnaires, including the International Prostate Symptom Score, a 3-day frequency-volume chart, transrectal prostatic ultrasound, uroflowmetry and post-void residual volume. Hourly urine production was determined and urine production day-to-night ratio was calculated from the frequency-volume chart.
  
  
  RESULTS
  Men younger than 65 years showed a clear circadian urine production pattern, whereas in older men this pattern was less clear. Smoking, use of diuretic drugs, post-void residual and 24-hour polyuria reinforced the circadian pattern, in favor of daytime urine production. The urine production day-to-night ratio was not associated with prostate enlargement, reduced urinary flow rate, body weight, hypertension, cardiac symptoms, diabetes mellitus, use of antidepressants, cardiac or hypnotic drugs.
  
  
  CONCLUSIONS
  Urine production in men younger than 65 years showed a clear circadian pattern in contrast to men older than 65 years. These data can be used as a reference when describing urine production patterns in select populations. In daily practice frequency-volume charts can be used to determine urine production. This method is inexpensive, easy to use and provides valid information on urine production in a natural environment.
mesh_terms: D000368:Aged; D000375:Aging / Q000652:urine*; D002940:Circadian Rhythm / Q000502:physiology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D009426:Netherlands; D012016:Reference Values; D014563:Urodynamics / Q000502:physiology*