Abstract
Nocturia, or waking at night to void, is a common problem among both men and
women of all ages. It is regarded as one of the most bothersome urinary symptoms,
which may lead to sleep disturbance. Although the International Continence
Society (ICS) defined nocturia as waking at night to void one or more
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times, only a
nocturnal voiding frequency of two or more seems to generate significant bother
and decreased quality of life. Furthermore, nocturia is associated with an increase
in falls and hip fractures and may even be associated with an increased mortality
rate.
Traditionally, urologists have considered nocturia to be an increased urinary frequency
at night without paying much attention to urine volume, whereas internists
have assumed nocturnal frequency to be the result of an excessive urine production
without focus on other lower urinary tract symptoms. Nowadays, both medical
disciplines agree that the causes of nocturia can roughly be divided into the following
categories: 1) sleep disorders, 2) nocturnal polyuria, 3) 24-hour polyuria, and
4) reduced bladder capacity. Clearly, nocturia is a symptom, rather than a disease.
However, regardless of its cause, nocturia appears when the production of urine is
greater than the storage capacity of the bladder.
Although earlier studies have provided information on possible causes of nocturia,
almost all of these studies were cross-sectional and based their data on selfreport
questionnaires. Because of this, the information concerning which factors
are causally related to nocturia remains unclear.
The Krimpen study was initiated in 1995 to monitor the natural history of lower
urinary tract symptoms (LUTS) in the aging male and its burden on the general
population of older men. A total of four rounds of data collection were performed.
The three follow-up rounds had a planned follow-up time of 2, 4 and 6 years. Data
collection ended in 2004. In addition to the original design, the general practitioner’s
database was checked again after 15 years (2010) for (possible) date of
death. In addition to extensive data on health status, the Krimpen study database
contains data on longitudinal frequency-volume charts (FVC). These FVC data offer
insight into the epidemiology and natural history of both FVC-based nocturia and
nocturnal polyuria.
This thesis describes the natural history of nocturia and of voided volumes, as well
as that of an important contributor to nocturia, i.e. nocturnal polyuria. The association
between nocturia and the mortality rate in older men is also examined. In the
first four chapters an introduction and aims of the study, study design, a review of
the literature and the specific methodology of FVC analysis are presented.
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