Effectiveness of Laxatives in the Elderly - NIHR Health Technology ...

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Epidemiology of constipation in the general adult population
4 years from retirement age. Lower caloric intake
in the elderly (adjusted for fibre consumption)
has also been implicated in the aetiology of
constipation (Towers et al, 1994).
Fluid intake
Lack of fluid has been cited as a risk factor for
constipation (Richards-Hall et al, 1995; Maestri-
Banks & Burns, 1996). It has been suggested that
the elderly may drink less in an attempt to control
incontinence (Richards-Hall et al, 1995), thus
increasing the risk of constipation. However, there
have been few studies which have examined the
effects of low fluid intake on constipation while
controlling adequately for other factors. One
such study has shown low fluid intake to be related
to slow colonic transit (Towers et al, 1994), and
another found it to be related to low stool output
in healthy adults (Klauser et al, 1990). Constipated
adults in Sandler and colleagues’ (1990) large US
survey also reported less consumption of beverages
(sweetened, carbonated and non-carbonated)
in constipated adults. However, in a community
survey in New Zealand, no association with
constipation was found (Campbell et al, 1993).
Mobility
Physical mobility problems are more likely in
the elderly, and constipation has been found
to be more prevalent in those who take little
exercise or are relatively inactive (Sandler et al,
1990). This association persisted after controlling
for age. Kinnunen (1991) has calculated that
the risk of constipation is significantly increased
with decreased physical mobility, the highest
risks being associated with being chairbound or
bedbound. Several studies have described bowel
management programmes in institutionalised
patients in which exercise has been recommended
in the treatment of constipation (see, for example,
Karam & Nies, 1994; Kligman & Pepin, 1992). Exercise
has also been recommended in several reviews
(Romero et al, 1996; Lederle, 1995). However, as
Klauser and Müller-Lissner (1993) point out, these
treatments have not been formally evaluated in
constipated patients. This has been confirmed by
a Medline search (1966–96) (see Appendix 1).
Other risk factors
Other variables which have been implicated in
the development of constipation, such as anxiety,
depression and impaired cognitive function, are
also more prevalent in older age groups. Increased
use of constipating drugs may also become important
and anticholinergic anti-depressants, opioid
analgesics and NSAIDs, including, in particular,
aspirin, seem to have a role to play (Monane et al,
1993; Canty, 1994; Jones & Tait, 1995). A more
extensive list of other risk factors for constipation
has been given by Moriarty and Irving (1992).
Finally, Harari and colleagues (1993) systematically
reviewed the pathophysiology, symptoms, diagnosis,
causes and treatment of constipation in older
people and concluded that while the prevalence
of self-reported constipation increased with age,
a similar increase in the prevalence of ‘true
clinical constipation’ is not shown. They also
questioned the validity of many suspected risk
factors. However, the inclusion and exclusion
criteria for the review are unclear and there is
no assessment of the quality of the studies.
A full systematic review of the epidemiology of
constipation appears not to have been carried out
and is beyond the scope of the present study.