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Sleep Apnea & Hypertension
Last edited |
10/28/2008
The relationship between Sleep-Disordered Breathing and
Hypertension is a major issue requiring elucidation, especially as appropriate
treatment of the former may help control or even protect against the latter
However, the literature review on this topic raises many
ambiguities:
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with several pathologies and obstructive sleep apnea
syndrome (OSAS), a specific clinical entity associated with a polysomnographic
pattern (apnea/hypopnea index (AHI) >five apneas plus hypopneas per hour of
sleep) and characterized by daytime sleepiness or insomnia but dissociated
from obesity.
This conceptual misunderstanding has prevailed since the 1970s
[Guilleminault et al., 1997; Coccagna
et al., 1972; Guilleminault et al., 1973; Guilleminault et al., 1975].
Recent reviews [Fletcher,
1995; Wright et al., 1997] regarding the association between hypertension and
sleep-disordered breathing failed to make the distinction between OSAS and
multi-morbid syndromes associating obesity and OSA.
Therefore, the
relationship between obstructive sleep apnea syndrome and hypertension remains
poorly defined.
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In addition to this problem of terminology, general
population studies of hypertension and sleep-disordered breathing are rare.
Gislason et al. [1993] explored this association in a representative sample of
the Swedish male population.
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Although other studies may involve large samples,
as was the case with the Wisconsin sleep cohort [Young
et al., 1993] and the Busselton cohort
in Australia [Bearpark et al., 1995], findings were applied to the general population only through
secondary extrapolation which may or may not be valid depending on the initial
population.
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Finally, the identification of confounding variables
may impact the association between sleep-disordered breathing and
hypertension.
Obesity, smoking and alcohol consumption are not always
considered and are often inadequately assessed [Levinson
et al., 1991]. Moreover, life stress,
which may be equally important, has not been included in any study to date.
Consequently, we decided to assess the relationship between
hypertension and three forms of sleep-disordered breathing: namely, chronic
snoring, breathing pauses and OSAS, in the course of telephone surveys
undertaken in the general populations of the UK,
Germany and Italy.
Research
This report presents the results obtained after controlling
for confounding variables:
 Age,
body mass index,
alcohol,
smoking,
life stress,
heart diseases,
renal diseases.
The relationship between hypertension and three forms of sleep-disordered
breathing (chronic snoring, breathing pauses and obstructive sleep apnea
syndrome) was assessed using representative samples of the non-institutionalized
population of the United Kingdom, Germany and Italy (159 millions inhabitants).
The samples were comprised of 13,057 individuals
aged 15-100 years who were interviewed about their sleeping habits and their
sleep symptoms over the telephone using the Sleep-EVAL system.
Results
Obstructive Sleep Apnea Syndrome was found in:
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1.9% (95% CI: 1.2% to
2.3%) of the UK sample,
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1.8% (95% CI: 1.4% to
2.2%) of the German sample and
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1.1% (95% CI: 0.8% to
1.4%) of the Italian sample.
Obstructive Sleep Apnea Syndrome
was an independent risk factor (odds ratio: 9.7) for hypertension after
controlling for possible confounding effects of age, gender, obesity, smoking,
alcohol consumption, life stress, and, heart and renal disease.
Snoring and breathing pauses during sleep appeared to be
non-significant predictive factors.
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Sleep-EVAL
Research
