0 % |
10 % |
20 % |
30 % |
40 % |
Prevalence * |
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Obstructive sleep apnoea
Obstructive sleep apnoea ( OSA ) is a
disorder characterised by repeated episodes of airway closure or narrowing during sleep . It can cause excessive daytime sleepiness , fatigue and cardiovascular sequalae . 21
The apnoea-hypopnea index refers to the average number of apnoea and hypopnoea events occurring per hour of sleep . It is commonly used to classify the severity of OSA into : mild ( 5-15 events / hour ), moderate ( 15-30 events / hour ) and severe ( more than 30 events / hour ). 22
OSA syndrome — that is , experiencing daytime consequences — has a prevalence of approximately 5 %, but estimates of individuals at risk of OSA can be as high as 32 %. 16 Sleep apnoea is more common in men than in women , and is more prevalent in
23 , 24 older adults .
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Figure 2 . Individuals who work night shifts or have irregular sleep schedules are at a higher risk of developing circadian rhythm disorders .
Box 1 . Classification of sleep disorders
• Insomnia .
• Sleep-related breathing disorders .
• Central disorders of hypersomnolence .
• Circadian rhythm sleep-wake disorders .
• Sleep-related movement disorders .
• Parasomnias .
• Other sleep disorders .
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Further complicating the identification of sleep disorders is the overlap between conditions . Some 30-40 % of those with insomnia have comorbid OSA , while 30-50 % of people with OSA meet the criteria for insomnia . 25
Circadian rhythm disorders
Circadian rhythm disorders are a
group of sleep disorders where an individual ’ s internal biological clock is not in sync with the external environment . These disorders affect sleep-wake cycles , causing individuals to struggle with sleeping and
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waking at appropriate times . 26 , 27 An estimated 10 % of the population may experience some form of circadian rhythm disorder , with the most common being delayed sleep phase syndrome ( DSPS ) in younger adults , advanced sleep phase syndrome ( ASPD ) in older adults , and non-24-hour sleep-wake disorder . 18
Individuals who work night shifts ( see figure 2 ) or have irregular sleep schedules are at a higher risk of developing circadian rhythm disorders , with 10-38 % of the shift work population affected
28 , 29
.
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Restless legs syndrome
Restless legs syndrome ( RLS ) is a nocturnal
neurological disorder characterised by an irresistible urge to move and an associated abnormal sensation in the legs . Some patients describe this as a crawling , creeping , aching or itching sensation . 30 These symptoms are worse at rest and can be relieved by movement .
The prevalence of RLS in primary care for those experiencing any symptoms is 11 %, with about 2.4 % of patients reporting that RLS has a significantly negative impact PAGE 30
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