Epidemiology of obstructive sleep apnea

Area of Science:

• Sleep Medicine
• Respiratory Physiology
• Epidemiology

Background:

• Sleep-disturbed breathing, encompassing apneas and hypopneas, is prevalent and increases with age.
• Obstructive sleep apnea (OSA) is the most common type, diagnosed via polysomnography.
• Existing prevalence studies suffer from methodological limitations like selection bias and inconsistent definitions.

Purpose of the Study:

• To highlight methodological weaknesses in current sleep-disturbed breathing and OSA prevalence studies.
• To emphasize the need for standardized definitions and rigorous study designs.
• To identify key risk factors and suggest appropriate research methodologies.

Main Methods:

• Review of existing literature on sleep-disturbed breathing and OSA prevalence.
• Critique of methodological flaws in prior studies (e.g., sampling, definitions, confounding variables).
• Recommendation for two-stage sampling, polysomnography for symptomatic individuals, and exclusion of comorbidities.

Main Results:

• Prevalence studies often lack rigor, leading to uncertain estimates of OSA.
• The diagnostic cutoff of 5 events/hour lacks clear origin and may not correlate with reduced longevity, especially in asymptomatic individuals.
• Age, upper airway abnormalities, alcohol, and family history are established risk factors; endocrine factors require further investigation.

Conclusions:

• There is a need for improved methodologies in OSA prevalence research.
• Distinguishing symptomatic from asymptomatic individuals is crucial for accurate diagnosis and risk assessment.
• Further case-control studies are recommended to investigate potential endocrine risk factors for OSA.