Obstructive Sleep Apnea (OSA)
➤ OSA in obesity arises from upper airway collapse exacerbated by
pharyngeal and central adiposity, with hormonal dysregulation and
OSA-induced intermittent hypoxia perpetuating sympathetic and
renin-angiotensin-aldosterone system activation, thereby promoting
hypertension and metabolic dysfunction.
Risk Factors
• OSA risk is strongly influenced by modif iable factors, such as obesity
(10% weight gain increases risk sixfold), with visceral fat distribution
and waist-to-hip ratio being more reliable predictors than BMI.
Additional modif iable contributors include hypertension, which
shares a bidirectional relationship with OSA (present in 50% to 70%
of those with resistant hypertension), as well as lifestyle factors like
f requent daytime napping, poor health status, low physical activity,
and coexisting metabolic dysfunction, including insulin resistance
and dyslipidemia. Nonmodif iable risk factors include older age,
male sex (women approaching comparable risk after menopause),
craniofacial anatomical features (e.g., retrognathia, macroglossia,
tonsillar hypertrophy), and genetic predisposition, including ethnic
variations that increase OSA risk at lower BMI in some populations.
➤ Clinical Manifestations
• OSA presents with nocturnal symptoms (e.g., loud snoring, witnessed
apneas, gasping) and daytime sequelae (excessive sleepiness,
cognitive impairment). Cardiovascular complications include systemic
hypertension, atrial fibrillation, and HF, driven by hypoxia-induced
oxidative stress and endothelial dysfunction. Metabolic consequences,
such as insulin resistance and elevated triglycerides, are mediated
by adipokine dysregulation (e.g., reduced adiponectin and elevated
ghrelin). Untreated OSA also correlates with a reduced quality of life
and an increased risk of motor vehicle accidents.
➤ Screening
• The American Academy of Sleep Medicine recommends annual
screening for OSA in high-risk groups using the HEARTS mnemonic
(Heart failure, Elevated blood pressure, Atrial f ibrillation, Resistant
hypertension, Type 2 diabetes, Stroke). Validated tools, such as the
STOP-BANG questionnaire (Snoring, Tiredness, Observed apneas,
high Blood pressure, BMI >35 kg/m², Age >50, Neck circumference
>40 cm, male Gender), are preferred for risk stratif ication.
Importantly, OSA is not exclusive to obesity: 44.4% of patients with
OSA have overweight (BMI 25–29.9 kg/m²), and 23.5% have normal
weight (BMI <25 kg/m²). These f indings underscore the importance
of screening based on clinical risk factors, rather than relying solely
on BMI, as craniofacial anatomy, sex, and age can influence OSA
pathogenesis even in patients without obesity.
