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Risk Factors
• OSA risk is strongly influenced by modifiable 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 modifiable 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
frequent daytime napping, poor health status, low physical activity,
and coexisting metabolic dysfunction, including insulin resistance
and dyslipidemia. Nonmodifiable 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.
Obstructive Sleep Apnea
➤ 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.
➤ 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 f ibrillation, 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.
