Having a thick neck greatly increases the risk for obstructive sleep apnea. Most people’s necks’ thickness is due to extra “soft tissue,” namely fat. However, it’s been postulated that edema in the soft tissues of the neck may also cause an increase in overnight neck thickness and cause/worsen obstructive sleep apnea. Reports in this month’s Blue Journal and Journal of the American College of Cardiology suggest that volume overload and/or fluid shifts during sleep probably contribute to OSA’s pathogenesis and its severity.
Stefania Redolfi et al recruited 12 people with chronic venous insufficiency and edema of the legs, diagnosed by doppler ultrasound, who also had severe OSA with AHI of 48 on average. There was no attempt to ascertain the presence or absence of congestive heart failure. When these people lied down, the measured volume in the legs fell (~280 mL) and their neck circumferences increased by 1 cm.
After putting leg compression stockings on the patients for one week, these volume shifts were attenuated. Leg volume changed less overnight (by 150 mL), and neck circumference only increased ~0.3 cm instead of 1 cm. Most interestingly, their apnea-hypopnea index fell by 36% as well (still leaving them with an AHI of ~30 though).
In other news, Takatoshi Kasai et al report that among 54 people with CHF referred for polysomnography, those found to have OSA (31 of them) had significantly higher sodium intake (3.0 g vs 1.9 g, by self-reported food diaries) than those without OSA. Sodium intake was an independent predictor of high AHI on multivariate analysis. Authors conclude that sodium intake may contribute to the development of OSA in people with congestive heart failure.
Redolfi S et al. Attenuation of Obstructive Sleep Apnea by Compression Stockings in Subjects with Venous Insufficiency. Am J Respir Crit Care Med 2011;184:1062-1066.
Kasai T et al. Relationship Between Sodium Intake and Sleep Apnea in Patients With Heart Failure. J Am Coll Cardiol 2011;58:1970-1974.