Clinical, Anthropometric and Upper Airway Anatomic Characteristics of Obese Patients with Obstructive Sleep Apnea Syndrome

Abstract

Background: Obese subjects are at increased risk of developing obstructive sleep apnea syndrome (OSAS). However, the individual role of local (i.e., upper airway-related) and general (clinical and whole-body anthropometric) characteristics in determining OSAS in obese patients is still controversial. Objectives: To contrast the clinical, anthropometric and upper airway anatomical features of obese subjects presenting or not presenting with OSAS. Methods: Thirty-seven obese (BMI ≧30 kg/m²) males with OSAS and 14 age- and gender-matched obese controls underwent clinical and anthropometric (BMI, waist-to-hip ratio and neck circumference) evaluation. In a subgroup of subjects (18 and 11 subjects, respectively), magnetic resonance imaging (MRI) during wakefulness was used to study the upper airway anatomy. Results: OSAS patients showed significantly higher BMI, waist-to-hip ratio and neck circumference as compared to controls (p < 0.05). They also referred to nonrepairing sleep, impaired attention, and previous car accidents more frequently (p < 0.05). The transversal diameter of the airways (TDAW) at the retroglossal level by MRI was found to be an independent predictor of the presence and severity of OSAS (p < 0.05). Parapharyngeal fat increase, however, was not related to OSAS. A TDAW >12 mm was especially useful to rule out severe OSAS (apnea-hypopnea index >30, negative predictive value = 88.9%, likelihood ratio for a negative test result = 0.19). Conclusions: MRI of the upper airway can be used in association with clinical and anthropometric data to identify obese males at increased risk of OSAS.

Sonolência e apnéia do sono: uma parceria desastrosa

“…(2) A recent study involving magnetic resonance imaging of the upper airways to evaluate obese individuals with and without OSAHS showed that, in isolation, greater deposition of fat at this anatomical level is not a determining factor for the development of OSAHS. (8) Of special note is the fact that the excessive daytime sleepiness caused by OSAHS is correlated with traffic accidents, as is well documented in the Knorst et al study appearing in this issue. We pulmonologists are increasingly called upon to manage quality-of-life issues, whether through monitoring environmental pollution, attempting to improve aerobic performance, encouraging smoking cessation, or promoting workplace sanitation, and, by extension, reducing the damage and insults that such factors cause in the lives of our patients.…”

What can anthropometric measurements tell us about obstructive sleep apnoea?

“…However, some studies have demonstrated that the relation between BMI and OSA is unclear. BMI is the traditional marker for obesity, but there has been disagreement about whether it is risk factor for OSA [6,14,17,20]. BMI was increased especially in females with OSA, but it was not correlated with AHI in polysomnography [17].…”

Cervical CT derived neck fat tissue distribution differences in Japanese males and females and its effect on retroglossal and retropalatal airway volume

“…On the other hand, in a group of 18 OSAS with higher BMI and larger neck circumference than the 11 controls included in the study, Hora et al found in awake patients using MRI that the transversal (lateral) dimension of the airway at the retroglossal level was an independent predictor of OSAs, and this lateral narrowing of the airway was not associated with increased fat pad thickness. 11 The authors conclude that the narrowing of the lateral airway is due to parapharyngeal muscular hypertrophy not the accumulation of fat. This conclusion agrees with the findings of Ciscar et al, who found in obese subjects that the parapharyngeal fat increase was not related to OSAS.…”