Chest
Volume 120, Issue 5, November 2001, Pages 1442-1447
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Clinical Investigations
SLEEP
Gender Differences in the Expression of Sleep-Disordered Breathing: Role of Upper Airway Dimensions

https://doi.org/10.1378/chest.120.5.1442Get rights and content

Study objectives

Obstructive sleep apnea (OSA) is a common disorder that is characterized by repetitive episodes of upper airway narrowing and collapse. Obesity is a major risk factor for OSA. Compared with men, women have greater total body fat and are more obese, and yet the prevalence of OSA is much higher in men. The airway size and compliance and pharyngeal muscle tone are important determinants of upper airway patency during sleep. The discrepancy between greater frequency of obesity and lower prevalence of OSA in women has not been explained and suggests a different pathogenetic mechanism underlying this condition. Most clinical studies in OSA have either combined the sexes or have described results from men only. The object of this study was twofold: (1) to examine the effect of obesity on pharyngeal size in both men and women, and (2) to determine the role of upper airway dimensions in the expression of sleep-disordered breathing (SDB) and its relationship to gender.

Design

Prospective study of subjects referred for evaluation of SDB.

Setting

University-based sleep center.

Subjects

Seventy-eight male patients (mean ± SE age, 49.2 ± 1.5 years) and 52 female patients (mean age, 47.4 ± 1.5 years).

Measurements and results

All subjects underwent in-laboratory polysomnography with measurement of upper airway size using the acoustic reflectance method. Although the two groups were similar in age, the female patients were slightly heavier than the male patients (body mass index [BMI], 36.0 ± 1.7 kg/m2 vs 33.3 ± 0.8 kg/m2, respectively; p < 0.0001). Despite similar clinical presentation of snoring and excessive daytime sleepiness, women had mild OSA (respiratory disturbance index [RDI], 9.2 ± 2.7 events per hour) or increased upper airway resistance syndrome compared with men with more severe OSA (RDI, 28.0 ± 3.5 events per hour; p < 0.0001). In contrast, women had a significantly smaller oropharyngeal junction and pharynx than men (p < 0.02). Upper airway size correlated significantly with the severity of sleep apnea in men only. There was no correlation between BMI and pharyngeal size in either gender.

Conclusions

This study demonstrates that the static properties of upper airway in awake men but not women correlate with the severity of sleep apnea. This suggests inherent structural and functional differences in upper airway during sleep between men and women with more favorable airway mechanics in women.

Section snippets

Subjects

One hundred fifty-two consecutive patients who were referred to the university sleep center for evaluation of SDB were prospectively enrolled in the study. Twenty-two patients were excluded because of diagnoses other than SDB or having prior uvulopalatopharyngoplasty or clinically evident maxillofacial abnormalities in the form of retrognathia or micrognathia.13 Menopausal state was determined by lack of menses for at least 1 year. Subjective excessive daytime sleepiness was assessed using the

Results

The demographic characteristics, RDIs, and arousal indexes of apneic and nonapneic patients are shown in Table 1. There were 78 men (mean age, 49.2 ± 1.5 years) and 52 women (mean age, 47.4 ± 1.5 years; p = 0.30). In the male group, patients with OSA were older than those with increased UARS with no significant difference in body mass index (BMI) or Epworth Sleepiness Scale scores. There was no significant difference in age and BMI between increased UARS and OSA in the female patients. Men had

Discussion

The present study demonstrates a significant gender effect on the upper airway dimensions and expression of sleep-related breathing disorders in a large group of markedly obese male and female subjects. We found that obese female patients presenting with excessive daytime sleepiness and snoring had mild OSA compared with their male counterparts who had severe OSA. In female patients, both OPJ and pharyngeal cross-sectional areas were significantly smaller than male patients for a comparable

Acknowledgment

The author thanks Lauren Pollio and Wendy Stegina for technical assistance and Uyi Osaseri for assistance with data analysis.

References (29)

  • G Pillar et al.

    Airway mechanics and ventilation in response to resistive loading during sleep

    Am J Respir Crit Care Med

    (2000)
  • L Brooks et al.

    Size and mechanical properties of the pharynx in healthy men and women

    Am Rev Respir Dis

    (1992)
  • I Rubinstein et al.

    Lung volume-related changes in the pharyngeal area of obese females with and without obstructive sleep apnoea

    Eur Respir J

    (1989)
  • JB Shellenberg et al.

    Physical findings and the risk of obstructive sleep apnea: the importance of oropharyngeal structures

    Am J Respir Crit Care Med

    (2000)
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