Primary Predictors of OSAS Differ in Men and Women

All too often the public is misguided in believing that men are the perpetuators of primary snoring and the overwhelming sufferers of obstructive sleep apnea syndrome, the serious medical condition characterized by episodes of airflow cessation, sleep disturbance and oxygen desaturation due to obstruction in the upper airway.

This is not the case. However, the annual physical conducted by the family physician or internist usually includes a cursory examination of features in the upper airway such as the size of the tongue, tonsils, uvula, soft palate and lateral pharyngeal walls. These, together with obesity, are thought to play crucial roles in the pathogenesis of sleep apnea. A new research study from Sweden now provides evidence that men and women differ in their physiological predictors of sleep apnea, suggesting that the physicial examination for this disorder should incorporate gender differences.

The purpose of this study was, based on patients consecutively referred for evaluation of suspected SAS, to identify predictive characteristics that could easily be assessed during an ordinary clinical examination. The authors of "Predictors of Sleep Apnea Syndrome in Men and Women" are Johanna Dahlqvis MB,, Karl Franklin, Diana Berggren MD PhD, Marie Marklund DDS PhD, Hans Stenlund, and Ake Dahlqvist MD PhD, all from the University of Umea, Sweden . Their findings are to be presented at the American Academy of Otolaryngology--Head and Neck Surgery Foundation Annual Meeting and OTO EXPO, September 22-25, 2002, at the San Diego Convention Center, San Diego, CA.

Methodology: The subjects in the study were 596 men and 205 women referred with suspected sleep apnea syndrome between August 1997 and May 2000. A standardized ear, nose, and throat examination was performed, with evaluation of obstruction of the nose, the size of the tonsils and uvula, the height and retro-position of the tongue, the position of the mandible, the distance between the uvula and pharyngeal wall, and gag reflexes. A sleep study was then conducted on each.

The apnea/hypopnea index (AHI) was calculated from the number of apneas (>/= 10s) and hypopneas per hour sleep, and sleep apnea was defined as a score greater or equal to five. Body mass index (BMI) was calculated from the recorded height and weight.

Results: Female subjects seeking medical help for sleep apnea were older, had a higher BMI, and had a lower apnea index, when compared with men. Men more often had an obstruction in the nose, a larger uvula, a shorter distance between the uvula and the pharyngeal wall. This differed from women who revealed a more marked retro-position of the tongue and tended to have more gag reflexes. In women, BMI and the size of the uvula was associated with AHI; in men, the index score was associated with the BMI, the height of the tongue, the size of the uvula, the distance between the uvula and the pharyngeal wall.

Using a univariate analysis, the primary predictors for sleep apnea in women were the size of the uvula and the position of the mandible; using a multivariate analysis, tonsil size and mandible position remained significant predictors. For men, an univariate analysis revealed the distance between the uvula and the pharyngeal wall, height of the tongue, and body mass index as predictors for sleep apnea. These parameters remained significant using a multivariate analysis (backward stepwise method): the distance between the uvula and the pharyngeal wall, height of the tongue and BMI.

Conclusions: Scores indicating a propensity for sleep apnea for men and women are associated with BMI and the size of the uvula. But for men alone, the easily identifiable predictive features for this disorder are a high position of the tongue, a decreased distance between the uvula and the pharyngeal wall; in women, a retro-position of the mandible and large tonsils seem to be the primary risk factors for obstructive sleep apnea.

Learn more about snoring and obstructive sleep apnea at http://www.entnet.org/healthinfo/snoring/snoring.cfm.