People with a steep jaw line and a crowded or narrowed air passage at the back of the throat are at increased risk of obstructive sleep apnea (OSA), regardless of their weight or ethnic background, a study shows.

People with OSA suffer frequent, short periods during sleep when they stop breathing. The condition is linked to high blood pressure and other heart conditions.

“OSA is prevalent worldwide but is under-recognized and therefore under-treated,” said Dr. Frank Ryan from the University of British Columbia in Vancouver.

“The common denominator in the vast majority of patients with OSA is a narrowed or constricted airway at the back of the throat.”

Major factors leading to this airway narrowing include obesity, variations in facial bony structure or a combination of both, the researcher explained. Craniofacial abnormalities may be a more important factor in some ethnic groups, he said.

To see whether the craniofacial profile is predictive of OSA, Ryan and colleagues studied 239 consecutive patients who were referred to sleep clinics in Hong Kong and Vancouver for suspected sleep disordered breathing.

“Our study showed that, in a mixed sample of patients of both sexes that included whites and Asians, a crowded or narrowed air passage at the back of the tongue and soft palate and a steep jaw line were the best predictors of OSA, regardless of the patients’ ethnic group or their degree of obesity,” Ryan told.

Because these abnormalities of the craniofacial profile are easily identified on routine clinical examination, they are a potentially useful tip-off to the possibility of OSA, he added.

SOURCE: Thorax June 2005.