OSA occurs when the soft tissues at the back of the throat temporarily collapse during sleep, blocking the airways. The result is numerous stops and starts in breathing during the night, with chronic, loud snoring being one sign of the condition. Daytime sleepiness is another, because the constant breathing interruptions disrupt sleep.

Dr. Elizabeth Beothy and colleagues at the University of Pennsylvania, Philadelphia, examined the relationships among race, menopausal status and OSA symptoms in 269 African American and white women whose average age was 48 years. According to the team, 37.5 percent of the women were premenopausal, 43 percent were in the menopausal transition, and 19.5 percent were postmenopausal. About half of the women were African American.

The researchers discovered that the average apnea score among African American women was nearly double that of white women. The researchers aren't sure why there were racial differences in OSA, but they say it's something that should be studied further.

Menopausal status, body mass index (BMI) and BMI over time were not significant predictors of OSA symptoms. BMI is the ratio of weight to height and is a standard method of determining if a person is underweight or overweight. Being overweight is a known risk factor for OSA.

However, among the menopausal women, OSA symptoms increased with higher BMI and larger BMI increases over time.

OSA affects an estimated 15 to 20 million Americans; millions more remain undiagnosed and untreated.

A therapy called CPAP, which stands for continuous positive airway pressure, is currently considered the most effective treatment for OSA. It involves wearing a face-mask through which the device delivers pressurized air to keep the airways open during sleep.