(HealthDay News) – Half of adult women aged 20–70 years may have obstructive sleep apnea, which correlates with age, obesity, and hypertension.

Karl A. Franklin, MD, PhD, from Umeå University in Sweden, and colleagues examined the frequency of sleep apnea among women in the general population using data from 400 women from a population-based random sample of 10,000 women (aged 20–70 years). Participants completed a questionnaire and performed overnight polysomnography.

The researchers found that 50 percent of the women had obstructive sleep apnea (apnea-hypopnea index of ≥5). Age, obesity, and hypertension were related to sleep apnea, but daytime sleepiness was not. Fourteen percent of women aged 55–70 years and 31% of obese women with a body mass index >30kg/m² aged 50–70 years had severe sleep apnea (apnea-hypopnea index of ≥30). Two distinct phenotypes of obstructive sleep apnea were observed: sleep apnea with daytime sleepiness and sleep apnea with hypertension.

“We were very surprised to find such a high occurrence of sleep apnea in women, as it is traditionally thought of as a male disorder,” Franklin said in a statement. “These findings suggest that clinicians should be particularly aware of the association between sleep apnea and obesity and hypertension, in order to identify patients who could also be suffering from the sleeping disorder.”