Study objectives: To compare the prevalence and
severity of sleep apnea between premenopausal and postmenopausal women,
and to determine whether these differences are affected by the body
mass index (BMI) and neck circumference.
Cross-sectional study utilizing a sleep clinic patient database.
Setting: University hospital.
total of 1,315 women, classified into premenopausal and postmenopausal
groups based on age (< 45 years and > 55 years, respectively).
Measurements: Anthropometric measurements included height,
weight, and neck circumference. Sleep measurements included full
nocturnal polysomnography. Sleep apnea was defined as an apnea-hypopnea
index (AHI) > 10/h.
Results: There were 797
premenopausal and 518 postmenopausal women. The latter group was more
obese (mean ± SE BMI, 32.2 ± 0.4 kg/m2 vs
30.2 ± 0.4 kg/m2; p < 0.0001) and had larger neck
circumference (37.1 ± 0.2 cm vs 35.8 ± 0.2 cm; p < 0.0001).
The prevalence of sleep apnea was greater in postmenopausal women than
premenopausal women (47% vs 21%; χ2 < 0.0001). There
were proportionately more postmenopausal than premenopausal women in
all ranges of apnea severity (AHI, 10 to 30/h, 30 to 50/h, and>
50/h). Postmenopausal women had a significantly higher mean AHI
compared to premenopausal women (17.0 ± 0.9/h vs 8.7 ± 0.6/h;
p < 0.0001); this significant difference persisted even after
adjusting for BMI and neck circumference.
There may be functional, rather than anatomic, differences in the upper
airway between premenopausal and postmenopausal women, which may
account for the observed differences in apnea prevalence and