The effect of gender on the prevalence of hypertension in obstructive sleep apnea.

BACKGROUND: Obstructive sleep apnea (OSA) causes systemic hypertension. However, there is conflicting data on the effect of gender on susceptibility to hypertension in OSA. Some show no gender differences in the prevalence of hypertension while others report either female or male propensity to have hypertension in the context of OSA. The inconsistencies in the results appear to be due to lack of full range of sleep apnea severity and insufficient number of women in the studies. We examined the effect of gender on prevalent hypertension in a cohort with a large representation of females with OSA.
METHODS: A cross-sectional study of a large cohort of subjects referred for sleep disorder evaluation.
RESULTS: The cohort comprised of 736 with OSA and 315 without OSA. OSA was defined as apnea-hypopnea index (AHI) of 5/h. There were 529 men and 207 women in the OSA group with mean+/-SD age of 50+/-13 and 51+/-14 years, respectively. The control group consisted of 154 men and 161 women with mean+/-SD age of 44+/-15 and 43+/-14 years, respectively. The AHI in the OSA group varied from 5 to 197 with a median of 24 and a mean of 36 (interquartile range: 11-53). Multiple logistic regression analyses, modeling the association between AHI and hypertension and considering other covariates, showed that odds of hypertension increased with increasing age, BMI, and AHI. There was evidence that men were at higher risk for hypertension than women OR 1.82 (95%CI 1.01, 3.20) at the highest quartile of BMI.
CONCLUSIONS: We have shown that the prevalence of hypertension increases with increasing age and severity of OSA, and markedly obese men may have a nearly 2-fold greater risk for hypertension than women in this clinic-based population.