Study objective: To evaluate the relationship between
obstructive sleep apnea (OSA) and ventilatory responsiveness to carbon
dioxide in both men and women.
Design: An analysis of
219 patients referred to an university-based sleep center between 1989
to 1994 was conducted (104 with OSA and 115 without OSA; 43 women and
176 men). These patients had spirometry and a daytime hypercapnic
ventilatory response (HCVR) test that was corrected to the patient’s
ability to attain maximal ventilation. Comparisons between OSA
and no-OSA groups, as well as between men and women, were made using
multivariate modeling techniques.
Results: There was
no significant difference in the slope of correlated HCVR (cHCVR)
between those with and without OSA (1.57 ± 0.57 vs 1.63 ± 0.66;
p = 0.48). In men, an inverse correlation between daytime
Pco2 and cHCVR was observed in both crude and
multivariate analyses (crude β-coefficient = − 0.04 ± 0.02,
p = 0.02; adjusted β-coefficient = 0.07 ± 0.02, p < 0.01).
Although age and cHCVR did not share a significant relationship in the
crude analysis (crude β-coefficient = − 0.01 ± 0.01,
p = 0.10), with adjustments for confounding variables, a significant
inverse relationship between age and cHCVR was observed
(β-coefficient = − 0.02 ± 0.01, p = 0.04). On the other
hand, in women, only body mass index (BMI) was positively correlated
with cHCVR (crude β-coefficient = 0.03 ± 0.01, p = 0.01;
adjusted β-coefficient = 0.04 ± 0.01, p < 0.01).
Conclusion: OSA disorder is not associated with a blunted
ventilatory chemoresponsiveness to carbon dioxide. Elevated
Paco2 and older age are significant correlates
for a low cHCVR in men. For women only, BMI was associated with cHCVR.
These findings suggest that men and women may have different
ventilatory control mechanisms.