A5839 Does Elevated Aldosterone in Obstructive Sleep Apnea Repress Surfactant Protein-B in Middle-aged Males? A Cross-sectional Study

Abstract

Objectives: To investigate the association of plasma aldosterone concentration (PAC) and serum surfactant protein levels in middle-aged males with obstructive sleep apnea (OSA). Methods: This is a cross-sectional study. Consecutive males with OSA were enrolled (apnea hypopnea index, AHI ≥ 5 event/hour). PAC and surfactant proteins (SPs, including SP-A, B, C and D) were measured. Subjects were divided into two groups, based PAC median as higher (PAC ≥ 15ng/d) and lower (PAC < 15ng/dl) groups. Serum concentrations of SPs were compared between groups and the potential association of PAC with key variables was then evaluated by univariate and multiple linear regression analysis. Results: 86 male subjects with OSA were enrolled for the current final analysis, with mean age 45 ± 7 years, body mass index (BMI): 27.8 ± 2.8 Kg/m2 and AHI 20.71 ± 12.80event/h. Higher and lower PAC groups showed no significant differences in terms of age, BMI, waist and neck circumference, smoking history and sleep-related parameters. Higher PAC group showed significantly lower serum SP-B concentrations (40.10 ± 5.76 vs 43.16 ± 6.89ng/L, p = 0.038) than did lower PAC group. Partial correlation analysis showed a negative significant correlation between SP-B and PAC (r = –0.361, p = 0.043), after controlling AHI but not among other parameters. Multiple linear regression analysis showed that SP-B was negatively associated with PAC (β = −0.234, P = 0.032), independent of AHI, and mean oxyhemoglobin aturation. Conclusion: Higher concentrations of PAC might repress synthesis of SP-B in condition of OSA, presented as decreased serum SP-B, which needs further confirmation.