Bone Metabolism In Patients With OSAS And The Effects Of Nasal Continuous Positive Airway Pressure On Their Vascular Functions

Part Ⅰ Changes in bone turnover markers and bone mineral density in patients with OSASObjective:To investigate the changes in bone turnover markers and bone mineral density in patients with obstructive sleep apnea syndrome(OSAS).Methods:Forty five male patients with OSAS and forty healthy male individuals with matched age were included in the study.All participants underwent physical examination,polysomnography(PSG)monitory and bone mineral density measurement.Serum levels of the bone formation marker procollagen type I N-terminal propeptide(P1NP)and resorption marker C-terminal telopeptide of type I collagen(β-CTX)were measured.Results:The measured bone mineral densities of the OSAS group were significantly lower than those of the control group.Serum P1NP and β-CTX were significantly higher in the OSAS patients in comparison with the controls[P1NP:(63.2 ± 15.8)vs(41.6±13.6)ng/ml;β-CTX:(498.2± 123.7)vs(346.2± 106.4)pg/ml,P<0.05].Serum P1NP and β-CTX of the OSAS patients were positively correlated with apnea hypopnea index,the correlation index are 0.421 and 0.496 respectively CP<0.05).Conclusion:High bone turnover and low bone mineral density were observed in the patients with OSAS.It is necessary to evaluate bone loss in these patients and to introduce therapeutic interventions to prevent osteoporosis.Part Ⅱ The effects of CPAP on vascular functions in patients with OSASObjective:To investigate the effects of nasal continuous positive airway pressure(nCPAP)on vascular functions in patients with obstructive sleep apnea syndrome(OSAS)·Methods:We enrolled 28 moderate and severe patients with OSAS,and measured apnea hypopnea index(AHI),fasting blood glucose,fasting insulin,high-sensitivity C-reactive protein(hs-CRP),carotid-femoral pulse wave velocity(cf-PWV)and flow-mediated dilation(FMD).After nCPAP treatment for 4 months,these tests were performed again.Results:After nCPAP,AHI decreased from 56±22/h to 5.0±2.0/h,cf-PWV decreased from1124±212 cm/s to 987±171 cm/s,and FMD was improved from 6.32±2.18%to 7.54±3.04%.Meanwhile FINS、HOMA-IR and hs-CRP decreased significantly after nCPAP.Conclusion:The nCPAP treatment could decrease risks of cardiovascular complications in OSAS patients through improving vascular functions.