Relationship Of Pulmonary Function With Obstructive Sleep Apnea Hypopnea Syndrome And Metabolic Disorder

Purpose: Obstructive sleep apnea hypopnea syndrome(OSAHS) is a common sleep disorder. However, the relationship of pulmonary function with OSAHS and components of metabolic syndrome(MS) remains unclear. The aim of the present cross-sectional study was to investigate whether components of MS and metric of OSAHS are independently associated with pulmonary function and the potential mechanism by enrolling consecutive non-smoking patients who presented to our sleep laboratory because of symptoms of snoring.Methods: Consecutive patients who underwent standard polysomnography and diagnosed OSAHS between January 2014 to January 2015 were enrolled. Fasting blood samples were obtained from all patients for biological profile measurements and demographic data were collected. Pulmonary function test(including pulmonary ventilation function and pulmonary diffusing capacity) were completed after overnight PSG. Subjects were divided into mild to moderate, severe and very severe groups according to the apnea-hypopnea index(AHI).Results: A total of 79 non-smoking subjects including 56 males and 23 females were enrolled in our study during this period; the mean age was 48.49±11.64 years. The mean body mass index(BMI) was 26.83±3.52Kg/m2. Hemoglobin, serum insulin and homeostasis model assessment of insulin resistance(HOMA-IR) significantly increased with the aggravation of OSAHS.HDL-C significantly decreased with the aggravation of OSAHS.A statistically significant positive association was observed between OSAHS severity and the indices of total lung capacity(TLC) percentageof predicted value, the ratio of diffusing capacity for carbon monoxide to alveolar volume corrected for hemoglobin(DLCO/VA-Hb)( p=0.046, AND p=0.017, respectively). Multiple linear regression analyses were performed to evaluate the independent predictors of diffusing capacity for carbon monoxide corrected for hemoglobin(DLCO-Hb) and DLCO/VA-Hb. These analyses identified age(β=-0.56, p=0.000), gender(β=-0.447, p=0.000) as independent explanatory variables for DLCO-Hb(r square=0.613, adjusted r square=0.603), age(β=-0.563, p=0.000), AHI(β=0.256, p=0.007) and TG(β=-0.240, p=0.011) for DLCO/VA-Hb(r square=0.413, adjusted r square=0.389).Conclusions: In OSAHS subjects, AHI, triglycerides(TG) and age are independently associated with pulmonary diffusing capacity assessed by DLCO/VA-Hb. The factors mentioned above should be considered in order to more accurately understand the pulmonary diffusing capacity of OSAHS patients. Large sample researches are needed to further confirm the relationship between OSAHS and pulmonary function.