Purpose: Endothelial dysfunction is one of the early markers of cardiovascular complications in obstructive sleep apnea (OSA). The aim of our study was to evaluate whether overweight patients with mild OSA displayed endothelial dysfunction, and to assess the effect of 1-year lifestyle intervention with an early very low calorie diet in endothelial function.
Methods: At baseline, the study population consisted of 83 overweight patients with mild OSA and 46 weight-matched non-OSA subjects. OSA patients were further randomized into a 1-year supervised lifestyle intervention group or control group which received routine lifestyle counselling. Endothelial function measured by brachial artery flow-mediated dilatation (FMD), apnea-hypopnea index (AHI), body mass index (BMI), and metabolic parameters were assessed at baseline and 12 months.
Results: No correlations between endothelial function and mild OSA were detected. However, patients with impaired endothelial function had lower mean saturation and impaired endothelial function correlated significantly with glucose intolerance and dyslipidemia. After the lifestyle intervention and successful weight reduction, AHI, BMI, serum triglycerides and insulin improved significantly; however, no improvement in FMD was detected.
Conclusions: Mild OSA was not observed to be associated with endothelial dysfunction. Although in mild OSA endothelial function is still preserved, lifestyle intervention with weight reduction did achieve an improvement in other obesity-related risk factors for cardiovascular diseases, thus highlighting the importance of early intervention.