APOA5 and obstructive sleep apnea syndrome: The purpose of this study was to investigate the correlation between serum levels of serum apolipoprotein M (ApoM), A5 (ApoA5), and high-density lipoprotein (HDL) in patients with obstructive sleep apnea hypopnea syndrome (OSAHS) and study the effects of nasal continuous positive airway pressure treatment on these serum biomarkers.