APOA5 and obstructive sleep apnea syndrome: The HDL-C level was significantly lower in severe OSAHS than in mild OSAHS (P < 0.05) (Fig. 1a) and the ApoM and ApoA5 levels were both significantly lower in each severity of OSASHS patients than in the healthy controls (P < 0.05) (Fig. 1b, c).