HIF1A and obstructive sleep apnea syndrome: As shown in Figure 1, the levels of HIF‐1α were significantly increased in the plasma samples of both mild and severe OSAHS patients compared with the controls (Figure 1, P < .01); moreover, the level of HIF‐1α was significantly increased in severe OSAHS group compared with the mild‐moderate group (Figure 1, P < .01).