SHBG and obstructive sleep apnea syndrome: Those included studies with data not suitable for meta‐analysis reported significant associations between total [45, 48, 54] and free [45, 52, 53, 55, 59] testosterone, SHBG [55], androstenedione [48] and/or oestradiol [54] with OSA, while others did not [30, 31, 37, 46, 50, 51, 53, 55, 56, 59] (Supporting Information S1: 7).