CHRM4 and Headache: CHRM1 rs2067477 has previously been linked to WHR adjusted for BMI [58] and the waist-to-hip index [59], while CHRM4 rs2067482, although not previously associated with metabolic conditions, has been implicated in headache or migraine [60], postoperative delirium, and postoperative cognitive dysfunction [56], as well as schizophrenia [61].