IL18R1 and Headache: Among these associations, 108 proteins were associated with headache, of which C4BPB (odds ratio [OR]  =  1.59, P = 1.67 × 10−39), IL18R1 (OR = 1.55, P = 7.36 × 10−25), and CDHR5 (OR = 1.46, P = 6.31 × 10−23) had the strongest associations.