In females, the association between APOE polymorphisms and pain was substantially weaker and found only for carriers of APOE-ε4 who have reduced risk to develop chronic back pain (OR = 0.45, p = 0.0007), and headaches (OR = 0.65, p = 0.0045) (Fig. 5d and Supplementary Data 6). The gene discussed is APOE; the disease is Headache.