A recent study published in Headache has established a link between headache disorders and the risk of new-onset hypothyroidism. Using data from the Fernald Medical Monitoring Program, Vincent Martin and colleagues found that individuals with headache disorders had a 21% increased risk of hypothyroidism, rising to 41% in patients with possible migraine. The longitudinal study design provided novel insights into the chronology of events, confirming that the headache disorders preceded the development of hypothyroidism.