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www.thelancet.com/neurology Vol 17 November 2018 929 Migraine is one of the most frequent neurological diseases, but its burden is generally underestimated, mainly because of the transient nature of primary headaches. In contrast to the perception that migraines are not a cause of substantial burden, migraine, together with low back pain, age-related and other hearing loss, iron-deficiency anaemia, and major depressive disorder, was one of the five leading causes of years of life lived with disability (YLDs) in 2016, according to an analysis of the Global Burden of Diseases, Injuries, and Risk Factors (GBD) study. According to a new analysis from the GBD study now reported in The Lancet Neurology, almost 3 billion people had a headache disorder in 2016: 1·89 billion had a diagnosis of tension-type headache and 1·04 billion had a diagnosis of migraine. Migraine was responsible for 45·12 million YLDs, with a peak in prevalence in women between ages 15 and 49 years. YLDs due to migraine increased from 1990 to 2016 and were higher than those due to tension-type headache, although tension-type headache was the more prevalent disorder. Migraine is a transient neurological disorder: it typically improves with the menopause in women, and more than 50% of patients with the diagnosis of chronic migraine remit spontaneously to episodic migraine within 3 years. Migraine and tension-type headache do not lead to permanent physical disability or sequelae, which stands in sharp contrast with the effects of progressive neurological disorders, such as multiple sclerosis or Parkinson’s disease. The transient symptoms make the estimation of the effect of migraine on a person’s life difficult. In their estimation of YLDs, the GBD 2016 Headache Collaborators used a disability weight, which reflects the loss of health during the time of acute migraine or tension-type headache as compared with a healthy person, showing that assessment of the burden of the disease is feasible. By use of disability-weight-adjusted YLDs, the effect of migraine, which accounts for as many as 5·6% of all YLDs, can be compared with the effect of progressive neurological disorders: 45·12 million YLDs could be attributed to migraine in 2016, whereas Parkinson’s disease accounted for 706 thousand YLDs and multiple sclerosis for 584 thousand YLDs. Migraine usually affects patients during the ages of 15–49 years, with a peak in prevalence between ages 35 and 39 years. Other progressive disorders lead to substantial burden typically in the later stages of life. Progressive neurological disorders should medical management keeps improving survival, and environ mental or social risk factors remain stable or increase, we can expect an even greater increase in the number of patients. I agree with Dorsey, Elbaz, and colleagues that there is an urgent need for research focusing on identifying new preventive interventions and new treatments for people with Parkinson’s disease. The preventive interventions might need to be tailored to men and women separately, and to specific countries or regions of the world.