Migraines and tension headaches are more prevalent and debilitating than we thought

Although migraine and other types of headache are common worldwide, headache disorders have become recognized as a major cause of morbidity and disability only within the last 20 years. In 2016, nearly 3 billion people worldwide had a headache disorder, including 1.04 billion with migraine and 1.89 billion with tension-type headache, according to estimates from a recent analysis in The Lancet.

“Headache is not limited to the high-income part of the world and, unless action is taken, it is here to stay,” wrote the authors—a collaboration of more than 50 researchers who reviewed data from the Global Burden of Diseases, Injuries, and Risk Factors (GBD) 2016 study to provide comprehensive information on incidence as well as years of life lived with disability (YLDs) for those who suffer from migraines or tension-type headaches.

For their analysis, the researchers examined the disease burden associated with migraines and tension-type headaches as well as medication overuse headache.

They calculated YLDs from the prevalence of the headache disorder as well as the average time spent with that type of headache, multiplied by its associated disability weight. The authors determined the disability weight for migraines to be 0.434, which means that during a migraine attack, the migraineur experiences a 43.4% health loss compared to a healthy person. The disability weight was 0.223 for medication overuse headache and 0.037 for tension-type headache.

To calculate the average time headache sufferers spent during attacks, which is necessary for the YLD calculation, the authors utilized population-based studies that included data on frequency and duration of headaches. Using these studies, the authors estimated that migraineurs spend an average of 8.5% of the year in migraine attacks. Those with tension-type headaches spend 4.7% of the year suffering from their headaches.

Migraines were estimated to cause 45.1 million YLDs in 2016, whereas tension-type headaches caused 7.2 million, leading to a combined 52.3 million YLDs, which comprised 6.5% of all YLDs worldwide.

The authors also investigated the relationship between headache and sociodemographic index, and found that headaches are not linked to socioeconomic status.

Among the 328 diseases examined by the GBD, tension-type headache was the third most common disorder worldwide and migraine was the sixth. Furthermore, headaches were found to be most debilitating in individuals aged 15-49 years, causing 9.5% of all YLDs in this age group. The majority of these individuals were women.

“Headache, and in particular, migraine, is a large public health problem in both sexes and all age groups worldwide, but most so in young and middle-aged women,” the authors wrote.

The authors acknowledged some limitations to their analysis. For instance, few studies that they reviewed provided data on the average time headache sufferers spend during attacks. Another limitation was the missing epidemiological data from many parts of the world.

“Even if it proves difficult to establish, with reasonable certainty, that modifiable risk factors exist for headache, the results of GBD definitely give a strong call for improving health care for headache,” the authors concluded. “In high-income parts of the world, the results presented here also highlight a strong moral obligation to allocate more resources to research aimed at understanding the mechanisms of headache to enable development of more effective prevention and treatments.”