About half of the world’s population suffers from headaches and migraines annually, new research this week has found, while roughly one in every seven people have a headache on any given day. The findings might suggest that migraines in particular have become more common over time, but the authors caution that the data isn’t clear enough to know for sure.
The study is the work of brain researchers in Norway and the UK and is a review of the medical literature on headache prevalence. The authors looked at more than 350 studies, all the way up through 2020.
Based on these studies, they estimated that 52% of people worldwide experience headaches every year, with women experiencing them more often than men. More specifically, 26% of people experience tension-type headaches annually, while 14% suffer from migraines and about 5% deal with headaches that last longer than 15 days on average a month. They also estimate that about 15% of people have had headaches in the past day.
The study, published Tuesday in The Journal of Headache and Pain, is an update to a paper by the same team published in 2007. Since then, other researchers have tried to track the worldwide prevalence of headaches, most notably scientists involved with the Global Burden of Disease project. The new findings are in line with these past estimates, the authors say, and show that headache disorders remain a common problem worldwide.
That said, the authors also tried to figure out why the reported rate of headaches can sometimes vary widely from study to study or between different regions of the world. They found that common methodical factors, such as how people are asked about their symptoms, can explain about 30% of the variation found between studies.
After accounting for these factors, the data does seem to suggest that migraines have genuinely become more common in recent years and that there are distinct regional differences in the likelihood of having headaches. That could signal a change in the causes of headache over time, such as greater exposure to air pollution or stress, or indicate the influence of genetics on different populations. But the researchers also say there may be other, less obvious factors in how studies are conducted that can explain this variation. So for now, they say that it’s still uncertain whether these apparent differences over time and region are real.
“What is clear is that overall, headache disorders are highly prevalent worldwide and can be a high burden,” said study author Lars Jacob Stovner, a researcher at the department of neuromedicine and movement science at the Norwegian University of Science and Technology, in a statement. “It may also be of interest in [the] future to analyse the different causes of headaches that varied across groups to target prevention and treatment more effectively.”
Future studies, the team says, should try to use the same standardised measures to track headache prevalence, and they should ideally come from all parts of the world, not just from high-income countries like the U.S., where the majority of past studies have been conducted so far.