Cluster headaches are short but extremely painful headaches that can occur many days, or even weeks, in a row. Now a new study has found that people who have this debilitating form of headache may miss twice as many days of work as people without such headaches. The study is published in the February 5, 2020, online issue of Neurology^®, the medical journal of the American Academy of Neurology.

Cluster headaches can last anywhere from 15 minutes to 3 hours and usually occur above or around the eye. They are more common in men. About one of every 1,000 people in the United States has cluster headaches.

“This study shows that cluster headaches dramatically interfere with people’s work capacity,” said study author Christina Sjöstrand, MD, PhD, of the Karolinska Institutet in Stockholm, Sweden. “More research is needed on how to best treat and manage this form of headache so people who experience them have fewer days in pain and miss fewer days of work.”

Researchers looked at data from two Swedish national registries to identify study participants. They included all people of working age who had been treated for cluster headaches in a hospital or by a specialist between 2001 and 2010—a total of 3,240 people. They also included 16,200 people from the general population who did not have cluster headaches who were matched for age, sex, education and hometown.

“One strength of our study was that we included all people whether they were working, unemployed, or on parental leave, so that our study results would more accurately reflect the entire population and not just people who were healthier,” said Sjöstrand.

Researchers then used a registry to determine the number of sick days and disability days taken in 2010 by each study participant. Researchers only included information on sick leaves that lasted longer than 2 weeks. The average number of sick days for people with cluster headaches was 16 while the average number for people without cluster headaches was just under 7 days. When researchers added in days taken for disability, people with cluster headaches had an average of 63 sick and disability days compared to 34 among those without cluster headaches.

People with cluster headaches who had less education had more sick and disability days than those with more education. Those who completed only elementary school had an average of 86 sick and disability days, compared to an average of 65 days for those with a high school education and 41 days for those with a college education.

Women with cluster headaches had twice as many sick days than men, an average of 24 days compared to 12 days. When adding disability days, women had an average of 84 days compared to an average of 53 days for men.

“While it is believed that men and women experience cluster headaches in mostly similar ways, it may be that we do not yet have a full picture of sex differences in the disease,” said Sjöstrand. “The reason for these sex differences are unclear and more studies are needed.”

A limitation of the study was that it may have missed people treated for cluster headaches only in primary health care clinics. Due to this, the people included in this study may be those who experience more severe cluster headaches.