Are people with cluster headaches more likely to have other illnesses?

Cluster headaches are short but extremely painful headaches that can occur many days, or even weeks, in a row. The headaches can last anywhere from 15 minutes to three hours.

"Around the world, headaches have an incredibly negative impact on people's quality of life, both economically and socially," said study author Caroline Ran, PhD, of the Karolinska Institutet in Stockholm, Sweden. "Our results show that people with cluster headaches not only have an increased risk of other illnesses, those with at least one additional illness missed four times as many days of work due to sickness and disability than those with just cluster headaches. They also have a higher chance of a long-term absence from work."

The study involved 3,240 people with cluster headaches from age 16-64 in Sweden who were compared to 16,200 people who were similar in age, sex and other factors. The majority were men, which is common with cluster headache.

Researchers looked at work records and disability benefits to determine how many days during a year people were absent from work due to sickness and disability.

Among those with cluster headaches, 92%, or 2,977 people, had at least one additional illness. Of those without cluster headaches, 78%, or 12,575 people, had two or more illnesses.

Of those with cluster headaches, more women had additional illnesses than men, 96% and 90% respectively.

The average number of days a person was absent due to sickness and disability was nearly twice as high among people with cluster headaches with 63 days compared to those without cluster headaches with 34 days.

People with cluster headaches and at least one additional illness had four times as many absence days compared to people with cluster headaches who did not have an additional illness.

"Increasing our understanding of the other conditions that affect people with cluster headache and how they impact their ability to work is very important," added Ran. "This information can help us as we make decisions on treatments, prevention and prognoses."

A limitation of the study was that information on personal data, such as smoking, alcohol consumption and BMI, which could affect the occurrence of diseases, was not available.

The study was supported by Swedish Research Council, Swedish Brain Foundation and Mellby Gård, Region Stockholm, Märta Lundkvist Foundation and Karolinska Institutet Research Funds.