"Most people with a mild head injury take off work for a week and then forget about it, but some end up with long-term ailments like headaches," says Lena Hoem Nordhaug, a PhD candidate in neuromedicine at the Norwegian University of Science and Technology (NTNU).
She recently published her findings in the The Journal of Headache and Pain.
Headaches became worse
The study shows that people who were hospitalized with a mild head injury had twice as high a risk of developing headaches, or exacerbating pre-existing headaches, than the rest of the population.
Nordhaug used numbers from the HUNT 2 and 3 Nord-Trøndelag Health Study, two large Norwegian epidemiological surveys, and linked them to hospitalizations due to head injuries. She included 294 individuals who had been hospitalized with head trauma in Trondheim, Levanger or Namsos in the eleven-year period between the HUNT 2 and 3 studies.
Falls are frequent cause of head injury
Most of the 211 individuals who had suffered a concussion - a mild head injury - reported a fall as the cause of their head trauma. Traffic accidents were the second most noted cause.
"Headaches are a major social problem. They lead to a reduced quality of life and labour loss, and are a very common complaint that especially affects women in the most active years of their lives, "says Nordhaug.
Previous research at NTNU shows that four out of ten Norwegian women and three out of ten Norwegian men are plagued by headaches.
"It's important to find out what distinguishes the head injury patients who suffer from long-term ailments from those who don't. Then the patients in the high-risk group could be followed more closely," says Nordhaug.
Head trauma in the US
Norway and several other countries are currently debating whether to implement a ban on heading in children's football.
The United States is one of the countries that have introduced a ban on heading the ball to minimize the risk of brain injury. Children under the age of 10 are not allowed to head the ball, and heading is restricted for children between the ages of 11 and 13.
"The U.S. is doing a lot of research on headaches after head injury," says Nordhaug.
She believes that may be due in part to the many veterans who have suffered head trauma in the United States.
"Many more people there experience repeated head injury from playing ice hockey and American football. You can't really compare someone who's been kicked in the head once by a cow on their farm with someone who's suffered a head injury in a chaotic war situation," says Nordhaug.
Different conditions in Norway
She also points out that the American health system is very different in terms of litigation and the possibility of compensation.
"All this means that numbers from the United States can't necessarily be directly compared with Norwegian statistics," says Nordhaug.
NTNU and St. Olavs Hospital in Trondheim have conducted a study based on everyone who comes to the hospital's urgent care with mild head injuries, in order to obtain more data about conditions in Norway. The results will soon be available.