Elevated levels of high-sensitivity C-reactive protein (hs-CRP) are associated with headaches occurring on more than seven days per month and migraine with aura, researchers say.

Almost 40,000 adults over the age of 20 took part in the population-based HUNT3 study in 2006-08, led by the Norwegian University of Science and Technology.

The cohort had an average age of 54, had answered questions about headache and insomnia, and had their hs-CRP levels measured in non-fasting blood samples.

The researchers defined normal hs-CRP as 3mg/L or below and elevated as 3.01–20mg/L.