Hagen K, et al. - In this large-scale population-based study, researchers assessed the cross-sectional connection between high sensitivity C- reactive protein (hs-CRP) and types of headache, and ascertained if the link to insomnia could be reproduced. In total of 50,807 out of 94,194 invited aged ≥ 20 years or older partook in the third wave of the Nord-Trøndelag Health Study study performed in 2006–2008. Of these, 38,807 had valid hs-CRP measures and answered headache and insomnia questions. Elevated hs-CRP, defined as > 3.0 mg/L, was linked to migraine and migraine with aura in the fully adjusted model. For any headache, migraine, and migraine with aura, the connection was strongest among people with headache ≥ 15 days/month. There was no clear connection between elevated hs-CRP and headache less than 7 days/month or with insomnia.