Danish Headache Center, Department of Neurology, Glostrup Hospital, University of Copenhagen, Nordre Ringvej, Building 23, DK-2600 Glostrup, Copenhagen, Denmark. buchgreitz@dadlnet.dk
Altered pain sensitivity is believed to play an important role for chronification of headache. It has however mainly been evaluated in highly selected patients from headache clinics and never in longitudinal studies. The present study is a 12-year follow-up of a population-based study of primary headache disorders and pain perception, combining a diagnostic headache interview with examination of muscle tenderness and measurement of pressure pain thresholds in 1000 subjects drawn randomly from the general population in Denmark. The aim of the study was to explore the cause-effect relationship between the increased pain sensitivity and the development of headache. The pressure pain thresholds were normal at baseline but had decreased at follow-up in subjects who developed chronic tension-type headache over the 12-year period (p = 0.025). In subjects who developed frequent episodic tension-type headache the tenderness was normal at baseline but had increased at follow-up (p