In a population-based study in Denmark, the lifetime prevalence of TTH was high (78%), but the majority had episodic infrequent TTH (1 day a month or less) without specific need for medical attention.[7] About 24% to 37% had TTH several times a month, 10% had it weekly, and 2% to 3% of the population had chronic TTH, usually lasting for the greater part of a lifetime.