title: Are infrequent episodic, frequent episodic and chronic tension-type headache inherited? A population-based study of 11 199 twin pairs.
abstract: The objective was to investigate the importance of genetic and environmental factors for infrequent episodic, frequent episodic and chronic tension-type headache. Twin pairs recruited from the population-based Danish Twin Registry received a posted questionnaire. Only twin pairs where both twins replied were included. A total of 3523 monozygotic (MZ), 4150 dizygotic (DZ) same-gender and 3526 DZ opposite-gender twin pairs were included. The prevalence of frequent episodic and chronic tension-type headache was significantly more frequent in women than men, and significantly higher in those with co-occurrence of migraine. The concordance rates were significantly higher in MZ than same-gender DZ twin pairs with no or frequent episodic tension-type headache, while the difference was not significant in chronic tension-type headache. The concordance rates of infrequent episodic tension-type headache in MZ and same-gender DZ twin pairs was significantly different in women but not in men, although the difference was small in both genders. We conclude that genetic factors play a role in no and frequent episodic tension-type headache, while infrequent episodic tension-type headache is caused primarily by environmental factors. The data regarding chronic tension-type headache were limited, so no firm conclusion could be drawn.
authors.affiliation: Head and Neck Research Group, Akershus University Hospital, Dr. Kobros vei 39, 1474 Nordbyhagen, Oslo, Norway. m.b.russell@medisin.uio.no
authors.forename: Michael Bjørn
authors.initials: MB
authors.lastname: Russell
authors.forename: Jūrate
authors.initials: J
authors.lastname: Saltyte-Benth
authors.forename: Niels
authors.initials: N
authors.lastname: Levi
mesh_terms: D000328:Adult; D002908:Chronic Disease; D003718:Denmark / Q000453:epidemiology; D004777:Environment; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D011153:Population; D012727:Sex Characteristics; D011795:Surveys and Questionnaires; D018781:Tension-Type Headache / Q000145:classification / Q000453:epidemiology* / Q000235:genetics*; D014429:Twins, Dizygotic; D014430:Twins, Monozygotic