A relationship between migraine and biliary tract disorders: findings in two Swedish samples of elderly twins Introduction Migraine, G43 according to ICD-10 (1), is a neurological disorder that generally involves iterated attacks of headache, often unilateral. Migraine represents a cluster of syndromes, classified according to the International Classifica- tion of Headache Disorders (ICHD-2), developed by the International Headache Society (IHS) (2). Sometimes there is an aura with characteris- tic visual disturbances and ⁄ or other neurological symptoms before the headache. The most common subtypes are migraine without aura (approximately 75%) and migraine with aura (approximately 20%). The distinction between types is not clear and there are cases with aura only at occasional migraine attacks. Owing to low medical care attendance there is a marked tendency to under- diagnose migraine. In a Scandinavian population based sample, only 56% of persons with migraine reported that they had consulted a doctor due to the disorder and only one third were current consulters (3). In many cases, nausea, vomiting, and other types of indicators are components of the migraine attacks. Upper abdominal symptoms are more frequent in patients with migraine than in healthy controls (4). Abdominal migraine includes epigas- tric discomfort with pain, bloating, anorexia, nausea, and a tendency to vomit (5). Further, photophobia, phonophobia, benign paroxysmal vertigo and less specific symptoms of dizziness may precede headache but can also appear sepa- rately, especially in children (6). Not only migraine Acta Neurol Scand 2010: 122: 286–294 DOI: 10.1111/j.1600-0404.2009.01310.x Copyright Ó 2009 The Authors Journal compilation Ó 2009 Blackwell Munksgaard ACTA NEUROLOGICA SCANDINAVICA Nilsson S, Edvinsson L, Malmberg B, Johansson B, Linde M. A relationship between migraine and biliary tract disorders: findings in two Swedish samples of elderly twins. Acta Neurol Scand: 2010: 122: 286–294. Ó 2009 The Authors Journal compilation Ó 2009 Blackwell Munksgaard. Objectives – To investigate whether there is a relationship between the clinical occurrence of migraine and biliary tract disorders (BTD) and to study whether there is a genetic influence on such an association. Materials and Methods – The near lifetime morbidity for migraine and BTD was examined in two Swedish twin-samples: OCTO-Twin (149 MZ and 202 DZ pairs; 234 men, 468 women; 80 years of age or older at inclusion), and the GENDER study (249 unlike-sex DZ-pairs; 70–80 years of age at inclusion). The diagnosis of BTD was established by perusal of medical records from the last twenty years. The diagnosis of migraine was based on iterated questionnaires and personal interviews. Results – The odds ratio (OR) of BTD among OCTO-Twin subjects suffering from migraine was 3.5 (1.9–6.7) in monozygotic pairs and 1.7 (1.0–2.9) in dizygotic pairs The corresponding figures among the GENDER unlike-sex DZ-pairs was 2.7 (1.6–4.5). Migraine was associated with female sex and waist circumference. Conclusions – There is a relationship between the occurrence of migraine and BTD, also when controlling for the fact that both disorders are more frequent in women. The association appears to be partly attributable to genetic influences. S. Nilsson 1 *, L. Edvinsson 2 , B. Malmberg 1 , B. Johansson 1,3 , M. Linde 4,5 1 Institute of Gerontology, Jçnkçping University, Jçnkçping; 2 Department of Internal Medicine, University Hospital of Lund, Lund; 3 Department of Psychology, University of Gothenburg, Gothenburg; 4 Norwegian National Headache Centre at the Department of Neuroscience, Norwegian University of Science and Technology, Trondheim, Norway; 5 Institute of Neuroscience and Physiology, The Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden Key words: cholecystopathy; gallbladder disease; inheritance; migraine; twins Mattias Linde, Cephalea Headache Centre, Läkarhuset, Sçdra vägen 27, SE-41135 Gothenburg, Sweden Tel.: +46 31 810900 Fax: +46 31 814259 e-mail: mattias.linde@neuro.gu.se *Deceased May 2009. Accepted for publication November 17, 2009 286