Genetic epidemiological studies of the functional somatic syndromes : chronic widespread pain and chronic fatigue

摘要: Fibromyalgia and chronic fatigue syndrome are two symptom-defined conditions with many physical symptoms in common, such as muscle pain, fatigue, unrefreshing sleep, impairment memory or concentration. These often co-occur frequently co-exist other (e.g., irritable bowel recurrent headache), have a female predominance, share psychosocial psychiatric characteristics. It has been suggested that fibromyalgia, syndrome, can be considered syndromes underlying pathogenesis, hence named “functional somatic syndromes”. To date, little is known about the causes of functional their cooccurrence (comorbidity). The present study aimed at investigating etiology this comorbidity focus on widespread pain (the cardinal symptom fibromyalgia) fatigue. Data were obtained from participants Screening Across Lifespan Twins (SALT) population-based Swedish Twin Registry. All living, contactable, consenting twins born Sweden before December 1958 contacted between March 1998 2002 to participate computer-assisted telephone interview. Of 61,355 eligible twins, 44,897 individuals (73.2%) participated interview which screened, amongst others, for headache, major depression, generalized anxiety disorder. Zygosity was determined using questions regarding childhood similarity. Psychological risk factors (personality stress) assessed questionnaires administered monozygotic same-sex dizygotic 1972-73. Univariate multivariate twin analyses implemented order estimate relative importance genetic environmental influences assess sex differences estimates, determine etiological model best explains syndromes. Matched case-control co-twin performed evaluate associations its comorbid conditions, examine premorbid risks psychological familial (genetic family environmental) these associations. Modest no found pain. estimates did not differ significantly by sex. Strong followed magnitude syndrome. Associations disorders longer significant when discordant used, whereas most decreased but remained significant, suggesting Emotional instability perceived stress associated screened ≥ 25 years later subjects aged < 65. When association emotional increased severer definition different effects Finally, women latent traits shared four comorbidities. loaded only one traits, reflect affective non-affective (or physiological) aspects symptoms. Each illness also influenced specific each. In conclusion, attributed (one not) syndromes, among them attributable each illness. LIST OF PUBLICATIONS This thesis based following papers, referred text Roman numerals (I-IV). I. Kato K, Sullivan PF, Evengard B, Pedersen NL Importance Arthritis & Rheumatism 2006:54(5);1682-1686. © American College Rheumatology II. Chronic comorbidities: study. Archives Internal Medicine 2006:166(15);1649-1654. Medical Association III. Premorbid predictors General Psychiatry 2006:63(11);1267-1272. IV. A Submitted publication