title: The association between prolonged fatigue and cardiovascular disease in World War II veteran twins.
abstract: Reports of fatigue preceding cardiac events have recently been confirmed by large prospective studies. To assess for genetic confounding, we investigated prolonged fatigue and cardiovascular disease (CVD) in a cohort of World War II veteran twins. We examined data from a questionnaire mailed to members of the National Academy of Sciences-National Research Council (NAS-NRC) World War II Twins Registry in 1998 and 1999 which included questions on demographics, medical conditions and symptoms of fatigue. Data from twins discordant for prolonged fatigue lasting a month or more were analyzed using conditional logistic regression. Among 1955 twin pairs, 157 monozygotic and 174 dizygotic pairs (mean age 74 years) were discordant for prolonged fatigue. An association was found between prolonged fatigue and a history of myocardial infarction or coronary artery surgery adjusting for age, socioeconomic status, smoking, alcohol use and depression (OR [Odds Ratio]: 2.2; 95% CI: 1.3-4.0). When analyses were performed separately by zygosity, the association was slightly larger for monozygotic (OR: 3.3; 95% CI: 1.2-9.1) than dizygotic twins (OR: 1.9; 95% CI: 0.9-4.0). These data corroborate the association of fatigue with CVD and suggest that it is not influenced by a common genetic factor. Further studies are needed to clarify the relationship and to better understand the biologic mechanisms.
authors.affiliation: Department of Epidemiology, University of Washington, Seattle, Washington 98115, USA. fitzpal@u.washington.edu
authors.forename: Annette L
authors.initials: AL
authors.lastname: Fitzpatrick
authors.forename: Terry
authors.initials: T
authors.lastname: Reed
authors.forename: Jack
authors.initials: J
authors.lastname: Goldberg
authors.forename: Dedra
authors.initials: D
authors.lastname: Buchwald
mesh_terms: D000367:Age Factors; D000368:Aged; D000428:Alcohol Drinking; D002318:Cardiovascular Diseases / Q000209:etiology*; D015331:Cohort Studies; D003863:Depression; D005221:Fatigue / Q000150:complications*; D006801:Humans; D016015:Logistic Models; D008297:Male; D012307:Risk Factors; D012907:Smoking; D012959:Socioeconomic Factors; D011795:Surveys and Questionnaires; D014427:Twins; D014728:Veterans / Q000706:statistics & numerical data; D047789:World War II