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Original Investigation
August 2017

Association of a Family History of Atrial Fibrillation With Incidence and Outcomes of Atrial Fibrillation: A Population-Based Family Cohort Study

Author Affiliations
  • 1Cardiovascular Department, Chang Gung Memorial Hospital, Linkou, Taiwan
  • 2College of Medicine, Chang Gung University, Taoyuan, Taiwan
  • 3Division of Rheumatology, Orthopedics and Dermatology, School of Medicine, University of Nottingham, Nottingham, England
  • 4Division of Rheumatology, Allergy and Immunology, Chang Gung Memorial Hospital, Taoyuan, Taiwan
  • 5Division of Pediatric Neurology, Chang Gung Memorial Hospital, Linkou, Taiwan
  • 6Department of Public Health, College of Medicine, Chang Gung University, Taoyuan, Taiwan
  • 7Biostatistics Core Laboratory, Molecular Medicine Research Centre, Chang Gung University, Taoyuan, Taiwan
  • 8Office for Big Data Research, Chang Gung Memorial Hospital, Taoyuan, Taiwan
JAMA Cardiol. 2017;2(8):863-870. doi:10.1001/jamacardio.2017.1855
Key Points

Question  Is a family history of atrial fibrillation associated with a higher incidence of atrial fibrillation or worse outcomes?

Findings  In a nationwide population-based study of more than 23 million people in Taiwan, individuals who had first-degree relatives with atrial fibrillation had a mildly increased risk of new atrial fibrillation. Once atrial fibrillation had been diagnosed, family history was not associated with more major adverse cardiovascular events.

Meaning  Family history may be helpful in the diagnosis but not the management of atrial fibrillation.


Importance  The heritability of atrial fibrillation (AF), the contribution of genetic and environmental factors, and the association of a family history of AF with prognosis are unclear.

Objectives  To measure genetic and environmental factors in the familial aggregation of AF and to estimate the association of a family history of AF with major adverse cardiovascular events (MACE).

Design, Setting, and Participants  In this Taiwanese nationwide population-based study among more than 23 million people, a custom data set was obtained using the data of all patients having a diagnosis of AF recorded between January 1996 and December 2013 in the Taiwan National Health Insurance Research Database. The study population comprised all 23 422 955 individuals registered with the database in 2013, of whom 177 770 had a diagnosis of AF and were included in the heritability estimation. From the latter, a subgroup of patients having newly diagnosed AF with a first-degree relative affected by AF between 2000 and 2010 were selected and matched 1:4 to controls without a family history for estimating MACE-free survival. The dates of analysis were January 2010 to December 2013.

Main Outcomes and Measures  The prevalence and relative risk of AF in relatives of patients with AF, as well as the relative contributions of heritability and shared and nonshared environmental factors to AF susceptibility. Also measured was MACE-free survival after AF was diagnosed.

Results  In total, 1510 patients (204 [13.5%] female; mean [SD] age, 57.9 [9.2] years) had newly diagnosed AF with a first-degree relative affected by AF. Individuals with a first-degree relative affected by AF had a relative risk of 1.92 (95% CI, 1.84-1.99) for AF. The accountability for the phenotypic variance of AF was 19.9% for genetic factors (heritability), 3.5% for shared environmental factors, and 76.6% for nonshared environmental factors. After matching for age, sex, hypertension, type 2 diabetes, previous stroke, and anticoagulation, incident AF patients with vs without an affected first-degree relative had similar MACE-free survival.

Conclusions and Relevance  Genetic and environmental factors were associated with AF, with nonshared environmental factors accounting for three-fourths of the phenotypic variance in Taiwan. Patients having AF with a first-degree relative affected by AF did not have more MACE. Therefore, family history may not be particularly informative in the diagnosis or management of AF.