Familial aggregation of lone atrial fibrillation in young persons.
OBJECTIVE
This study investigated whether an individual's risk of developing lone atrial fibrillation (AF) before age 60 years is associated with lone AF in relatives.


BACKGROUND
Genetic factors may play a role in the development of lone AF.


METHODS
Using Danish national registers, a cohort was established of ~4 million persons born between 1950 and 2008, and those with a family history of lone AF (AF without preceding cardiovascular/endocrine diagnoses) were identified. Individuals were followed up until the first diagnosis of lone AF. Poisson regression was used to estimate incidence rate ratios (IRRs).


RESULTS
In ~92 million person-years of follow-up, 9,507 persons were identified as having lone AF. The IRRs for lone AF given an affected first- or second-degree relative were 3.48 (95% confidence interval [CI]: 3.08 to 3.93) and 1.64 (95% CI: 1.04 to 2.59), respectively. IRRs were higher for men than for women but were not associated with the affected relative's sex. IRR for lone AF was 6.24 (95% CI: 2.59 to 15.0), given at least 2 first-degree relatives affected with lone AF. The IRR for lone AF in persons aged <40 years given a first-degree relative affected at age <40 years was 5.42 (95% CI: 3.80 to 7.72), and 8.53 (95% CI: 3.82 to 19.0) in persons age <30 years given a first-degree relative affected at age <30 years.


CONCLUSIONS
A family history of lone AF is associated with substantial risk of lone AF, with the strongest risks associated with young age at onset, multiple affected relatives, and in first-degree relatives. These results suggest routine evaluation of the families of at least certain types of patients with lone AF.
Department of Epidemiology Research, Statens Serum Institut, Copenhagen, Denmark.
Nina
N
Oyen
Mattis F
MF
Ranthe
Lisbeth
L
Carstensen
Heather A
HA
Boyd
Morten S
MS
Olesen
Søren-Peter
SP
Olesen
Jan
J
Wohlfahrt
Mads
M
Melbye
D000293:Adolescent; D000328:Adult; D017668:Age of Onset; D001281:Atrial Fibrillation / Q000453:epidemiology* / Q000235:genetics*; D002648:Child; D002675:Child, Preschool; D015331:Cohort Studies; D015986:Confounding Factors, Epidemiologic; D003718:Denmark / Q000453:epidemiology; D005190:Family; D005260:Female; D020022:Genetic Predisposition to Disease; D006801:Humans; D015994:Incidence; D007223:Infant; D008297:Male; D008487:Medical History Taking; D008875:Middle Aged; D016017:Odds Ratio; D016012:Poisson Distribution; D012042:Registries; D012107:Research Design; D012306:Risk; D012307:Risk Factors