Birth weight is a significant risk factor for incident atrial fibrillation.
BACKGROUND
Few if any studies have assessed the relationship between birth weight and incident atrial fibrillation (AF).


RESULTS
From 1993 to 2009, we prospectively followed 27 982 women who were >45 years of age and free of cardiovascular disease and AF at baseline. Information on birth weight was categorized into 5 different categories: <2.5, 2.5 to 3.2, 3.2 to 3.9, 3.9 to 4.5, and >4.5 kg. The primary outcome was time to incident AF. During 14.5 years of follow-up, 735 AF events occurred. Age-adjusted incidence rates for incident AF from the lowest to the highest birth weight category were 1.45, 1.82, 1.88, 2.57, and 2.55 events per 1000 person-years of follow-up. After multivariable adjustment, hazard ratios for incident AF across increasing birth weight categories were 1.0, 1.30 (95% confidence interval [CI], 0.96 to 1.75), 1.28 (95% CI, 0.96 to 1.69), 1.70 (95% CI, 1.23 to 2.37), and 1.71 (95% CI, 1.12 to 2.61) (P for linear trend=0.002). Adding body mass index, blood pressure, and diabetes mellitus at study entry did not have a large effect on these estimates (P for linear trend=0.004). In contrast, including height in the multivariable model substantially attenuated the relationship between birth weight and AF (P for linear trend=0.17), and additional adjustment for maximum weight in young adulthood further attenuated this association (multivariable-adjusted hazard ratio across birth weight categories, 1.0, 1.27 [95% CI, 0.94 to 1.71], 1.10 [95% CI, 0.83 to 1.46], 1.41 [95% CI, 1.01 to 1.96], and 1.29 [95% CI, 0.84 to 1.98]; P for linear trend=0.23).


CONCLUSIONS
Birth weight is significantly associated with incident AF among women, suggesting that early life determinants may play an important role in the pathogenesis of AF.


BACKGROUND
URL: http://www.clinicaltrials.gov. Unique identifier: NCT00000479.
Conen
David
D
Center for Arrhythmia Prevention, Department of Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, Mass., USA. conend@uhbs.ch
Tedrow
Usha B
UB
Cook
Nancy R
NR
Buring
Julie E
JE
Albert
Christine M
CM
D001281:Atrial Fibrillation / Q000453:epidemiology / Q000209:etiology*; D001724:Birth Weight; D001827:Body Height; D005260:Female; D006801:Humans; D015994:Incidence; D007231:Infant, Newborn; D008875:Middle Aged; D011446:Prospective Studies; D012307:Risk Factors