title: Racial Differences in Left Atrial Size: Results from the Coronary Artery Risk Development in Young Adults (CARDIA) Study.
abstract: Whites have an increased risk of atrial fibrillation (AF) compared to Blacks. The mechanism underlying this association is unknown. Left atrial (LA) size is an important AF risk factor, and studies in older adults suggest Whites have larger LA diameters. However, because AF itself causes LA dilation, LA size differences may be due to greater subclinical AF among older Whites. We therefore assessed for racial differences in LA size among young adults at low AF risk. The Coronary Artery Risk Development in Young Adults (CARDIA) study enrolled White and Black participants between 18 and 30 years of age. LA diameter was measured in a subset of participants using echocardiography at Year 5 (n = 4,201) and Year 25 (n = 3,373) of follow up. LA volume was also assessed at Year 5 (n = 2,489). Multivariate linear regression models were used to determine the adjusted association between race and LA size. In unadjusted analyses, mean LA diameter was significantly larger among Blacks compared to Whites both at Year 5 (35.5 ± 4.8 mm versus 35.1 ± 4.5 mm, p = 0.01) and Year 25 (37.4 ± 5.1 mm versus 36.8 ± 4.9 mm, p = 0.002). After adjusting for demographics, comorbidities, and echocardiographic parameters, Whites demonstrated an increased LA diameter (0.7 mm larger at Year 5, 95% CI 0.3-1.1, p<0.001; 0.6 mm larger at Year 25, 95% CI 0.3-1.0, p<0.001). There was no significant association between race and adjusted Year 5 LA volume. In conclusion, in a young, well-characterized cohort, the larger adjusted LA diameter among White participants suggests inherent differences in atrial structure may partially explain the higher risk of AF in Whites. The incongruent associations between race, LA diameter, and LA volume suggest that LA geometry, rather than size alone, may have implications for AF risk.
authors.affiliation: Electrophysiology Section, Division of Cardiology, Department of Medicine, University of California San Francisco, San Francisco, California, United States of America.|Knight Cardiovascular Institute, Oregon Health & Science University, Portland, Oregon, United States of America.
authors.forename: Thomas A
authors.initials: TA
authors.lastname: Dewland
authors.affiliation: Department of Medicine, University of California San Francisco, San Francisco, California, United States of America.|Department of Epidemiology and Biostatistics, University of California San Francisco, San Francisco, California, United States of America.
authors.forename: Kirsten
authors.initials: K
authors.lastname: Bibbins-Domingo
authors.affiliation: Department of Epidemiology and Biostatistics, University of California San Francisco, San Francisco, California, United States of America.
authors.forename: Feng
authors.initials: F
authors.lastname: Lin
authors.affiliation: Department of Epidemiology and Biostatistics, University of California San Francisco, San Francisco, California, United States of America.
authors.forename: Eric
authors.initials: E
authors.lastname: Vittinghoff
authors.affiliation: Division of Cardiology, Department of Medicine, University of California San Francisco, San Francisco, California, United States of America.
authors.forename: Elyse
authors.initials: E
authors.lastname: Foster
authors.affiliation: First Cardiology Consultants, Ikoyi, Lagos, Nigeria.
authors.forename: Kofo O
authors.initials: KO
authors.lastname: Ogunyankin
authors.affiliation: Division of Cardiology, Department of Medicine, Johns Hopkins Hospital and School of Medicine, Baltimore, Maryland, United States of America.
authors.forename: Joao A
authors.initials: JA
authors.lastname: Lima
authors.affiliation: Division of Epidemiology and Community Health, University of Minnesota, Minneapolis, Minnesota, United States of America.
authors.forename: David R
authors.initials: DR
authors.lastname: Jacobs
authors.affiliation: Department of Medicine, Institute for Human Genetics, University of California San Francisco, San Francisco, California, United States of America.
authors.forename: Donglei
authors.initials: D
authors.lastname: Hu
authors.affiliation: Department of Medicine, University of California San Francisco, San Francisco, California, United States of America.
authors.forename: Esteban G
authors.initials: EG
authors.lastname: Burchard
authors.affiliation: Electrophysiology Section, Division of Cardiology, Department of Medicine, University of California San Francisco, San Francisco, California, United States of America.
authors.forename: Gregory M
authors.initials: GM
authors.lastname: Marcus
mesh_terms: D000293:Adolescent; D000328:Adult; D001281:Atrial Fibrillation / Q000209:etiology*; D044383:Black People; D005260:Female; D006325:Heart Atria / Q000033:anatomy & histology*; D006801:Humans; D008297:Male; D009929:Organ Size / Q000502:physiology; D044465:White People; D055815:Young Adult