Atrial fibrillation and obesity among older Chinese: The Guangzhou Biobank Cohort Study

Abstract

Background: Atrial fibrillation (AF) is the most common form of arrhythmia, and its prevalence is increasing. Few studies have examined its association with obesity as defined by different criteria, particularly in developing countries. We investigated the association between atrial fibrillation (AF) and obesity indices among older Chinese. Methods: We conducted a community-based nested case control study using cross-sectional data of 5882 men and 14,548 women aged 50 or above from Phases I and II (September 2003 to May 2006) of the Guangzhou Biobank Cohort Study (GBCS). AF cases were identified by the 12-lead body surface electrocardiogram. Results: 159 AF cases (65 men and 94 women) were identified from 19,964 participants with ECG records. 9249 participants with other abnormal ECG findings were excluded, resulting in a case control comparison on 159 AF cases and 10,369 controls. After multivariate adjustment, BMI (adjusted odds ratio (OR) 1.06 per kg/m 2, 95% confidence interval (CI) = 1.01-1.11) and waist circumference (adjusted OR 1.02 per cm (1.00-1.04)) were significant risk factors. The adjusted OR per Z-score [(individual value - mean) / standard deviation] for BMI and waist circumference was 1.21 (1.03-1.41) and 1.18 (1.01-1.38) respectively. Conclusions: This is the first report showing that both general and central obesity are associated with increased risk of AF in an Eastern population with much lower level of obesity than in the West. As both AF and obesity are increasing in developing countries, the results should have important public health implications. © 2009 Elsevier Ireland Ltd.