Association of obesity and atrial fibrillation among middle-aged and elderly Chinese

Objective: To examine the associations between body mass index (BMI), waist circumference (WC) and risk of atrial fibrillation (AF) in Chinese adults. Design, Subjects and Measurements: A cross-sectional study was conducted to explore the association between obesity and atrial fibrillation among 18 615 Chinese (10 370 females) aged 35 years and above in 2004. AF was defined by electrocardiography and history. Obesity was classified by BMI and WC, including overweight (BMI: 24.0-27.9 kg m(-2); WC: 85.0-94.9 cm for men and 80.0-89.9 cm for women) and obesity (BMI: >= 28.0kg m(-2); WC: >= 95 cm for men and >= 90 cm for women), according to the Chinese Guidelines on Prevention and Treatment of Obesity in Adults. Multivariable logistic regression was used to analyze the association between obesity and AF. Results: Age- and sex-adjusted prevalence of AF (n = 194) was higher with increased BMI, with 0.9% for normal, 1.1% for overweight and 1.6% for obese (P-trend < 0.01) Chinese. Compared with normal BMI, multivariable-adjusted odds ratios (ORs) were 1.2 (95% confidence interval (CI): 0.8-1.7) for overweight BMI and 1.8 (95% CI: 1.2-2.8) for obese BMI (P-trend < 0.01). After excluding known secondary AF (valvular, postoperative and hyperthyroid) and unclassified AF, the corresponding multivariable-adjusted ORs were 1.4 (95% CI: 0.9-2.2) and 2.2 (95% CI: 1.3-3.7) (P-trend < 0.01). The same trends were observed for WC. Multivariable-adjusted OR was 2.6 (95% CI: 1.4-4.6) for participants with both BMI and WC obesity and 1.7 (95% CI: 1.0-2.9) for participants with both BMI and WC overweight in comparison with those with both BMI and WC in the normal range. Conclusion: Obesity, either defined by BMI or WC, was significantly associated with AF among middle-aged and elderly Chinese. International Journal of Obesity (2009) 33, 1318-1325; doi:10.1038/ijo.2009.157; published online 11 August 2009