Bundle branch block and other cardiovascular disease risk factors: US–Japan comparison

BackgroundLittle is known about the prevalence of bundle branch block (BBB) and its association with other cardiovascular disease (CVD) risk factors in the general population. The present study aims to describe the prevalence and examine this association using data from the US National Health and Nutrition Examination Survey (NHANES-III) and 1990 Japan National Survey on Circulatory Disorders.MethodsA cross-sectional analytical study design was used in the study with a focus on the differences in the prevalence of left and right BBB (LBBB and RBBB) and their relation to other CVD risk factors between American and Japanese people aged ≥ 40 years.Results(1) Age-adjusted prevalences of LBBB per 1000 population were 5.2 and 1.9 for the US and Japan samples (p < 0.001). No significant difference in the prevalence of RBBB was observed between the two population samples (25.3‰ vs. 24.2‰). (2) LBBB and RBBB were significantly associated with several other CVD risk factors. (3) Multivariate logistic analyses indicated that LBBB and RBBB were significantly associated with increased age, SBP, glomerular filtration rate (GFR), and sex and BMI (for RBBB only) in the US sample. Significant relations of LBBB to age, history of stroke and diabetes; and of RBBB to age, sex, total protein and GFR were observed in the Japanese sample.ConclusionThe American sample has significantly higher prevalence of LBBB than the Japanese sample. BBB is strongly associated with several other CVD risk factors, but the strengths of these associations are different between the US and Japan samples.