Incidence of and Risk Factors for Bundle Branch Block in Adults older than 40 years

ABSTRACT

BACKGROUND: In the general population, the incidence of bundle branch block (BBB) is relatively low, and its effects on long-term prognosis have not been established. Previous studies on the incidence and correlation of BBB to clinical factors have produced conflicting results. However, the incidence of BBB was strongly related to age. This study aimed to describe the incidence of and risk factors for BBB in Korea. METHODS: In this study, 14, 540 adults (male 6, 573/female 7, 967) > or=40 years old received screening tests for general health between April and December 2000. Participants answered questionnaires and underwent examinations, which included blood pressure, electrocardiogram (ECG), total cholesterol and fasting glucose. The data analysis was performed using SPSS 10.0 for windows. RESULTS: The incidences of complete right bundle branch block (CRBBB) were 1.5 and 2.9% in people older than 40 and 65 years, respectively. Approximately 38.0% of individuals with CRBBB were older than 65 years. The incidence of CRBBB was higher in men than women at all age groups was highest in those aged 75-79 years. Males, advancing age (> or=65 years), hypertension and diabetes mellitus (DM) were associated with an increased risk of CRBBB. The incidences of complete left bundle branch block (LBBB) and bifascicular bundle branch block (BBBB) were 0.1 and 0.08% and 0.3 and 0.2% in those older than 40 and 65 years, respectively. Approximately 71.4 and 58.3% of individuals with LBBB and BBBB, respectively, were older than 65 years. Advancing age and cardiac disease were associated with an increased risk of LBBB. Advancing age was associated with an increased risk of BBBB. The most potent risk factor for BBB in this study was advancing age. CONCLUSION: The incidences of BBB were 1.7 and 3.4% in those older than 40 and 65 years respectively. Bundle branch block correlates strongly with age, and is common in the older ages groups. These findings support the theory that bundle branch block is a marker of slowly progressing degenerative diseases.