Prevalence of first-degree atrioventricular block and the associated risk factors: a cross-sectional study in rural Northeast China

BACKGROUND: First-degree atrioventricular block (AVB) has traditionally been regarded as a benign condition but recent studies have challenged this conception. Prevalence of 1-2% have been reported in developed countries in Asia. However, no epidemiologic studies have established the prevalence of first-degree AVB in developing countries. The aim of the study was to investigate the prevalence of first-degree AVB in rural northeast China and identify the associated risk factors. METHODS: This cross-sectional study was undertaken from September 2017 to May 2018 in rural areas of Liaoning Province. It involved 10,926 participants aged ≥40 years (85.3% of those who were eligible). First-degree AVB was confirmed by at least two independent cardiologists. Risk factors were evaluated using stepwise logistic regression. RESULTS: The prevalence of first-degree AVB was 3.4% (95% confidence interval [CI]: 3.0-3.8%). Males had a higher prevalence than females (5.1% vs. 2.2%, p < 0.001). The regression model involving all participants showed that age (odds ratio [OR]: 1.32; p <0.001), male sex (OR: 1.72; p = 0.001), height (OR: 1.25; p = 0.008), systolic blood pressure (SBP) (OR: 1.15; p = 0.003), triglycerides (TG) (OR: 1.10; p < 0.001), high-density lipoprotein cholesterol (HDL-C) (OR: 0.73; p < 0.001), heart rate (OR: 0.78; p < 0.001), and exercising regularly (OR: 0.73; p = 0.030) were independent risk factors. CONCLUSIONS: First-degree AVB is highly prevalent in rural areas of northeast China. The associated independent risk factors include being male, older, and taller, higher SBP and TG, lower HDL-C and heart rate, and lack of exercise.