Background: Many important clinical features of bronchiectasis have been reported. However, the factors were evaluated using a specific disease cohort. Thus, clinical factors associated with bronchiectasis have not been well assessed in comparison to the general population. The aim of this study was to evaluate the factors associated with bronchiectasis using a national representative database.

Methods: We conducted a cross-sectional study using data from the Korean National Health and Nutrition Examination Survey 2007-2009. To evaluate factors associated with bronchiectasis, a multivariable logistic analysis was used with adjustment for demographic and socioeconomic factors.

Results: In the present study, the prevalence of bronchiectasis was 0.4%. Compared with subjects without bronchiectasis, subjects with bronchiectasis were older (55.1 vs. 44.4 years, P<0.001) and had lower body mass index (BMI) (23.2 vs. 24.2 kg/m², P<0.001). The proportions of low family income (70.5% vs. 40.2%, P<0.001) and low educational level (less than high school) (85.3% vs. 70.6%, P=0.041) were higher in subjects with bronchiectasis than in subjects without bronchiectasis. Regarding comorbidities, subjects with bronchiectasis were more likely to have asthma (17.8% vs. 2.9%, P<0.001), previous history of pulmonary tuberculosis (TB) (43.5% vs. 5.0%, P<0.001), osteoporosis (19.1% vs. 7.8%, P=0.002), and depression (9.3% vs. 3.0%, P=0.015) compared with subjects without bronchiectasis. In addition, subjects with bronchiectasis had more respiratory symptoms and poorer quality of life measured using the EuroQoL five dimensions questionnaire (EQ-5D) index (0.87 vs. 0.93, P<0.001) than subjects without bronchiectasis. In multivariable logistic regression analysis, low family income (adjusted odds ratio, OR =3.83, 95% confidence interval, CI: 1.46-10.03), asthma (adjusted OR =3.73, 95% CI: 1.29-10.79), pulmonary TB (adjusted OR =7.88, 95% CI: 2.65-23.39), and the presence of airflow limitation (adjusted OR =2.98, 95% CI: 1.01-8.98) were independently associated with bronchiectasis.

Conclusions: Subjects with bronchiectasis suffered from more respiratory symptoms with limited physical activity and poorer quality of life than the general population. Factors independently associated with bronchiectasis were lower family income and comorbid pulmonary conditions, such as previous pulmonary TB, asthma, and airflow limitation.