Objective: To determine risk factors associated with the prevalence of chronic obstructive pulmonary disease (COPD) in urban and rural populations in Chengdu.
Methods: A multistage random cluster sampling method was adopted to select participants from four communities in Chengdu. All residents aged 40-70 yr. were eligible to participate in this study, which involved a questionnaire survey, physical examination and portable spirometry. Those with airflow limitations were also given post-bronchodilator testing 15 min after inhalation of a dose of 200 microg salbutamol. We defined a forced expiratory volume in one second/forced vital capacity (FEV1/FVC) of less than 70% as COPD. Logistic regression models were performed to identify risk factors of COPD.
Results: Of a total of 1931 eligible participants, 1579 (81.77%) completed the questionnaire and spirometry. About 8.35% were identified with COPD: 7.69% in urban vs. 12.37% in rural (P<0.05). The prevalence of COPD increased with age (P<0.05) in the male and total populations. Rural COPD patients had a higher level of smoking rate and use of coal as fuel for cooking than their urban counterparts (P<0.05). But rural COPD patients had a lower level of BMI, waist circumference, literacy, and average household income per capita than their urban counterparts (P<0.05). The multivariate analysis showed that tobacco smoking index (pack-year), education, age and BMI were predictors of COPD for male patients; whereas, coal fuel usage, income and BMI were predictors of COPD for female patients.
Conclusion: COPD prevalence is higher in rural areas than in urban Chengdu. Major risk factors of COPD include smoking, coal fuels and BMI.