[Risk factors associated with chronic obstructive pulmonary disease: a comparison between urban and rural populations...

To determine risk factors associated with the prevalence of chronic obstructive pulmonary disease (COPD) in urban and rural populations in Chengdu.

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.

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.

COPD prevalence is higher in rural areas than in urban Chengdu. Major risk factors of COPD include smoking, coal fuels and BMI.