Prevalence,risk factors and underdiagnosis of asthma and wheezing in adults 40 years and older: A population-based study

Objective: There are differences in the prevalence and risk factors of asthma around the world. The epidemiological situation of adults 40 years and older is not well established. Our aim was to determine the prevalence, underdiagnosis and risk factors of asthma and wheezing in adults in Colombia. Methods: A cross-sectional, population-based study including 5539 subjects from 40 to 93 years selected by a probabilistic sampling technique in five cities was conducted. Measurements: respiratory symptoms and risk factors questionnaire and spirometry. Definitions: (a) Wheezing: Affirmative answer to the question “have you ever had two or more attacks of “wheezes” causing you to feel short of breath?” (b) Asthma: Wheezing definition and FEV₁/FVC post-bronchodilator?≥?70%. (c) Underdiagnosis: Asthma definition without a physician-diagnosis. Logistic regression was used for exploring risk factors. Results: Prevalence of asthma was 9.0% (95% CI: 8.3-9.8) and wheezing 11.9% (95% CI: 11.0-12.8). Asthma underdiagnosis was 69.9% and increased to 79.0% in subjects 64 years or older. The risk factors related to asthma and/or wheezing were: living in Bogota or Medellin, female gender, first degree relative with asthma, respiratory disease before 16 years of age, obesity, no education, indoor wood smoke exposure and occupational exposure to dust particles, gases or fumes. Conclusion: We described the epidemiologic situation of asthma in adults 40 years and older in Colombia. In addition to some recognized risk factors, our data supports the association of indoor wood smoke and occupational exposures with asthma and wheezing. Underdiagnosis of asthma in adults was high, particularly in older subjects.