This worldwide study sought to determine the prevalence of chronic obstructive pulmonary disease (COPD) and its risk factors and investigate variation across countries by age, sex, and smoking status. A total of 9,425 participants completed postbronchodilator spirometry testing plus questionnaires about respiratory symptoms, health status, and exposure to COPD risk factors. COPD prevalence estimates based on the Global Initiative for Chronic Obstructive Lung Disease staging criteria were adjusted for the target population. Overall, 10.1% had stage II or higher COPD; gender-specific rates were 11· 8% for men and 8·5% for women. Odds ratios (ORs) for 10-year age increments did not vary greatly across sites and for women and men. The overall pooled estimate was 1· 94 (95% CI 1· 80 to 2·1 0) per 10-year increment. Sitespecific pack-year ORs varied significantly in women (pooled OR=1· 28, 95% CI 1·1 5 to 1· 42), but not in men (1·1 6, 1·1 2 to 1· 21). The authors note that while age and smoking are recognised as strong contributors to COPD, they fail to fully explain variations in disease prevalence; local public health officials must better appreciate what other factors contribute to COPD, in order to develop appropriate, region-specific primary and secondary prevention policies.
