The Burden of Obstructive Lung Disease (BOLD) study is a comprehensive research project that aims to assess the prevalence and risk factors of chronic obstructive pulmonary disease (COPD) in adults aged 40 and above from different regions worldwide. The study collected spirometry data from over 28,000 participants across 41 sites in Africa, Asia, Europe, North America, the Caribbean, and Oceania. The follow-up study further investigated lung function decline, risk factors, and the relationship between lung function and mortality. The study provides valuable insights into COPD prevalence and risk factors, particularly in low- and middle-income countries. The study data are not freely accessible, but collaboration proposals can be submitted to the project lead. [Extracted from the article]