The BOLD study’s past and present
The Burden of Obstructive Lung Disease (BOLD) cohort is a large, multinational, prospective study of chronic respira
tory disease. It started with the intention to measure the prevalence, risk factors, and impact of chronic obstructive pulmonary disease (COPD) in different populations around the world. COPD is a common and serious lung condition that causes breathing difficulties, coughing, wheezing, and reduced quality of life. It is estimated that COPD affects around 300 million people worldwide and is a leading cause of death globally.
The BOLD study has been a reference in the study of COPD because of its strengths:
• wide coverage of world regions and ethnic groups;
• large sample of representative population-based data;
• use of a standardised protocol, including the same questionnaires and same model of machine to test lung function, across study sites;
• centralised training and certification of interviewers and spirometry technicians. The quality of the data was monitored throughout the study, and re-training of staff was carried out if necessary;
• high quality of lung function measurements made before and after administration of a bronchodilator, with centralized quality control and assessment of all spirometry curves.
The BOLD cohort is still ongoing and will continue to provide important data and insights for the prevention, diagnosis, and management of COPD. More details about the past and present BOLD cohort can be found on the study’s website and in the profile published in the International Journal of Epidemiology (https://doi.org/10.1093/ije/dyad146).