Author Contributions: Dr Goadsby had full access to all of the data in the study and takes responsibility for the integrity of the data and the accuracy of the data analysis.
Study concept and design: Cohen, Goadsby.
Acquisition of data: Cohen.
Analysis and interpretation of data: Cohen, Burns, Goadsby.
Drafting of the manuscript: Cohen, Burns, Goadsby.
Critical revision of the manuscript for important intellectual content: Goadsby.
Statistical analysis: Cohen, Goadsby.
Obtained funding: Goadsby.
Administrative, technical, or material support: Burns.
Study supervision: Goadsby.
Financial Disclosures: None reported.
Funding/Support: The trial was jointly sponsored by University College London and BOC Limited (now Linde Gases, Priestley Road, Guildford, Surrey, UK), who supplied the cylinders and the masks.
Role of the Sponsor: BOC (now Linde) gases initially supplied blinded materials and handled logistics of the cylinder delivery, assuming the role of sponsorship from a regulatory viewpoint and providing some administrative costs during the study. Dr Goadsby has provided advisory board advice to Linde and Air Products about cluster headache and its treatment, particularly the use of oxygen.
Previous Presentation: The data were presented in preliminary format at the XIVth International Headache Congress (Stockholm, June 2007).
Additional Contributions: We thank the Organisation for Understanding Cluster Headache (OUCH-UK) for assistance with recruitment of participants and M. S. Matharu, MRCP, for assistance with the initiation of the study, for which he received no compensation.