Abstract
Global Lung Function Initiative (GLI) has recently published international reference values for diffusing capacity of the lungs for carbon monoxide (DLCO). Lower limit of normal (LLN), i.e. the 5th percentile, usually defines impaired DLCO. We studied if the GLI LLN for DLCO differs from the LLN in a Swedish population of healthy, never-smoking individuals and how any such differences affect identification of subjects with respiratory burden.
Spirometry, DLCO, chest high-resolution computed tomography and questionnaires were obtained from the first 15 040 participants, aged 50–64 years, of the Swedish CArdioPulmonary bioImage Study (SCAPIS). Both GLI reference values and lambda-mu-sigma method were used to define LLN in asymptomatic never-smokers without respiratory disease (n=4903 whereof 2329 women).
Both SCAPIS median and LLN for DLCO were above the GLI median and LLN (p<0.05). The prevalence of DLCO <GLI LLN (also <SCAPIS LLN) was 3.9%, while the prevalence of DLCO <SCAPIS LLN, but >GLI LLN was 5.7%.
Subjects with DLCO >GLI LLN, but <SCAPIS LLN (n=860) had more emphysema (14.3% versus 4.5%, p<0.001), chronic airflow limitation (8.5% versus 3.9%, p<0.001) and chronic bronchitis (8.3% versus 4.4%, p<0.01) than subjects with normal DLCO (>LLN GLI and >LLN SCAPIS) (n=13 600). No differences were found with regard to physician-diagnosed asthma.
GLI LLN for DLCO is lower than the estimated LLN in Swedish healthy, never-smoking middle-aged adults. Individuals with DLCO above GLI LLN, but below SCAPIS LLN, had to a larger extent an increased respiratory burden. This suggests clinical implications of choosing adequate LLN for studied populations.
Footnotes
This manuscript has recently been accepted for publication in the European Respiratory Journal. It is published here in its accepted form prior to copyediting and typesetting by our production team. After these production processes are complete and the authors have approved the resulting proofs, the article will move to the latest issue of the ERJ online. Please open or download the PDF to view this article.
Conflict of interest: Dr. Malinovschi has nothing to disclose.
Conflict of interest: Dr. Zhou has nothing to disclose.
Conflict of interest: Dr. Bake has nothing to disclose.
Conflict of interest: Dr. Bergström has nothing to disclose.
Conflict of interest: Dr. Blomberg has nothing to disclose.
Conflict of interest: Dr. Brisman has nothing to disclose.
Conflict of interest: Dr. Caidahl has nothing to disclose.
Conflict of interest: Dr. Engström has nothing to disclose.
Conflict of interest: Dr. Eriksson has nothing to disclose.
Conflict of interest: Dr. Frølich has nothing to disclose.
Conflict of interest: Dr. Janson has nothing to disclose.
Conflict of interest: Dr. Jansson has nothing to disclose.
Conflict of interest: Payment 1-2 lectures annually from Boerhinger -Ingelheim concerning fibrosis
Conflict of interest: Dr. Lindberg reports personal fees from Boehringer-Ingelheim, personal fees from AstraZeneca, personal fees from Novartis, personal fees from Active Care, outside the submitted work.
Conflict of interest: Dr. Linder has nothing to disclose.
Conflict of interest: Dr. Mannila has nothing to disclose.
Conflict of interest: Dr. Persson has nothing to disclose.
Conflict of interest: Dr. Sköld has nothing to disclose.
Conflict of interest: Dr. Torén has nothing to disclose.
Conflict of interest: Dr. Ostgren has nothing to disclose.
Conflict of interest: Dr. Wollmer reports grants from Swedish Heart and Lung Foundation, during the conduct of the study; personal fees from Chiesi Pharma, personal fees from AstraZeneca, outside the submitted work; In addition, Dr. Wollmer has a patent Device and method for pulmonary function measurement issued.
Conflict of interest: Dr. Engvall has nothing to disclose.
- Received October 15, 2019.
- Accepted March 26, 2020.
- Copyright ©ERS 2020