Abstract
Background and Aim Several factors can influence measured lung function over time. The aim of this study was to investigate period and cohort effects on spirometric measures in a large general population sample in Norway during the 20th century, using GLI-2012 equations as a reference.
Methods 36 466 subjects (born 1894–1969) from four cross-sectional surveys conducted between 1965 and 1999 were included, with harmonised data on smoking habits, respiratory symptoms, lung diseases, education, and spirometry. Changes in FEV1 and FVC z-scores in healthy subjects across surveys were explored to investigate period effects. Linear mixed-effects models of FEV1 and FVC z-scores on birth cohort, with survey as random effect, were used to investigate cohort effects, both in subjects of the total population and in healthy ones.
Results Relatively higher FEV1 and FVC z-scores in healthy subjects were found in the first survey (1965–1970) compared to the more recent ones (1988–1999), suggesting period effects. FEV1 and FVC z-scores increased significantly with birth cohort from 1894 to 1935, after adjustment for covariates. A more stable trend of FEV1 and FVC z-scores with birth cohort was evidenced for subjects born more recently (1945–1969).
Conclusions An increase of lung function with year of birth was observed in Norwegian subjects during the first half of the 20th century. The impact of period effects on lung function decreased from 1965 to 1999.
Footnotes
This manuscript has recently been accepted for publication in the ERJ Open Research. 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 ERJOR online. Please open or download the PDF to view this article.
Conflicts of interest: L. Cestelli has nothing to disclose.
Conflicts of interest: A. Johannessen has nothing to disclose.
Conflicts of interest: K. Stavem reports fees from UCB Pharma and MSD, outside the submitted work.
Conflicts of interest: A. Gulsvik has nothing to disclose. R. Nielsen reports funding from AstraZeneca, outside the submitted work.
This is a PDF-only article. Please click on the PDF link above to read it.
- Received June 22, 2022.
- Accepted September 16, 2022.
- Copyright ©The authors 2022
This version is distributed under the terms of the Creative Commons Attribution Non-Commercial Licence 4.0. For commercial reproduction rights and permissions contact permissions{at}ersnet.org
