Extract
Using a very large number of predominantly Chinese nonsmoking females aged 30–79 years, Smith et al. [1] studied the relationship between airflow obstruction, household air pollution, household income, educational level and prior tuberculosis. They defined airflow obstruction as a ratio of forced expiratory volume in 1 s (FEV1) to forced vital capacity (FVC) of <0.7 or <5th percentile, and graded the severity of respiratory impairment using FEV1 80% of predicted as a cut-off point, according to Global Lung Function Initiative 2012 prediction equations [2]. There are two fundamental problems with these criteria that affect the interpretation of their findings.
Abstract
Use of fixed ratio FEV1/FVC and % pred FEV1 cut-off points causes misclassification due to age bias http://ow.ly/Cr9xx
Acknowledgements
The authors thank W. Dejsomritrutai (Dept of Medicine, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok, Thailand), M.S.M. Ip (Dept of Medicine, The University of Hong Kong, Pokfulam, Hong Kong, China), W-H. Pan (Institute of Medical Sciences, Academica Sinica, Taipei, Taiwan), Z. Zhang (Dept of Occupational Health, School of Public Health, Harbin Medical University, Harbin, China) and J.P. Zheng (Guangzhou Institute of Respiratory Disease, State Key Laboratory of Respiratory Disease, Guangzhou, China) for permission to use the data on healthy nonsmoking East Asian females.
Footnotes
Conflict of interest: None declared.
- Received July 9, 2014.
- Accepted July 30, 2014.
- Copyright ©ERS 2015