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Fixed FEV1/FVC ratio < 0.7 for identifying airflow limitation: not a good idea in occupational settings - letters.
Occup Environ Med 2012 Mar; 69(3):227
Dr Søyseth and colleagues recently reported an increased prevalence of airflow limitation in workers employed in the Norwegian smelting industry and significant associations with workplace dust exposures.1 The prevalence of airflow limitation was assessed using prebronchodilator spirometry and two measures of airflow limitation: FEV1/FVC ratio < 0.7 and FEV1/FVC ratio < lower limit of normal (LLN). When compared across age categories (< 35, 35-44, > / = 45 years), the prevalence of airflow limitation based on the ratio < 0.7 versus LLN was approximately doubled in the > / = 45 years age categories across all levels of exposure duration (overall approximately 17.6 vs approximately 8.8%). The rate of FEV1 decline was increased for prevalent and incident cases of airflow limitation defined by both criteria, but it would be of interest to see the rates of decline for workers with FEV1/FVC < 0.7 compared with those where the ratio is <LLN and > / = LLN. The authors recommended that "in occupational healthcare settings, FEV1/FVC ratio < 0.7 should be the preferred index for airflow limitation".
Respiratory-system-disorders; Smelters; Smelting; Air-flow; Spirometry; Age-groups; Exposure-assessment; Health-care; Health-care-facilities; Surveillance
Dr. Eva Hnizdo, Division of Respiratory Disease Studies, National Institute for Occupational Health and Safety, Morgantown, WV 26508, USA
Issue of Publication
Occupational and Environmental Medicine
Page last reviewed: September 2, 2020
Content source: National Institute for Occupational Safety and Health Education and Information Division