Objectives To estimate the prevalence of spirometry-defined airflow obstruction among ever-employed US adults.

Methods Data from the 2007 to 2010 National Health and Nutrition Examination Survey (NHANES) for adults 18–79 years with valid spirometry and longest held occupation were analysed. The age-standardised prevalence of spirometry-defined airflow obstruction was estimated overall and by smoking status.

Results Age-standardised prevalence of airflow obstruction was 13.7% (95% CI 12.4% to 15.0%) and was highest in participants aged 60–79 years (17.4%, 95% CI 15.2% to 19.6%), males (14.8%, 95% CI 12.0% to 17.6%), non-Hispanic whites (15.4%, 95% CI 13.8% to 16.7%) and ever smokers (19.1%, 95% CI 16.6% to 21.5%). Age-standardised prevalence of airflow obstruction was >20% for installation, maintenance and repair occupations (p=22.1%, 95% CI 16.5% to 27.8%), and for construction and extraction occupations (20.7%, 95% CI 13.5% to 27.9%).

Conclusions Prevalence of airflow obstruction varied by demographic characteristics and occupational factors with a higher prevalence among ever smokers for most demographic characteristics and occupational factors. Study findings emphasise the importance of monitoring the lung function of workers in occupations with a high prevalence of airflow obstruction.