Occupation and 11-year lung function decline in the HUNT Study.

Background: The association between occupational titles and lung function has mostly been examined through cross-sectional studies. Preventive measures are expected to mitigate adverse effects; hence, updated estimates are necessary.

Aims: To study change in lung function measured by spirometry across occupations.

Methods: This population-based prospective cohort study comprised 5618 working adult participants of the Trøndelag Health Study (HUNT3, 2005-07), Norway. Among these, 3800 individuals (43% men, mean age 42 years, range 20-55) also attended HUNT4 (2017-19). We analysed longitudinal decline in forced expiratory volume in 1 second (FEV1) z-score during the 11-year follow-up by occupation (white-collar workers as reference category), in mixed models, adjusting for age, sex and smoking. We assessed the prevalence of self-reported respiratory symptoms and disease in the working population in HUNT4 (n = 32 124) and HUNT3 (n = 32 070).

Results: Compared with white-collar workers, agricultural workers and 'drivers and mobile plant operators', had larger declines in FEV1z-score during follow-up. In sex-stratified analyses, men defined as agricultural workers and 'drivers and mobile plant operators' had larger declines than white-collar workers. Among women, who were underrepresented in many blue-collar jobs, workers classified as 'machine operators and assemblers' experienced greater declines. In the working population in HUNT4, the prevalence of respiratory symptoms in connection with work was 8%, and lower among white-collar workers (6%) than blue-collar workers (14%).

Conclusions: Although certain workers in Norway remain at risk for occupational lung function decline, there were modest differences between occupations. The findings encourage continuous efforts to implement preventive measures in high-risk jobs.