Occupational associations of preserved ratio impaired spirometry (PRISm) in a population-based study

Preserved ratio impaired spirometry (PRISm) has never been characterized in Kazakhstan, and risk factors for this condition remain poorly described. Given that smoking was associated with PRISm, other sources of air pollution, including occupational exposures, surprisingly remained outside the scope of many studies. We, therefore, aimed to compute the prevalence and test the association of exposure to airborne pollutants in the workplace with PRISm in a cross-sectional study.

Subjects (N = 2,275, median age 41 (interquartile range (IQR) 29; 56) years, 54% men) were recruited from the general population in Aktobe, Karaganda, and Kostanay. They completed the questionnaire and underwent spirometry to measure z-scores of forced expiratory volume in 1 s (FEV1) and forced vital capacity (FVC). Exposures in the workplace were assessed based on jobs held throughout a lifetime using a job-exposure matrix (JEM), and the association with PRISm was tested in adjusted logistic regression.

PRISm was confirmed in 12% of participants (95% confidence interval (CI) 10.7; 13.3), with a higher prevalence observed in women (14, 95% CI 11.7; 15.6) compared to men (10, 95% CI 8.8; 12.2). Occupational airborne exposures, including vapor, gas, dust and fume (VGDF), were not associated with PRISm, either as ever-exposure or as cumulative exposure in years. Body mass index [adjusted odds ratio (OR) 1.05 (95% CI 1.02; 1.07)] and the Charlson comorbidity index [adjusted OR 1.28 (95% CI 1.07; 1.54)] were significantly associated with the outcome, after adjusting for sex, smoking, regular exercise, age, and VGDF exposure.

In the current study, occupational airborne chemical exposures, classified using a JEM, showed a non-significant association with PRISm. However, further research with larger sample sizes is needed.