Association between Across-Shift Spirometric Parameters and Sleep Characteristics in Workers with Inhalational Occupational Exposure

Abstract

Background and Objective: Workplace exposes workers to different hazardous chemicals. In this study, we aimed to assess the changes of pulmonary function test (PFT) parameters as the objective indicator of lung impairment and its association with demographic data and sleep characteristics. Materials and Methods: This cross-sectional study was carried out on 200 male workers of a smelting factory located in Tehran Province, Iran. The respiratory symptoms questionnaire, Pittsburgh Sleep Quality Index (PSQI), Insomnia Severity Index (ISI), and demographic characteristics were recorded for the participants. Participants also underwent spirometry and the related parameters were recorded. Results: A total of 200 iron foundry workers were assessed. All participants were men, and mean ± standard deviation (SD) of age was 39.1 ± 8.9 years ranging from 20 to 65 years. Of 200 workers, 153 (76.5%) were married and 72 (36.0%) were smokers. Among all participants, 131 (65.5%) reported at least one respiratory symptom, and these workers had significantly poorer sleep quality (P = 0.02) and insomnia (P = 0.01). Across-shift change in forced expiratory volume in one second (FEV1) and peak expiratory flow rate (PEFR) of spirometry parameters was significant among participants with clinical insomnia (P = 0.02 and P = 0.04, respectively) and poor sleep quality (P < 0.0001 and P = 0.04, respectively). Conclusion: Results showed a significant cross-shift reduction in PFT values among workers with clinical insomnia or poor sleep quality. Accordingly, evaluation of sleep characteristics along with respiratory symptoms in workers with inhalational occupational exposure is recommended.