Exploring chronotype, sleep patterns, and health in petrochemical shift workers

OBJECTIVE: Chronotype is a personal characteristic affecting an individual's adaptability to shift work. The present study aimed to investigate the relationship between chronotype, shift work-related health disorders and sleep quality in shift workers in the petrochemical industry in southern Iran. DESIGN: This was a cross-sectional study. SITE: The study was conducted in a petrochemical complex located in southern Iran. PARTICIPANTS: 250 male shift workers with at least five years of shift work experience, no major physical or mental health issues, and no use of alcohol, drugs, or sleep medications. INTERVENTIONS: No interventions were applied, as this was an observational cross-sectional study. MAIN MEASUREMENTS: Data were collected using the Shift Work Impact on Health and Social Disorders (SOS) Questionnaire, the Pittsburgh Sleep Quality Index (PSQI), the Morningness-Eveningness Questionnaire (MEQ), and the Cognitive Failure Questionnaire. RESULTS: The prevalence of musculoskeletal, gastrointestinal, and cardiovascular disorders was significantly higher in morning types than evening types (p<0.05). Cognitive failures and sleep quality also differed significantly between the two groups (p<0.05). CONCLUSIONS: Evening-type individuals showed higher adaptability to shift work and lower vulnerability to negative consequences. Circadian typology should be considered when assigning workers to shifts, especially for sensitive jobs.