Association between shift work and levels of thyroid hormones and interleukin-37

Objective. Symptoms of thyroid defects involve sleep disorders, gain or loss of weight, tremors of hand, constipation, dry skin, bradycardia, diarrhea, irregular menses, and hot or cold tolerance. Workers in different professions face different situations that can lead to stress. This study aimed to examine the association between shift work (office or irregular) and thyroid function indicators, interleukin-37 (IL-37) levels, and development of chronic diseases (cardiovascular, diabetes). Methods. The current study comprised three groups: 1) office staff, 2) irregular staff (comprising different jobs), and 3) controls (not working subjects). Eighty-five subjects, aged 30-55 years, were included in the study. Body mass index (BMI) was calculated for each participant. Venous blood was collected and serum levels of triiodothyronine (T3), thyroxine (T4), thyroid-stimulating hormone (TSH), and thyroid peroxidase (TPO) were determined by electrochemiluminescence (ECL) analysis using an automatic immunochemical analyzer Cobas E 411 (Roche Diagnostics, Germany). Serum IL-37 levels were measured using ELISA kit. Results. Serum T3 (p<0.01) and T4 (p<0.001) levels were significantly decreased in both office and irregular shift work groups compared to the controls. The mean T3 levels were higher in subjects with irregular shift work (1.162±0.11 ng/mL) compared to subjects with office shift work (1.14±0.12 ng/mL). Significantly increased TSH and TPO serum levels (p<0.01) were found in both the irregular shift work and office shift work groups compared to the control group. Similarly, IL37 levels were significantly increased in office shift work (294.8±21.05 ng/mL) and irregular shift work subjects (278.0±16.22 ng/mL) (p<0.001) compared to controls (56.5±0.28 ng/mL). Cardiac disease (p<0.01), hypertension (p<0.001), and diabetes (p<0.001) showed significant differences between subjects with office shift work, irregular shift work, and the control group. Conclusion. Elevated levels of IL-37 and TSH in shift workers may serve as biomarkers of the impact of shift work and the workplace on the immunological and hormonal status of employees.