Night Shift Working Is Associated With an Increased Risk of Thyroid Nodules.

Objectives: To study thyroid alterations in health care workers according to their working status.

Methods: We performed a retrospective study including 299 hospital employers who underwent in 2016 a periodic health surveillance checks in the Service of Occupational Medicine. According to the working status (rotating night-shift working [no. 160] vs day-working [no. 139]), we divided participant's clinical, anthropometric, and thyroid echographic characteristics.

Results: Respect to day workers, rotating night-shift workers were slightly older and more frequently male whereas had similar thyroid stimulating hormone, Ft3, Ft4 levels, and autoimmunity (anti-TPO levels more than 30). Univariate and multivariate regression analysis revealed that rotating night shift work is associated to a significantly increased number of thyroid nodules.

Conclusions: This retrospective report suggests that the alteration in the molecular clocks typical of rotating night-shift workers harbors a higher risk of thyroid nodule development compared with diurnal workers. This novel result deserves replication in larger cohorts since thyroid nodules not rarely can represent thyroid cancers.