Thyroid function in nurses: the influence of povidone-iodine hand washing and gargling.

The effect of povidone-iodine (PVP-I) hand washing and gargling on thyroid function was assessed. In 16 nurses using PVP-I products and 16 control subjects, serum inorganic iodine levels and thyroid functions were investigated. The status of PVP-I use was also surveyed in the nurses. Clinical symptoms considered to be attributable to thyroid dysfunctions were seen in none of the subjects, nor was a goiter observed in any of the subjects. In nurses, serum inorganic iodine levels were slightly increased as compared to those in the control subjects, although the difference was not significant. The iodine incorporated during working hours of nurses appears to be attributable to gargling rather than to hand washing. The long-term use of PVP-I for gargling should be avoided by (1) people with a high risk of developing thyroid dysfunction due to the excessive intake of iodine, (2) pregnant women and (3) breast-feeding mothers.