Fluorosis and its impact on thyroid hormones: a cross-sectional study in Bankura District, West Bengal, India

ABSTRACT

Background: Fluorosis is an important public health problem in India. Fluoride ions can interact with iodide which can leads to abnormal thyroid function.Methods: The present descriptive, community based study was conducted over a period of 1 year and 6 months in the endemic and non-endemic areas of Bankura district with the sample size of 200. High serum fluoride level (≥0.02 mg/L) was also noted in fluorosis endemic areas (39%) with respect to non-endemic areas (3%). Thyroid profiles were investigated among the participants.Results: Hypothyroidism was found to be higher in proportion in endemic regions (34%) with respect to non-endemic regions (20%). The levels of serum TSH, fT4 and fluoride in endemic areas were correlated significantly with non-endemic areas. Fluoride level was found to be in significant positive correlation with TSH level and in negative significant correlation with fT4 and fT3.Conclusions: High fluoride level could produce hypofunctioning of thyroid gland and so hypothyroidism was found to be higher in proportion in fluorosis endemic areas in respect to non-endemic areas.