Hypothyroidism and perchlorate : an ecological study of hypothyroidism in the Maltese Islands

Abstract

BACKGROUND: One of the lesser-known causes of hypothyroidism is perchlorate exposure, a by-product of fireworks. Recent studies in the Maltese islands showed increased concentration of perchlorate in dust fall, leading to public concerns about its health effects. This study aims to examine the hypothyroidism trends in the resident Maltese population and assess for a link with perchlorate exposure.

METHODS: A retrospective ecological study using laboratory and population data was carried out to calculate the crude and direct age-standardised incidence rates of hypothyroidism in the resident population.

RESULTS: Significantly lower overall age-standardised incidence rates for hypothyroidism were found in the region of Gozo; however no clearly discernible geographical pattern of hypothyroidism with clear potential link to perchlorate exposure was found.

CONCLUSION: The lower hypothyroid incidence rates in Gozo warrant a comparative study to establish whether this difference is attributable to differing levels of perchlorate exposure from different scale of firework use.