Exposure to endocrine-disrupting chemicals in utero and thyroid cancer risk in offspring

Abstract

The Article by Kitahara and colleagues1 published in The Lancet Diabetes & Endocrinology is an excellent effort to study the association between maternal health conditions, particularly thyroid status, either before or during pregnancy, and risk of developing thyroid cancer in offspring. Of the risk factors analysed, the strongest associations were found for higher birth weight and congenital hypothyroidism in offspring, maternal diabetes before or during pregnancy, postpartum haemorrhage, maternal hypothyroidism or hyperthyroidism, and goiter. The authors proposed a novel hypothesis in which offspring are at higher risk of developing any form of thyroid cancer later in life if their mothers had hypothyroidism, hyperthyroidism, goiter, or several other health conditions during the most crucial in-utero and perinatal periods.1 Although experimental investigations are needed to prove this hypothesis, no underlying mechanisms have yet been proposed for this novel observation, which is of immense public health importance. Additionally, it is unclear why thyroid cancer was more common in female offspring of mothers who suffered from thyroid disease and associated ailments. Surprisingly, the decades long existence and pervasive exposure to environmentally persistent and ubiquitous industrial chemicals with strong endocrine-disrupting potential was not discussed in the Article. In our opinion, should have been included because a sizeable number of these gestational and early-life health conditions could be linked to exposure to highly hazardous chemicals, such as polychlorinated biphenyls, bisphenol A, phthalates, and pesticides. These chemicals are used in food packaging and day-to-day household and consumer products (including cosmetics and personal-care items) with potential thyroid-hormone-disrupting effects.2