Methylmercury Exposure and Developmental Outcomes in Tohoku Study of Child Development at 18 Months of Age.

Nozomi Tatsuta,Katsuyuki Murata,Hiroshi Satoh,Kunihiko Nakai,Mineshi Sakamoto

doi:10.3390/toxics6030049

Nozomi Tatsuta, Katsuyuki Murata + Show 3 more

Open Access

https://doi.org/10.3390/toxics6030049

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Abstract

Seafood is an important component in a healthy diet and may contain methylmercury or other contaminants. It is important to recognize the risks and benefits of consuming seafood. A longitudinal prospective birth cohort study has been conducted to clarify the effects of neurotoxicants on child development—the Tohoku Study of Child Development (TSCD) in Japan. TSCD comprises two cohorts; a polychlorinated biphenyls (PCB) cohort (urban area) and a methylmercury cohort (coastal area). Our previous results from the coastal area showed prenatal methylmercury exposure affected psychomotor development in 18-month-olds, and boys appear to be more vulnerable to the exposure than girls. In this report, we have added the urban area cohort and we reanalyzed the impact of prenatal exposure to methylmercury, which gave the same results as before. These findings suggest prenatal exposure to low levels methylmercury may have adverse effects on child development, especially in boys.

Highlights

Seafood is a good source of protein and various essential nutrients including n-3 polyunsaturated fatty acids (n-3 PUFAs), selenium, iodine, and vitamin D, whereas it is low in fatty acids
We previously reported that the psychomotor development in 18-month-old children of the coastal area was significantly correlated with cord-blood total mercury (THg) only in the boys, and that this association remained significant after adjustment for possible confounders, including maternal-plasma docosahexaenoic acid (DHA) and cord-plasma selenium [22]
In the urban area cohort (PCB cohort) with 599 registered mothers, cord blood samples were collected from 562 participants (93.8%), maternal hair samples at parturition were collected from 595 participants (99.3%), and the food frequency questionnaire (FFQ) was administered to 598 participants (99.9%)

Summary

Introduction

Seafood is a good source of protein and various essential nutrients including n-3 polyunsaturated fatty acids (n-3 PUFAs), selenium, iodine, and vitamin D, whereas it is low in fatty acids. N-3 PUFAs, such as docosahexaenoic acid (DHA), are important because these fats are difficult to get in sufficient amounts from other food items but are highly beneficial for maternal and fetal health because of their critical role in proper brain development and function [1,2]. Seafood contains several toxic chemicals like methylmercury and polychlorinated biphenyls (PCB). Human exposure to methylmercury and PCB occurs mainly from the intake of seafood [5].

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