Poster #124 - Level of Metals in Deciduous Teeth and the Development of Children’s Temperament

• In Event: Poster Session 17

Abstract

Concern about the adverse effects of environmental pollutants produced by anthropogenic activities on children’s development has been increasing. The previous literature demonstrates their effects on children’s development such as disease and intellectual functioning (Stewart et al., 2008). However, few studies have examined their effects on children’s temperament. Concerning environmental pollutants, fewer studies have examined the effects of metals on children’s development compared to organic compounds such as polychlorinated biphenyls (PCB).
This study examined the effects of exposure to metals on temperamental development in children during early and middle childhood. Since fetal to infancy is the most vulnerable period for the exposure to environmental pollutants (Berghuis et al., 2015), the level of metal exposure during this period was determined by measuring the concentration of metals in the deciduous teeth enamel of children that was formed during this period.
Of the 935 parents who responded to the early childhood questionnaire, 48 participated in both questionnaire completion and donation of their deciduous primary teeth in middle childhood. The children's ages ranged from 3 to 6 years and 8 to 12 years in early and middle childhood, respectively. The final sample included 25 boys and 23 girls.
The Japanese version of the Children’s Temperament Questionnaire (CBQ) (Kusanagi, 1993) and the Japanese version of the Temperament in Middle Childhood Questionnaire (TMCQ) (Takahashi et al., 2020) were used to measure the children’s temperament in early and middle childhood, respectively. Three factors of the temperament scale (Surgency/Extraversion [SE], Negative Affectivity [NA], and Effortful Control [EC]) were calculated.
Only the enamel of primary deciduous teeth were digested in HNO3, HCl, and HBF4 solutions at 105℃. Concentration of 16 metals, including calcium (Ca), phosphorus (P), sodium (Na), magnesium (Mg), aluminum (Al), potassium (K), manganese (Mn), iron (Fe), copper (Cu), zinc (Zn), arsenic (As), selenium (Se), strontium (Sr), cadmium (Cd), mercury (Hg) and lead (Pb), in the solution were determined using ICP-MS (Agilent 8800 ICP-QQQ) or ICP-AES (ICPE9000 by Shimadzu Corporation). Four samples with insoluble residues in the solution were excluded from the following analysis. Most of the samples were below the limit of quantification for Cu, As, Se, and Hg and were, therefore, excluded from the statistical analysis.
Since the distribution of metal concentration was skewed, the Spearman’s correlation coefficient with temperament factor scales was calculated. Concentrations below the limit of quantification were defined as “0.”
There were significant correlations between Al and ES (ρ = .36) and EC (ρ = .34) of the CBQ, and ES of the TMCQ (ρ = .31), between Zn and EC of the TMCQ (ρ = .30), and between Sr and ES of the CBQ (ρ = .33).
Our results indicated that metal exposure among children during prenatal to early infancy effects the development of their temperament. Additionally, their effect differed depending on the children’s developmental stage.

Authors

• Emiko Kusanagi, Kokugakuin University Hokkaido Junior college
  Presenting Author

• Koichi Nakamura

• Yasutaka Yawaka

• Shoto Suzuki

• Nozomi Takeda

• Nobuko Hoshi, Junior college of Sapporo Otani University

• Yoshinobu Takahashi

• Shing-Jen Chen

• Yusuke Moriguchi, Kyoto University