Prevalence and Factors Associated with High Levels of Aluminum, Arsenic, Cadmium, Lead, and Mercury in Hair Samples of Well-Nourished Thai Children in Bangkok and Perimeters

Abstract

Toxic element exposure increases risk of neurodevelopmental disorders. However, hair element profiles of well-nourished urban resident children were largely unknown. We identified prevalence and the contributing factors of high hair aluminum (Al), arsenic (As), cadmium (Cd), lead (Pb), and mercury (Hg) levels in 111 Thai children (aged 3-7 years old). Most participants were well-nourished with high socioeconomic status. Since ROC curve of hair element data showed inadequate sensitivity for cutoff set-up, US reference hair levels were used to categorize high and low level groups. Nevertheless, compared to the current reference at 5 μg/dL, blood lead cutoff at 2.15 μg/dL provided more consistent results with that of hair lead levels. High As and Pb levels were the first and second most prevalent element, while Al was the element found in highest amount in hair. High hair Al (12% prevalence) levels were associated with being male regardless of age or nutritional status. High hair As levels were associated with living in Bangkok (OR = 6.57) regardless of school type. High hair Pb levels were associated with being under 5 years old and living in Bangkok (OR = 3.06). However, no associations were found between blood Pb, hair Cd, Hg, and tested factors. These findings suggested that under 5-year-old boys living in capital city like Bangkok may be at risk of exposure to multiple toxic elements. Future studies in these children are warranted to identify their exposure sources and proper risk management strategies.

Concentration of selected elements in the hair of Madagascar girls in relation to nutritional status and place of residence

“…There are no studies reporting data on these factors in Malagasy girls to the authors' best knowledge. Confirmed influence of both factors, nutritional status of the girls and place of residence on the accumulation in their hair studied elements is consistent with the previously cited studies that not only environmental pollution, but also the nutritional status and the quality of the diet used, affect the exposure of the human organism to toxic elements (59,66,69,76) . ANOVA analysis showed that neither nutritional status level expressed by Cole index (Factor A) nor place of residence (Factor B) affected the As, Ni, Pb, Sb or Sn concentration in hair samples of the studied girls (Table 4).…”

“…There are no studies reporting data on these factors in Malagasy girls to the authors' best knowledge. Confirmed influence of both factors, nutritional status of the girls and place of residence on the accumulation in their hair studied elements are consistent with the previously cited studies that not only the environmental pollution but also the nutritional status and the quality of the diet used affect the exposure of the human organism to toxic elements (61,68,71,78) .…”

“…This search showed apparently the relationship between the nutritional status and the hair accumulation in the case of Cd. While residence was considered an important factor influencing hair accumulation of Cd in previous studies (68,69) , we revealed nutritional status as a significant factor of this element accumulation in girls' hair. Xue and Ke (2012) sugested that higher Cd concentrations were associated with lower weight gain in animals (70) .…”

“…We hypothesise that in our group, low diet quality and even starvation could cause tissue atrophy and lead to higher Cd accumulation, which is especially fast and effective in the youngest population. It was proved before that reasonable diet and proper nutritional status protect against undesirable Cd effects, but dietary deficiencies of essential elements (with the greatest importance of Fe, Zn, Cu and Ca) and the high share of grain in the diet increase absorption of Cd (68,71) . Deficiency of Fe and other essential micronutrients as well as the diet based on rice grain is a great problem of Malagasy children.…”

Rare Earth Elements Accumulation in the Hair of Malagasy Children and Adolescents in Relation to Their Age and Nutritional Status

“…At this stage of the research, authors may speculate only that a diet poor in protein and bioelements and a diet rich in grains increases the accumulation of REE in the bodies of malnourished children. This effect is observed for heavy metals, especially cadmium [ 30 , 31 , 32 , 33 ]. Malnourished Malagasy children did not consume meat, fish or milk (nutritional interview data).…”