Effects of sex on the levels of metals and metalloids in the hair of a group of healthy Spanish adolescents (13 to 16 years old)

Abstract

Human biomonitoring can be a reliable tool to protect the health of the citizens of major urban environments. Human hair may be an invaluable specimen to determine chronic exposure to any environmental contaminant in an individual, especially in the young population. However, different factors including a lack of studies that have established reference values for metals and metalloids (trace elements) in human scalp hair make the use of this matrix controversial. A monitoring study was performed to establish possible normal or tentative reference values of Al, As, Be, Cd, Cr, Cu, Hg, Mn, Pb, Sn, Ti, Tl and Zn in adolescents' (aged 13-16) hair who have lived since birth in Alcalá de Henares, Madrid region (Spain). Strict inclusion criteria were followed to study the effect of sex on the hair metal content, and the levels of the above contaminants were also studied in park topsoils from Alcalá de Henares. Scalp hair samples were collected from 96 healthy adolescents (28 boys and 68 girls), and reference values were calculated following the recommendations of the International Union of Pure and Applied Chemistry. The levels of Cd, Cu, Pb, Sn and Zn in hair of adolescents from Alcalá de Henares show a sex dependency, being significantly higher in female participants. Sex should be a factor taken into account when developing future reference values and hair metal content. Soil metal contamination was not correlated with the levels found in hair. To conclude, the values of metals and metalloids here analysed and discussed could be considered as tentative reference values for Spanish adolescents aged 13-16 years living in the Madrid region, and may be used to identify the level of exposure of adolescents in this Spanish region to the various metals and metalloids.

Trace Metal Profiles of Human Hair and Nail Samples Collected from Urban and Rural Areas of Zonguldak, Turkey

“…No significant difference was found for the remaining metals between men and women in hair. The obtained data are in agreement with earlier studies indicating genderrelated difference of Zn [22][23][24][25] and Ni [26][27][28] in hair. Different metabolism and physiological roles of the elements have been referred as possible explanations for different hair metal content between the two genders [28].…”

Sexually dimorphic metal alterations in childhood obesity are modulated by a complex interplay between inflammation, insulin, and sex hormones

“…As a clarifying example of sex‐driven differences in metal metabolism, it is well‐known that females have a much higher capacity to extrude potentially toxic calcium from their body than males 47 . This could in turn explain why metal contents in hair samples are usually higher in female subjects, plausibly as a protective mechanism to remove metal species from the circulation with the aim of avoiding pathological consequences 48 . Therefore, we propose that sex‐specific hormonal regulation in response to inflammation and hyperinsulinemia could confer female children with obesity a specific defensive mechanism against the harmful effects that circulant metals may have.…”

“…47 This could in turn explain why metal contents in hair samples are usually higher in female subjects, plausibly as a protective mechanism to remove metal species from the circulation with the aim of avoiding pathological consequences. 48 Therefore, we propose that sex-specific hormonal regulation in response to inflammation and hyperinsulinemia could confer female children with obesity a specific defensive mechanism against the harmful effects that circulant metals may have. Although not supported with experimental data, as we solely analyzed blood samples, we hypothesize that this altered metal transport might affect other cellular compartments besides erythrocytes, since disturbances related to inflammation and sex hormones in childhood obesity have a systemic nature.…”

Chemical Elements in Hair and Their Association with Autism Spectrum Disorder: A Comprehensive Systematic Review

“…It is related to the multitude of factors that affect the reference values. It is imperative to follow an appropriate hair washing procedure before analysis into more elements related to the outer surface of the hair [20].…”