Concentrations of alkaline earth elements in hair of a sample of Spanish adults aged 20-24 years from the Region of Madrid.

A low intake of alkaline-earth elements (AEEs) has been related with the risk of different syndromes including hypertension. Human hair, despite being controversial sample matrix, could be used as a tool to determine exposure to metals and metalloids and to estimate their burden in the individual. Thus, we have investigated the presence of calcium (Ca), magnesium (Mg), strontium (Sr) and barium (Ba) in scalp hair collected in 37 young adults (20 to 24 yearsold; 28 female and 9 male) from different towns in the Region of Madrid (Spain). Concentrations of AEEs were analysed by ICP-MS following appropriate methodologies. The limits of detection were: Ca (12.49 µg/g), Mg (0.23 µg/g), Sr (85.66 ng/g) and Ba (31.41 ng/g). The concentrations were significantly higher in hair collected from female compared to male participants for all AEEs monitored (Mann-Whitney U test; median values and intequatile range in µg/g): Ca [622.29 (353.69, 972.39) vs. 241.99 (184.16, 535.33); p<0.01), Mg [54.94 (35.17, 91.84) vs. 21.00 (12.36, 28.81); p<0.01], Sr [3.32 (1.74, 5.99) vs.1.19 (0.40, 1.61); p<0.01] and Ba [0.77 (0.43, 1.33) vs. 0.27 (0.15, 0.36); p<0.01]. The lower levels of the relevant AEEs in hair from males might indicate a risk of hypertension in the male young adults monitored from the Region of Madrid. However, more studies would be needed, as higher levels of most of the inorganic elements have been reported in the literature in female adults’ hair. The higher levels observed in this study might be atributed to the diet as the presence of AEEs have been positively correlated with the ingestion frequencies of meat, eggs, vegetables and fruits. Contrarily, we have detected significant higher intake of cereals, eggs and fish in the male participants monitored. Therefore, there would be other potential factors that could play a role in the excretion of these AEEs according to sex that could explain our results but those factors remain unknown at present. Appropriate knowledge of the excretion of inorganic elements in human hair is needed due to the potential clinical significance of hair AEEs as potential marker for risk of hypertension.