Heavy metals and trace elements in scalp hair samples of children with severe autism spectrum disorder: A case-control study on Jordanian children.

BACKGROUND: Elemental analysis has been increasingly used for biomonitoring heavy metals and trace elements. METHODS: This study monitored the levels of two heavy metals (Al and Pb), and seven trace elements (Macroelements Mg, K, P and Ca; Microelements Zn, Cu, Fe) in scalp hair of 57 children with severe autism spectrum disorder (ASD) and 50 age-matched controls, using Inductively Coupled Plasma Atomic Emission Spectrophotometry (ICP-AES). RESULTS: Compared to controls, significantly higher levels of Al (p =  0.001), Pb (p =  0.001) and K (p =  0.021), with lower levels of Mg and Zn (p = 0.038) were observed for the ASD group. ASD boys had higher levels of Al (p =  0.001), Pb (p =  0.001) and K (p =  0.017) than control boys, while ASD girls had higher Pb levels (p =  0.005) than control girls. The ASD subgroup exposed to passive smokers had higher levels of Al (p =  0.033) and Pb (p =  0.001, and the ASD subgroup not exposed to passive smoke had higher levels of Al (p =  0.011), Pb (p =  0.001), K (p =  0.003); and lower levels of Mg (p =  0.011) than their controls. Other confounding factors and the correlation between these elements were also investigated. CONCLUSION: This data suggests that exposure to Al and Pb, increase intake of K, and decreased intake of magnesium and zinc, may contribute to ASD etiology.