A comparison of blood metal levels in autism spectrum disorder and unaffected children in Shenzhen of China and factors involved in bioaccumulation of metals

The present study compared blood plasma metals in children with autism spectrum disorder (ASD) with those in unaffected children in Shenzhen (China). Factors associated with the metal bioaccumulation were further investigated. Thirty-four blood samples of children with ASD were collected in a local hospital (Shenzhen Children's Hospital), while those of 38 unaffected children were from a local large public kindergarten, during March to April in 2016. Metal analysis was carried out by inductively coupled plasma-optical emission spectrometry. The results showed that children with ASD had higher (P < 0.01, 0.05) Pb (ASD 31.9 mu g/L, unaffected children 18.6 mu g/L), Hg (3.83, and 1.09 mu g/L), and Cd (0.70 and 0.26 mu g/L) than unaffected children, while essential elements Zn (ASD 4552.0 mu g/L, unaffected children 5118.6 mu g/L), Se (61.7 and 90.6 mu g/L), and Mn (13.5 and 21.4 mu g/L) showed an opposite pattern. Moreover, the children exposed to passive smoking had higher (P < 0.05) Cd (passive smoking 1.08 mu g/L; non-passive smoking 0.22 mu g/L) than those without the exposure. Positive associations were found between levels of Hg or Pb and seafood consumption as well as body mass index (BMI). More future work is needed in order to clarify the association between metal exposure and ASD occurrence in China.