Metal concentrations in hair and cognitive assessment in an adolescent population

The objective of this study was to establish the potential relationship between the levels of various metals in hair and cognitive functions in children living in zones of Tarragona (Catalonia, Spain) with different metal pollution levels. Thirty-nine boys and 61 girls (12-14 yr old) from various schools were selected for the study. The concentrations of cadmium (Cd), chromium (Cr), mercury (Hg), lead (Pb), manganese (Mn), nickel (Ni), and tin (Sn) in scalp hair were determined by inductively coupled plasma- mass spectrometry (ICP-MS). Attention, visuospatial capabilities, and abstract reasoning were assessed as indicators of cognitive impairment. Three categories of attention were defined: low, medium, and high. A significant negative correlation (p=0.019) between Pb levels in hair and attention was observed. Significant differences between Pb levels in hair in low- and medium-performance groups and those in the high-performance group were also found. Moreover, a positive correlation (p=0.048) between Hg hair concentrations and visuospatial capabilities was also noted.