Attention Deficient/Hyperactivity Disorder (ADHD) in cadmium exposed children living near coal-fired power plants

Background: Coal-fired power plants are the greatest source of electricity, worldwide. Countries like China, India, and South Africa generate more than 80% of their energy from burning coal. Coal emissions contain numerous neurotoxic metals, including cadmium, which is released in large quantities that put children at risk for mental health conditions. Limited and conflicting research exists that explores the relationship between exposure to cadmium and Attention Deficient/Hyperactivity Disorder (ADHD).
Methods: Using a community-based research design, 278 children were enrolled. Parents completed the Child Behaviour Checklist. Any child with a t-score ≥ 60 was given a clinical assessment by a paediatric psychologist. Cadmium exposure was determined from nail samples collected from children and analysed by Inductively coupled plasma mass spectrometry. Logistic regression was used to evaluate the association between cadmium and ADHD.
Results: ADHD prevalence was 18% which is higher than the global prevalence (8%) and the US prevalence (11%). The median concentration of cadmium in nails of children with ADHD was 0.052 ug/g compared to those without ADHD (0.033 ug/g). Children with primary ADHD had significantly higher concentrations of cadmium in their nails (p=0.014). Logistic regression models controlled for sex, race, age, and traffic exposure showed statistically significant associations between ADHD and cadmium.
Conclusions: This study found that children with cadmium exposure were more likely to have ADHD compared to children without cadmium exposure. Furthermore, as cadmium concentrations increased, the number of children diagnosed with ADHD increased. The continued building and use of coal-fired power plants needs to be assessed regarding cadmium exposure and children’s health.

Kristina M. Zierold earned a PhD in environmental health and epidemiology from the University of Illinois Chicago and an MS in chemical engineering from Vanderbilt University. Dr. Zierold is a full professor in the Department of Public Health at the University of Mississippi in the USA. Her research focuses on environmental pollutants and neurodevelopmental and mental health conditions and occupational injury among youth. She is well-published and has had her research funded by the National Institutes of Health, the Centers for Disease Control and Prevention, and several foundations in the USA. Most of her research is community-based.