Exposure to Cadmium and Diagnosed ADHD in Children Aged 6-14 Years Old

Neurotoxicology. 2026 Nov 13:103603. doi: 10.1016/j.neuro.2026.103603. Online ahead of print.

ABSTRACT

Cadmium, a neurotoxic metal, has been implicated in several childhood neurobehavioral conditions, however; there has been limited and mixed finding with its relationship with ADHD. Most literature utilized validated questionnaires to measure ADHD and/or ADHD-related behaviors and has not reported results utilizing a diagnosis made by a pediatric psychologist. In this study, we recruited children 6-14 years old to assess the association between cadmium exposure and diagnosed ADHD. Cadmium exposure was measured by children’s nail samples and diagnosis of ADHD was made by a pediatric psychologist with over 30 years of expertise in childhood neurodevelopmental conditions. Nail samples were analyzed by Inductively Coupled Plasa Mass Spectrometry. Statistical analysis to assess the relationship between cadmium exposure and ADHD was conducted using multivariable Poisson regression and quartile analysis, adjusted for age, self-reported race, smoking and maternal depression. In our sample of 278 children, 17.3% of children were diagnosed with ADHD. Cadmium concentrations ranged from 0.002 ppm to 2.54 ppm. Poisson regression showed a statistically significant increase in the prevalence ratio of ADHD as cadmium concentration increases. The prevalence of diagnosed ADHD increased by 1.95 times for every one ppm increase in nail cadmium concentration. The fourth quartile of cadmium concentrations were significantly associated with increased prevalence of ADHD. With the limited and mixed findings of past research, this research is a valuable addition to the research on cadmium exposure and ADHD. More robust study designs are needed to determine causality and further investigate this relationship.

PMID:43025658 | DOI:10.1016/j.neuro.2026.103603