Association between urinary toxic and essential metals exposure and autism in children

Autism has a multifactorial origin, with genetic factors playing a significant role, while various environmental factors, including early exposure to toxic or essential metals, have been associated with an increased likelihood in children. The current study analysed the association between 15 different essential and heavy metals and autism among Spanish school children. Urine samples from a total of 108 children (autism group: N = 42; non-autism group: N = 66) between the ages of 5–16 years were analysed. Logistic regressions, adjusted for sex, age, BMI, SES, and diet quality, were performed using a categorical comparison of metal concentrations in quartiles, with the first quartile as a reference. Significant associations were found in the fourth quartile for copper (Cu) (aOR 9.45; CI: 1.89–48.02), third quartile for lead (Pb) (aOR 5.59; CI 1.36–22.94) and in the 75th percentile for manganese (Mn) (aOR 12.50; CI 3.27–47.72). Furthermore, Mn exposure was associated with more pronounced differences in social cognition, as measured by the Social Responsiveness Scale-2nd edition ( β = 22.04, p = .038). However, no significant associations were found with other essential or heavy metals. This study provides significant insights into the association between metal exposure and autism in school-aged children, emphasising the need for further research to better understand and mitigate the impact of environmental influences on children’s health and development. • A significant association was found between exposure to Cu, Mn and Pb and autism. • Specifically, high Mn exposure was associated with poorer social cognition scores. • The study emphasises metal exposure as a potential risk factor for autism in school-aged children.