Children exposed to lead have altered brain structure and poorer cognitive function in midlife, according to NIEHS-funded research. These lead-related brain changes may increase the risk of neurodegenerative disease, like dementia, in later life.
The study included 564 children who were enrolled in a New Zealand birth cohort in the early 1970s and followed to midlife. The researchers measured child blood lead levels at age 11 years. Using magnetic resonance imaging, they examined participants’ structural brain integrity at age 45 years. They also assessed adult cognitive function and intelligence using a standardized IQ test.
Higher lead exposure in childhood was associated with structural deficits in the middle-aged brain. High child blood lead levels were linked to reduced volumes of gray and white matter in the brain, which are important for learning, memory, and communication between brain regions. Participants with higher blood lead as children also scored lower in IQ tests in midlife. Specifically, for each 5 micrograms per deciliter more lead they carried as children, study participants lost an average of 2 IQ points by age 45.
According to the authors, results suggest that adults exposed to lead as children may be at increased risk of neurodegenerative diseases in later life and reinforce the need for long-term follow-up of lead exposed child cohorts.
Citation: Reuben A, Elliott ML, Abraham WC, Broadbent J, Houts RM, Ireland D, Knodt AR, Poulton R, Ramrakha S, Hariri AR, Caspi A, Moffitt TE. 2020. Association of childhood lead exposure with MRI measurements of structural brain integrity in midlife. JAMA 324(19):1970-1979.