Observational · 2021

Association of Childhood Lead Exposure With MRI Measurements of Structural Brain Integrity in Midlife.

A Reuben, ML Elliott, WC Abraham, J Broadbent, RM Houts, D Ireland, AR Knodt, R Poulton. JAMA.

IMPORTANCE: Childhood lead exposure has been linked to disrupted brain development, but long-term consequences for structural brain integrity are unknown. OBJECTIVE: To test the hypothesis that childhood lead exposure is associated with magnetic resonance imaging (MRI) measurements of lower structural integrity of the brain in midlife. DESIGN, SETTING, AND PARTICIPANTS: The Dunedin Study followed a population-representative 1972-1973 birth cohort in New Zealand (N = 564 analytic sample) to age 45 years (until April 2019). EXPOSURES: Childhood blood lead levels measured at age 11 years. MAIN OUTCOMES AND MEASURES: Structural brain integrity at age 45 years assessed via MRI (primary outcomes): gray matter (cortical thickness, surface area, hippocampal volume), white matter (white matter hyperintensities, fractional anisotropy [theoretical range, 0 {diffusion is perfectly isotropic} to 100 {diffusion is perfectly anisotropic}]), and the Brain Age Gap Estimation (BrainAGE), a composite index of the gap between chronological age and a machine learning algorithm-estimated brain age (0 indicates a brain age equivalent to chronological age; positive and negative values represent an older and younger brain age, respectively). Cognitive function at age 45 years was assessed objectively via the Wechsler Adult Intelligence Scale IV (IQ range, 40-160, standardized to a mean of 100 [SD, 15]) and subjectively via informant and self-reports (z-score units; scale mean, 0 [SD, 1]). RESULTS: Of 1037 original participants, 997 were alive at age 45 years, of whom 564 (57%) had received lead testing at age 11 years (302 [54%] male) (median follow-up, 34 [interquartile range, 33.7-34.7] years). Mean blood lead level at age 11 years was 10.99 (SD, 4.63) μg/dL. After adjusting for covariates, each 5-μg/dL higher childhood blood lead level was significantly associated with 1.19-cm2 smaller cortical surface area (95% CI, -2.35 to -0.02 cm2; P = .05), 0.

Open sourcedoi:10.1001/jama.2020.19998PMID 33201203