Evaluation of cumulative lead dose and longitudinal changes in structural magnetic resonance imaging in former organolead workers

Objective: We evaluated whether tibia lead was associated with longitudinal change in brain volumes and white matter lesions in male former lead workers and population-based controls in whom we have previously reported on the cognitive and structural consequences of cumulative lead dose. Methods: We used linear regression to identify predictors of change in brain volumes and white matter lesion grade scores, using two magnetic resonance imaging scans an average of 5 years apart. Results: On average, total brain volume declined almost 30 cm, predominantly in gray matter. Increasing age at the first magnetic resonance imaging was strongly associated with larger declines in volumes and greater increases in white matter lesion scores. Tibia lead was not associated with change in brain volumes or white matter lesion scores. Conclusions: In former lead workers in whom cumulative lead dose was associated with progressive declines in cognitive function decades after occupational exposure had ended, cumulative lead dose was associated with earlier persistent effects on brain structure but not with additional worsening during 5 years.