Determinants of iron accumulation in the normal aging brain

Abstract In a recent postmortem study, R2 * relaxometry in gray matter of the brain has been validated as a non-invasive measure for iron content in brain tissue. Iron accumulation in the normal aging brain is a common finding and relates to brain maturation and degeneration. The goal of this study was to assess the determinants of iron accumulation during brain aging. The study cohort consisted of 314 healthy community-dwelling participants of the Austrian Stroke Prevention Study. Their age ranged from 38-82 years. Quantitative magnetic resonance imaging was performed on 3T and included R2 * mapping, based on a 3D multi-echo gradient echo sequence. The median of R2 * values was measured in all gray matter regions, which were segmented automatically using FreeSurfer. We investigated 25 possible determinants for cerebral iron deposition. These included demographics, brain volume, lifestyle factors, cerebrovascular risk factors, serum levels of iron and single nucleotide polymorphisms related to iron regulating genes (rs1800562, rs3811647, rs1799945, and rs1049296). The body mass index was significantly related to R2 * in 15/32 analyzed brain regions with the strongest correlations found in the amygdala (p=0.0091), medial temporal lobe (p=0.0002) and hippocampus (p=