To investigate the effects of aging and gender on brain dopamine and serotonin transporter bindings, we analyzed [(123)I]FP-CIT single-photon emission computed tomography scans of 231 Parkinson's disease (PD) patients and 230 controls. An automated region-of-interest-based method (BRASS automated analysis software) was used for striatal regions and a voxel-based method (Statistical Parametric Mapping software, SPM8) for the entire brain. In controls, aging was associated with a decline of 3.6%-4.6% per decade in striatal binding. Multiple extrastriatal regions also showed age-related declines. In PD patients, age-related declines were only observed in the caudate nuclei, thalamus, olfactory, and cingulate cortices with a comparable rate of decline as that in controls. Female subjects had higher caudate nucleus binding compared with males with a similar near-significant difference in the right putamen. The results demonstrate that the aging effect is limited in PD, which is possibly because of disease-related excess variation, and the results do not support the theory of accelerated aging of the dopaminergic system in PD. Women have higher caudate nucleus dopamine transporter binding compared with men in both normal and degenerated dopamine systems.
Keywords: Aging; Dopamine; Gender; Parkinson's disease; SPECT.
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