Correlation between body mass index and striatal dopamine transporter availability in healthy volunteers--a SPECT study

Recent lines of research suggest that, in addition to hypothalamic sites, the striatum dopaminergic system may be a target for regulating homeostasis that may be represented by the body mass index (BMI). Although it has been reported that the striatal dopamine receptor (DRD2) availability of very obese individuals was reduced in proportion to their BMI, the correlation between the striatal dopamine system and the BMI in healthy individuals remains unclear. To investigate this relationship, the striatal dopamine transporter (DAT) availability of 50 healthy volunteers was measured using single position emission computational topography (SPECT) and [99mTc]-TRODAT-1. The serum levels of sugar, C-peptide, insulin, glycosylated hemoglobin and leptin were measured. Our results showed that age and the BMI are significantly negatively associated with the striatal DAT availability. Moreover, BMI was the only significant predictor for striatal DAT availability. These results suggest that the striatal dopamine system may be involved in body mass index regulation. Thus, molecular imaging studies measuring the striatal DAT availability should consider the BMI, rather than age, as a covariant.