Endocrine Abstracts

Objectives: The brain plays a major role in controlling the desire to eat. We performed a meta-analysis to assess the association of dopamine transporter (DAT)/dopamine receptor (DR) availabilities from neuroimaging studies with obesity.

Methods: We performed a systematic search of MEDLINE and EMBASE for English-language publications. Data were extracted from the publications independently by two reviewers. Effect sizes were correlation coefficient between BMI and the availabilities of DR or DAT from both controls and obese subjects. To investigate DR availability ratio of obese subjects to controls, mean DR availabilities and mean BMI of each group were extracted.

Results: 8 (DR) and 3 (DAT) studies including 332 (DR), and 358 (DAT) subjects were eligible for inclusion in this study. DR availabilities were weakly correlated with BMI (correlation coefficient 0.239, 95% confidence interval 0.164~0.311, P<0.001, I²=26.7%). DR availability ratios decrease as the BMI increases in subjects with BMI more than 40kg/m². However, the pooled data did not show the significant association between DAT availabilities and BMI (correlation coefficient 0.0277, 95% confidence interval −0.130~0.184, P=0.732, I²=74.9%).

Conclusions: DR availability was positively correlated with BMI, however, DAT availability was not associated with BMI. DR availability from subjects with BMI of approximately 35 kg/m² was higher than that from controls, however, DR availability from subjects with BMI more than 40 kg/m² was lower than that from controls, which is consistent with the hypothesis of reward deficiency syndrome in severe obesity.