Abstract

Brown Fat Activation During Acute Cold Exposure: An Asian Perspective

Chinmeng Khoo , Director of Research, Endocrine Division, NUH

It is well known that lean mass correlates with energy expenditure. Brown fat tissue (BAT) activation (18-FDG uptake) has been associated with exposure to low temperature and is lower in individuals with an increase in energy expenditure. In this study, we examined whether brown fat activation might explain the discordance in the fat free mass and energy expenditure. We selected 38 individuals based on the ±1.5SD for the regression line between resting metabolic rate and lean mass. We performed cold stimulation study and use 18-FDG PET-CT to image the brown fat. We found that was no difference in the brown fat volume or activity between the high vs low SD. We concluded that brown fat does not explain the residual observation between resting metabolic rate and lean mass. We proceeded to examine if there is ethnic differences in the brown fat activity. We observed that Chinese were significantly older than Asian-Indians. There was significant difference in the detectable BAT with cold stimulation between Chinese and Asian-Indians (Chinese 31.3% vs Indians 68.8%, x2- test p=0.034). The explanation for this observation is currently not clear.