Brown adipose tissue fatty acid metabolism does not predict changes in obesity at 4-year follow-up

Abstract

Brown adipose tissue (BAT) activity is associated with low obesity and higher insulin sensitivity in cross-sectional studies. No follow-up studies have been done to examine the association to upcoming metabolic health. The aim of this study is to examine whether there is a link with the white adipose tissue mass gain and distribution change in respect to the metabolic activity of the brown adipose tissue reported in the base-line. The hypothesis set in the origin was that the BAT activity in baseline would re-duce the gain of WAT over time and so behave like a conserving factor to WAT mass gain.

The inspiration to this study was set up by the current global health issues we are fac-ing. The burden of obesity induced disease and disability are growing while no exten-sive measures to prevent it has succeeded (Dixon, 2010). The study cohort consisted of 17 (M/F 6/11) healthy subjects that participated the baseline PET imaging and baseline and follow-up MR imaging. Blood tests such as serum total cholesterol, HDL-cholesterol, LDL-cholesterol and triglycerides were col-lected (n=13). Insulin sensitivity was measured with euglycemic clamp M-value calcu-lation (n=11) and oral glucose tolerance testing (n=13).

As a result, the baseline BAT activity had no correlation to WAT volume gain nor clinically relevantly to any other cardiovascular risk factor. Controversially to the hy-pothesis the low BAT activity subgroup seemed to have higher insulin sensitivity than in the baseline as in the high BAT activity subgroup the M-value did not differ from baseline.