Optimizing the methodology for measuring supraclavicular skin temperature using infrared thermography; implications for measuring brown adipose tissue activity in humans

The discovery of brown adipose tissue (BAT) in adults has sparked interest in its role as a therapeutic target in metabolic disorders. Infrared thermography is a promising way to quantify BAT; however, a standardized methodology has not been established. This study aims to establish a standardized and reproducible protocol to measure thermal response to cold in the supraclavicular area using thermographic imaging. In Phase 1, we compared the thermal response to 12 degrees C cold after acclimation at either 32 degrees C or room temperature using thermographic imaging. Repeatability of the 32 degrees C acclimation trial was studied in a second group in Phase 2. Phase 1 included 28 men (mean age 23.9 +/- 5.9 y; mean BMI 25.2 +/- 3.9 kg/m(2)) and Phase 2 included 14 men (mean age 20.9 +/- 2.4 y; mean BMI 23.6 +/- 3.1 kg/m(2)). The thermal response was greater after 32 degrees C than after room temperature acclimation (0.22 +/- 0.19 vs 0.13 +/- 0.17 degrees C, p = 0.05), was not related to outdoor temperature (r = -0.35, p = 0.07), did not correlate with supraclavicular fat (r = -0.26, p = 0.21) measured with dual-energy x-ray absorptiometry and was repeatable [ICC 0.69 (0.14-0.72)]. Acclimation at 32 degrees C followed by cold generates a reproducible change in supraclavicular skin temperature measurable by thermal imaging that may be indicative of BAT metabolic activity.