Background: Near-infrared time-resolved spectroscopy is a non-invasive method that facilitates analysis of human brown adipose tissue (BAT) density. We measured BAT density in middle-aged patients who had type 2 diabetes by this method and examined the relationship using clinical parameters.

Methods: We studied 33 Japanese middle-aged diabetic patients (30 male and 3 female, age 53.8±10.1 years, BMI 25.4±4.5, and HbA1c 7.2±1.1%). Tissue hemoglobin concentration (tHb) of the supraclavicular region was measured using near-infrared time-resolved spectroscopy, and normalized by subcutaneous fat thickness at the measurement sites.

Results: The average tHb concentration was 51.1±17.7 μM and lower than 77.8 μM—the value equivalent to the detection threshold of BAT by standard FDG-PET in young adults. Univariate regression analysis showed that the tHb of the supraclavicular region was inversely correlated with BMI (r = −0.55, p=0.0009), but the tHb of the deltoid region was not (r = 0.04, p = 0.31). Other parameters showing significant correlations with BAT mass included systolic blood pressure (r = −0.47, p = 0.01) and insulin treatment (r=0.45, p=0.01). Multivariate regression analysis suggested that BMI (β=−0.42, p=0.005), systolic blood pressure (β=−0.29, p=0.042), and insulin treatment (β=0.34, p=0.015) independently account for BAT density.

Conclusion: Our findings suggest that BAT density in middle-aged diabetic patients may relate to obesity more closely than previously thought.


H. Waki: Research Support; Self; MSD K.K., Novartis Pharma K.K., Boehringer Ingelheim Pharmaceuticals, Inc., Sanofi K.K., Ono Pharmaceutical Co., Ltd., Kyowa Hakko Kirin Co., Ltd., Takeda PHarmaceutical Co., Ltd.. N. Watanabe: None. S. Fuse: None. Y. Kurosawa: None. T. Yamauchi: Research Support; Self; Novo Nordisk Inc., Daiichi Sankyo Company, Limited, Sanofi, Takeda, Tanabe-Mitsubishi. R. Kime: None. T. Hamaoka: None. T. Kadowaki: Consultant; Self; Novo Nordisk A/S, AstraZeneca, Merck Sharp & Dohme Corp.. Research Support; Self; Kissei Pharmaceutical Co., Ltd., Taisho Pharmaceutical Co., Ltd., Sanofi, Kyowa Hakko Kirin Co., Ltd., Novo Nordisk A/S, Astellas Pharma, Daiichi Sankyo Company, Limited, Takeda, Mitsubishi Tanabe Pharma Corporation, Ono Pharmaceutical Co., Ltd., Merck Sharp & Dohme Corp., Nippon Boehringer Ingelheim Co. Ltd.. Speaker's Bureau; Self; Astellas Pharma, AstraZeneca, Merck Sharp & Dohme Corp., Ono Pharmaceutical Co., Ltd., Takeda, Eli Lilly and Company, Nippon Boehringer Ingelheim Co. Ltd., Novo Nordisk A/S.

Readers may use this article as long as the work is properly cited, the use is educational and not for profit, and the work is not altered. More information is available at