Supraclavicular Brown Adipose Tissue 18F-FDG Uptake and Cardiovascular Disease

Preclinical data suggest a negative correlation between brown adipose tissue (BAT) and the degree of coronary atherosclerosis. We sought to evaluate the relationship between ¹⁸F-FDG uptake in supraclavicular BAT in relation to arterial inflammation and subsequent cardiovascular disease (CVD) events in humans. Methods: Individuals who underwent ¹⁸F-FDG PET/CT for clinical indications but who did not have either cancer or known atherosclerotic disease at the time of imaging were included. A radiologist masked to clinical data measured ¹⁸F-FDG uptake within BAT (in the supraclavicular region) as well as in subcutaneous adipose tissues. Tissue density was evaluated using CT (Hounsfield units). Arterial inflammation was assessed by measuring arterial ¹⁸F-FDG uptake and calculating target-to-background ratio. CVD events were independently adjudicated by masked cardiologists. Thereafter, the relationship between BAT activity and CVD events was evaluated. Results: A total of 443 patients (age, 55 y [44–66 y]; 44% men; body mass index [BMI], 26 [range, 23–31]) were included, and 30 patients experienced a cardiovascular event during a median follow-up of 4 y. BAT activity negatively correlated with arterial inflammation (r = –0.178, P < 0.01), a relationship that persisted after correcting for age and BMI (r = –0.147, P < 0.01). When either high sensitivity or high accuracy thresholds (from receiver-operating curve analyses) were used to define elevated BAT, high BAT was associated with a reduced risk of CVD events (P = 0.048), even after correcting for age (P = 0.037). Conclusion: Our results suggest that increased supraclavicular BAT activity is inversely associated with arterial inflammation, independently of age and BMI. Additionally, increased BAT may be associated with fewer cardiovascular events.

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