Previous studies have shown active brown adipose tissue (BAT) is present in adults and may play important roles in regulating energy homeostasis. However, the majorities of these studies were done in patients undergoing scanning for cancer surveillance, and may not reflect BAT behavior in healthy individuals. In addition, little is known about the ethnic variation in BAT activity, particularly in Chinese adults. Due to the large amount in our cohort, we are able to look at the difference between subjects for cancer surveillance (CS) and subjects for medical check-up (MC), and to clarify the impact of clinical and lifestyle parameters.