TABLE 2.
Prevalence of cold-activated BAT in adult humans
| Summer | Autumn | Winter | ||
|---|---|---|---|---|
| Outdoor temperature (°C) | 21.3 (19.6–28.3) | 11.7 (7.6–16.1) | −1.6 | (−5.2 to 1.8) |
| n | 8 | 8 | 31 | 24 |
| Age (years) | 23–31 | 23–32 | 23–35 | 38–65 |
| Prevalence | ||||
| Total | 2/8 (0/1) | 3/8 (0/3) | 16/31 (0/4) | 2/24 |
| Male subjects | 1/5 | 2/6 (0/2) | 8/19 (0/3) | 2/12 |
| Female subjects | 1/3 (0/1) | 1/2 (0/1) | 8/12 (0/1) | 0/12 |
Data are mean outdoor temperature (range) or n apparent FDG uptake into BAT (adipose tissue in the supraclavicular region)/total n. During a 7-month period from August of 2006 to the following March, a total of 71 FDG-PET/CT examinations were conducted under the 2-h cold condition for 56 healthy volunteer subjects as in Fig. 1A. Some (the number in parentheses) underwent the examination again under the warm condition as in Fig. 1B 2 weeks after that under the cold condition. Summer: 29 August to 28 September 2006. Autumn: 5 October to 19 October 2006. Winter: 29 January to 6 March 2007.