Table 2.

Modifications observed in different adipose tissue depot during aging

Characteristics	Subcutaneous WAT	Visceral WAT	BAT
Adipocyte size	Young: −	Young: −	Young: +
	Middle age: ++	Middle age: ++	Middle age: +/−
	Old age: +	Old age: +	Old age: −
Proportion of the depot	Young: +	Young: −	Young: ++
	Middle age: ++	Middle age: +	Middle age: +
	Old age: −	Old age: ++	Old age: −
Leptin secretion	Young: +	Young: +/−	Young: − (?)
	Middle age: + to ++	Middle age: +	Middle age: +/− (?)
	Old age: ++	Old age: ++	Old age: + (?)
Relative contribution to circulating leptin levels	Young: ++	Young: −	Young: −
	Middle age: +	Middle age: +	Middle age: −
	Old age: −	Old age: ++	Old age: +/− (?)

Note: Question marks indicate that these subjects need to be further investigated. The minus signs represent a small size or amount whereas the plus signs indicate an important (+) to very important (++) size or amount.

Abbreviations: WAT, white adipose tissue; BAT, brown adipose tissue.