RESULTS	Older men had lower total ( 316 + / - 13 vs. 585 + / - 26 ng/dl , P < 0.00001 ) and free testosterone ( 4 + / - 0.1 vs. 6 + / - 0.3 ng/dl , P < 0.00001 ) and higher SHBG ( 52 + / - 3 vs. 33 + / - 2 nmol/liter , P < 0.00001 ) than younger men at baseline .\