METHODS	To examine the effects of age on the estrogen-stress interaction , we performed a median split on age and created four groups of participants : younger-placebo ( mean age : 55.5 years ) , younger-E2 ( mean age : 55.5 years ) , older-placebo ( mean age : 73.0 years ) , and older-E2 ( mean age : 76.8 years ) .\