42632
document
Conjugated equine estrogen influence on mammographic density in postmenopausal women in a substudy of the women 's health initiative randomized trial . PURPOSE Increased mammographic density is associated with increased breast cancer risk and reduced sensitivity of screening mammography and is related to hormone exposure . However , the effects of conjugated equine estrogens ( CEEs ) alone on mammographic density in diverse racial/ethnic populations are not established . We examined the effect of CEE alone on mammographic density in a subsample of the Women 's Health Initiative ( WHI ) clinical trial participants . PATIENTS AND METHODS In the WHI trial , women were randomly assigned to daily CEE 0.625 mg or placebo . The effect of CEE on mammographic percent density was determined over 1 and 2 years in a stratified random sample of 435 racially and ethnically diverse participants from 15 of 40 WHI clinics . RESULTS Use of CEE resulted in mean increase in mammographic percent density of 1.6 percentage points ( 95 % CI , 0.8 to 2.4 ) at year 1 compared with a mean decrease of 1.0 percentage point ( 95 % CI , -1.7 to -0.4 ) in the placebo group ( P < .001 ) . The effect persisted for 2 years , with a mean increase of 1.7 percentage points ( 95 % CI , 0.7 to 2.7 ) versus a mean decrease of 1.2 percentage points ( 95 % CI , -1.8 to -0.5 ; P < .001 ) in the hormone and placebo groups , respectively . These effects were greater in women age 60 to 79 years ( P = .03 for interaction across age ) . CONCLUSION Use of CEE results in a modest but statistically significant increase in mammographic density that is sustained over at least a 2-year period . The clinical significance of the CEE effect on mammographic density remains to be determined .
42633
Intervention_Pharmacological
conjugated equine estrogens ( CEEs )
42634
Intervention_Pharmacological
daily CEE 0.625 mg
42635
Intervention_Control
placebo
42636
Outcome_Physical
mammographic density
42637
Outcome_Physical
mammographic percent density
42638
Outcome_Physical
mammographic density
42639
Outcome_Physical
mammographic density
42640
Participant_Condition
postmenopausal
42641
Participant_Sex
women
42642
Participant_Sex
women
42643
Participant_Sample-size
of 435 racially and ethnically diverse participants
42644
Participant_Sex
women
42645
Participant_Age
age 60 to 79 years