ID.1
Item
prescribed tam as adjuvant therapy for early stage (0, i, ii, iiia) breast cancer or as chemoprevention in women at high risk for breast cancer
boolean
ID.2
Item
new or planned prescription of tam therapy; ineligible for randomization until on tam for > 3 months with the expectation to continue use for > 18 months
boolean
ID.3
Item
mammogram with breast imaging reporting and data system (birads) score of >= 2; (equivalent to the following and similar breast density descriptive terms found in mammogram reports: 2 = scattered fibroglandular elements/densities; 3 = heterogeneously dense tissue; 4 = extremely dense tissue)
boolean
ID.4
Item
no use of soy-based dietary supplements or willingness to discontinue use, complete a 4-week wash-out period, prior to randomization, and refrain from use during trial period
boolean
ID.5
Item
if pre-menopausal, non-pregnant (confirmed with urinary pregnancy test); practicing birth control or s/p oophorectomy
boolean
ID.6
Item
able to complete study run-in activities, including taking study-provided placebo pill twice daily (am & pm) and recording pill intake and any symptoms experienced on a study calendar, with a compliance rate of at least 80%
boolean
ID.7
Item
normal blood chemistry test that includes sodium and specific kidney and liver function tests (creatinine, alanine amino transferase-alt, aspartate amino transferase-ast) within 30 days of study enrollment; (informed consent form signed)
boolean
ID.8
Item
no history of hyponatremia
boolean