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Discover 15,299 clinical trials near Boston, Massachusetts. Find research studies in your area.
Showing 11661-11680 of 15,299 trials
NCT02524561
Combined estrogen and progestin therapy has been shown to increase mammographic density and incidence of breast cancer in randomized trials. The investigators propose to examine the effects of now commonly used low-dose combined hormone therapy (HT) regimens on breast density, rates of abnormal mammogram, and circulating estrogens in the ongoing, already-funded Kronos Early Estrogen Prevention Study (KEEPS). KEEPS is a randomized clinical trial with a primary goal of examining the effects of low-dose transdermal versus oral estrogen combined with cyclic micronized progesterone on progression of subclinical atherosclerosis in recently menopausal women. Prior studies of low-dose HT have been of short duration and small size. By determining the effects of low-dose hormone therapy on the breast, the proposed ancillary study will add important information about the estimated balance of risks and benefits associated with low-dose HT and will help guide future research trials.
NCT00950885
Melatonin supplements have been reported to be an effective treatment for circadian rhythm sleep disorders, including shift work dyssomnia, jet-lag, delayed sleep phase syndrome, and sleep disruption suffered by many blind individuals. However, the mechanism(s) by which melatonin affects the timing of sleep are not well-understood. The purpose of this study is to determine if melatonin improves sleep and performance on a schedule simulating eastward travel. This study will provide information regarding the mechanism of action of melatonin that will be critical for the use of melatonin as a treatment for circadian rhythm sleep disorders.