Trait anxiety and tamoxifen effects on bone mineral density and sex hormone- binding globulin

OBJECTIVE: Tamoxifen therapy preserves BMD of the lumbar spine and increases levels of SHBG. We assessed whether trait anxiety, a factor linked with a reactive endocrine system, is associated with differential changes in BMD and SHBG levels in response to tamoxifen therapy. METHODS: Postmenopausal women (N= 140) with axillary-node-negative breast cancer participated in a 2-year randomized, double-blind, placebo-controlled trial of tamoxifen (10 mg twice a day). Levels of BMD and SHBG were assessed at baseline and at 3, 6, 12, 18, and 24 months. RESULTS: Trait anxiety predicted tamoxifen-induced changes in lumbar spine BMD; high levels of trait anxiety were associated with significantly greater lumbar spine BMD at 3, 12, and 24 months (p values <.05) for women on tamoxifen therapy. High anxiety also was associated with lower levels of SHBG for women using tamoxifen at 3, 12, 18, and 24 months (p values <.05). CONCLUSIONS: Trait anxiety is associated with greater preservation of lumbar spine BMD in response to tamoxifen and with a suppression of tamoxifen-induced increases in SHBG. Trait anxiety and other affective traits may serve as indicators of underlying physiological processes that moderate the effects of estrogen receptor modulators (such as tamoxifen) in clinical trials. Such data may help to elucidate the physiological mechanisms responsible for some of the variation in individual responses to treatment.