The drug has been shown to reduce the incidence of breast cancer in healthy women at high risk of developing that disease. Similar to postmenopausal hormone therapy, tamoxifen was predicted to reduce cardiovascular risk on the basis of its cholesterol-lowering properties. CRP is a marker for low-grade inflammation. Fibrinogen is a blood coagulation factor and is also a marker of inflammation. High levels of these inflammatory markers have been associated with increased risk for cardiovascular disease in several studies, says Mary Cushman, M.D., M.Sc., lead author of the paper and assistant professor of medicine at the University of Vermont in Burlington.
Tamoxifen has mixed effects depending on the organ it's acting on.
Heart disease is the number one killer of American women. Previous breast cancer trials have reported 15 percent to 60 percent reductions in cardiac death in women treated with tamoxifen, and researchers linked this effect to the drug's lipid-lowering properties. Indeed, women on tamoxifen had a 9 percent reduction in total cholesterol levels in this study. However, Cushman reports that the effects on inflammatory markers were larger than on cholesterol. The study participants were a group of 111 healthy women who were participating in a breast cancer prevention trial called the National Surgical Adjuvant Breast and Bowel Program P-1 trial.