A new study finds women who use anti-inflammatory drugs have lower hormone levels than non users by as much as 15 percent.
Exactly why painkillers lower estrogen levels is not certain. But one theory is that painkillers inhibit the expression of an enzyme called aromatase that converts testosterone to a form of estrogen. If you block that, you're not making as much estrogen.
Scientists reporting in Cancer Epidemiology, Biomarkers and Prevention say the findings may explain the association between painkiller use and lower breast cancer risk. They say the data is strong linking lower estrogen levels to lower risk of breast cancer.