Many postmenopausal women who have had treatment for breast cancer take a category of drug called Aromatase Inhibitors after their primary treatment for the cancer is completed. The purpose of this drug is to block any estrogen formation that may further stimulate the recurrence of breast cancer.

This category of drugs has many side effects for the women taking it. One of the most common side effects is musculoskeletal symptoms including joint pain.

 In this study, the authors measured vitamin D levels at the beginning of the study as the women were started on the Aromatase Inhibitor drug . The drug used in this study was letrozole (Trade name Femara).  They gave one group of women 50,000 IU of vitamin D per week. The other group did not take any more than the usual amount of vitamin D that comes with calcium pills.( Usually this is 400 IU) . After 16 weeks of the aromatase inhibitor they found that more women with vitamin D levels greater than 66 ng/ml reported no disability from joint pain than did women whose levels were lower than 66 ng/ml.

If you have a woman in your life who is taking aromatase inhibitors after chemotherapy for breast cancer be sure to remind her to have her doctor check her vitamin D level and to optimize it.

There are two important things to note in this article. Number one, the authors made no mention of the other benefit that the vitamin D alone would provide in protecting the woman from future breast cancer. The second important thing in this article is that they brought the women’s levels all the way up to 66 ng/ml. This is much higher than studies normally do, and the authors note that the women experienced no side effects from vitamin D (which we would not expect anyway). This level of 66 ng/ml is much more in keeping with the recommendations that I have  made in my book for optimal levels for all people.

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