Taking an aromatase inhibitor for early breast cancer? Check your vitamin D...

A paper just published in the journal Maturitas (the journal of the European Menopause and Andropause Society) is a reminder the importance of vitamin D in breast cancer treatment. As the authors observe:

"Aromatase inhibitors (AI) treatment leads to an increased risk of bone loss and fractures."

The authors examined a group of women with early breast cancer (EBC) and baseline Vitamin D deficiency (<30 ng/ml) who were treated with aromatase inhibitors. They followed serum levels of Vitamin D, bone mineral density (BMD), calcium intake, and the increase of serum 25(OH)D from 3 months of Vitamin D supplementation. What did their data show?

"At baseline [the beginning of AI therapy], 88.1% had 25(OH)D levels <30 ng/ml, 21.2% had severe deficiency (<10 ng/ml), and 25% of the participants had osteoporosis...We found a significant association between 25(OH)D levels and BMD...Plasma 25(OH)D levels improved significantly at 3 months follow-up in those treated with high dose Vitamin D supplements."

This is only one aspect of the crucial role of Vitamin D in breast cancer prevention and treatment. The authors' conclusion should be borne in mind by all those caring for or dealing with breast cancer:

"Our study suggests a high prevalence of commonly unrecognized Vitamin D deficiency in women with EBC treated with AI, a known osteopenic agent. Our results support the need for a routine assessment of 25(OH)D levels and, when necessary, supplementation in these patients."

For a discussion of aromatase inhibitors versus tamoxifen see this recent post.