BTR Plc

Vitamin D2 in chronic dosing will produce less of an elevation of serum 25(OH)D than will the same dose of vitamin D3.

The overall goal of this project is to determine if high dose vitamin D3 given to premenopausal women at high risk for development of breast cancer, who initially have insufficient levels of 25-hydroxy vitamin D (<30 ng/ml), will raise 25(OH)D levels above 50 ng/ml. If so, will certain risk biomarkers for development of breast cancer be reliably and favorably modulated?

The primary purpose is to determine if high dose vitamin D3 reduces the incidence of musculoskeletal symptoms associated with the aromatase inhibitor letrozole in women with early stage breast cancer and low serum vitamin D levels.