Is Soy Intake Related to Bone Fractures for Breast Cancer Survivors?
Posted: Friday, August 9, 2019
New findings presented in JNCI Cancer Spectrum present reportedly the first evidence of an inverse relationship between soy food intake and osteoporotic fractures for pre- and perimenopausal women who have been previously diagnosed with breast cancer. Xiao-Ou Shu, MD, PhD, MPH, of the Vanderbilt-Ingram Cancer Center, Nashville, and colleagues also noted that being overweight or obese may be linked to an increased risk for osteoporotic fractures among premenopausal breast cancer survivors.
“Our findings, if confirmed, can help guide development of comprehensive fracture risk reduction strategies (eg, through patient screening, diagnosis, treatment, and self-care approaches) in this vulnerable population,” the authors wrote.
This prospective study analyzed data from 4,139 cases of stage 0 to III breast cancer and included 1,987 pre- and perimenopausal women and 2,152 postmenopausal women. The investigators assessed fractures at 18 months and every 3, 5, and 10 years after patients were diagnosed with breast cancer. Exercise and soy isoflavone intake were evaluated 6 and 18 months after diagnosis.
Among the pre- and perimenopausal women, 10-year osteoporotic fractures occurred at a rate of 2.9%, compared with 4.4% for postmenopausal patients. A higher intake of soy isoflavone resulted in a reduced risk of fractures for pre- and perimenopausal women (hazard ratio = 0.22), but not for postmenopausal women.
Among patients who were overweight, pre- and perimenopausal women were found to be at a higher risk for fractures (hazard ratio = 1.81), whereas investigators found a statistically nonsignificant reduced risk for postmenopausal women. Additionally, exercise and tamoxifen use were both inversely associated with fractures in postmenopausal patients.
“Observation of increased risk of bone fracture among breast cancer survivors in our study is consistent with previous reports, such as those from the Women’s Health Initiative and the Austrian Breast and Colorectal Cancer Study Group-18 trial, and was the catalyst for investigating its risk factors in this vulnerable population,” the authors observed.
Disclosure: The study authors reported no conflicts of interest.