HealthDay News — Higher soy consumption is linked to fewer osteoporotic fractures in younger breast cancer survivors, according to a study published online May 21 in JNCI Cancer Spectrum.
Neil Zheng, from Yale University in New Haven, Connecticut, and colleagues investigated incidence of osteoporotic bone fracture and its associations with soy food consumption, exercise, and body mass index among 4139 stage 0 to III breast cancer patients, 1,987 pre-/perimenopausal patients, and 2152 postmenopausal patients participating in the Shanghai Breast Cancer Survival Study.
The researchers found that the 10-year incidence for osteoporotic fractures was 2.9% for pre-/perimenopausal and 4.4% for postmenopausal patients. There was an association between high soy isoflavone intake and reduced risk among pre-/perimenopausal patients (hazard ratio [HR], 0.22 [95% confidence interval [CI], 0.09 to 0.53] for soy isoflavone mg/d ≥56.06 vs <31.31; Ptrend < 0.001), but not among postmenopausal patients (Pinteraction < 0.01). Compared with normal weight, overweight was a risk factor for pre-/perimenopausal patients (HR, 1.81; 95% CI, 1.04 to 3.14), but not for postmenopausal patients (HR, 0.67; 95% CI, 0.43 to 1.03; Pinteraction = 0.01). There was an inverse association between exercise and osteoporotic fractures in postmenopausal patients (HR, 0.56 [95% CI, 0.33 to 0.97] for metabolic equivalent hours ≥12.6 vs <4.5) with a dose-response pattern (Ptrend = 0.035).
“Our findings, especially the novel association of soy food intake with osteoporotic fractures in breast cancer survivors, if confirmed, can help guide future strategies for fracture risk reduction in this vulnerable population,” the authors write.