Sedentary lifestyles and obesity are known risk factors for breast cancer. Elevated estrogen levels correlate with obesity and, independently, with increased breast cancer risk. Lifestyle interventions that reduce obesity may mitigate this risk, potentially via estrogen pathways. In a 6-month lifestyle intervention, overweight/obese women with high breast cancer risk were randomized to control (n = 7) or intervention (n = 6) and analyzed for sex hormone levels. Serum and urine hormones were evaluated by ultra performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) and sex hormone binding globulin (SHBG) by enzyme-linked immunosorbent assay (ELISA). Serum estrone (E1) and estradiol (E2) were reduced by 12.1% and 50.8%, respectively, at 9 months in the intervention group, which differed from controls (p = .043 and .020). This contrasted with a 73.3% increase in urine E1 at 6 months in the intervention group (p = .035). These results suggest that a lifestyle intervention led to a favorable estrogen profile in relation to breast cancer risk.
Trial registration: ClinicalTrials.gov NCT01874184.
Keywords: breast neoplasms; estrogens; mindfulness; public health; weight loss.