Association of urinary phytoestrogens with hormone-related cancers and cancer biomarkers: NHANES 1999-2010.

Phytoestrogens may have potential effects on hormone-related cancers (HRCs) and cancer biomarkers, but the findings have been inconsistent so far. Participants from the National Health and Nutrition Examination Survey 1999-2010 with information on the levels of urinary phytoestrogens, serum cancer biomarkers and cancer history were included. Sampling-weighted logistic regression models examined the association between urinary phytoestrogens concentrations (creatinine-standardized and log-transformed) and HRCs, followed by stratified analyses by race/ethnicity, age and menopausal status for different gender. Correlation analyses between phytoestrogens and cancer biomarkers were performed. Of the total 8,844 participants, there were 373 with HRCs. We observed total isoflavone and enterodiol excretion was positively associated with HRCs, especially in non-Hispanic white female subpopulations ( P trend <0.05). Similar association also existed in the total isoflavones and enterodiol levels with breast cancer. Whereas, the highest concentration of total isoflavones was significantly linked to a reduced prevalence of HRCs (OR = 0.40, 95% CI: 0.19-0.84) in white males and of prostate cancer (OR = 0.40, 95% CI: 0.18-0.86). Among 24 participants with HRCs, urinary equol concentration was positively correlated with CA15.3. Also, an inverse correlation of total PSA and positive correlation of the PSA ratio with urinary enterolactone were detected in 13 prostate cancer patients. But no significant correlation was found in all normal subjects. Our findings indicated that higher concentrations of total isoflavones and enterodiol were positively associated with HRCs. Urinary certain phytoestrogen excretion may affect serum cancer biomarker levels in cancer patients. But further prospective studies are needed to provide stronger evidence.