Date of Conferral
Doctor of Public Health (DrPH)
Mary Lou Gutierrez
Prostate cancer (CaP) remains the most commonly diagnosed cancer and second leading cause of cancer mortality among men in several ethnic groups in the United States. Lower CaP incidence among Asian men has been attributed to increased intake of soy derived phytoestrogens (SDPs); however, its association has not been extensively explored in U.S. men. The purpose of this study was to determine the effect size of serum prostate specific antigen (sPSA) and serum estradiol (sE2) following dietary SDP intervention. The study was based on an original conceptual model that aims to avert early prostate tissue damage through identification of critical prevention endpoints. Research questions examined the correlation between dietary SDPs and sPSA and sE2 levels. This quantitative meta-analysis study used data abstracted from 8 randomized controlled trials yielding 530 participants ages 50-85. Outcome specific meta-analysis using the random effect model adjusted for heterogeneity and determined cumulative effect size that favored intervention. Odds ratios established a positive correlation between intake of dietary SDP and detection of serum SDP (sSDP) among treated groups. Positive correlations between both dietary and sSDP with sE2 levels, and inverse correlations between both dietary and sSDP with sPSA levels, were indicated among treated compared to placebo groups. Hedges' g, correlation, and standardized mean difference statistics confirmed analyses. Implications for positive social change include developing professional dietary standards to use SDPs for CaP chemoprevention among U.S. and other men, as well as a medical option for treatment of CaP. Further research exploring mechanisms of SDP action on hormones may be beneficial to men at risk for CaP and individuals at risk for other cancers linked to changes in hormonal levels.
Michelin, Ruel Slyfield, "The Effect of Phytoestrogen Chemoprevention of Prostate Cancer" (2011). Walden Dissertations and Doctoral Studies. 1064.