Urinary isoflavone and lignan phytoestrogen levels and risk of uterine fibroid in Jamaican women

Abstract

BackgroundIsoflavones and lignans are phytoestrogens, and therefore, are able to bind to and activate estrogen receptors. The resultant estrogenic or antiestrogenic effect is dependent on the concentration of these phytoestrogens relative to endogenous estrogens and the site of their action, among others. Thus, isoflavones and lignans act as selective estrogen receptor modulators; having a beneficial effect in some tissues while simultaneously causing deleterious changes in others. ObjectiveThis case-control study investigates the relationship between urinary concentrations of genistein, daidzein, equol, and enterolactone, and the presence of uterine leiomyomas (fibroids) in Jamaican women. DesignPhytoestrogen concentration in spot urine samples from 157 uterine fibroid cases and 171 fibroid-free controls diagnosed by ultrasonography, were assessed by Time-resolved Fluoroimmnoassay. Statistical evaluations were performed using SPSS 12.0. ResultsThe median concentration of urinary enterolactone was significantly different between uterine fibroid cases and controls (p=0.029). However, this was not observed to affect risk of uterine fibroid, as trends across quartiles of urine enterolactone did not differ significantly between cases and controls. Median urinary genistein (p=0.510), daidzein (p=0.838), equol (p=0.621), total isoflavones (0.510) and total phytoestrogens (p=0.084) were similar for both groups. Binary logistic regression analysis of quartiles of urine genistein, daidzein, equol, enterolactone, total isoflavones, and total phytoestrogens showed no association with uterine fibroid. ConclusionsUterine fibroid cases had a higher median urine concentration of enterolactone compared with controls. However, this was not observed to affect ones risk of fibroid. Neither was urine genistein, daidzein, equol total isoflavones, and total phytoestrogens observed to be associated with risk of uterine fibroid.