Relation between premenstrual syndrome and equol-production status.

AimConsumption of isoflavones, which are predominantly derived from soybeans, reduces the risk of estrogen-related diseases, such as menopausal symptoms, breast cancer, osteoporosis, and cardiovascular disease. Equol is more bioavailable than other soy isoflavones, and equol producers are believed to benefit to a greater extent. This study was conducted to evaluate the relation between premenstrual syndrome (PMS) and equol-production status in Japanese reproductive-age women. MethodsThis was a cross-sectional, observational study. The study included 144 Japanese women aged 20-45 years. PMS patients (n=46) were recruited at three obstetrics and gynecology clinics. Control group women (n=98) who were not receiving therapy for PMS were recruited from the local area by advertisement. The participants' equol-production status was determined using urine samples collected after a soy challenge test. ResultsThe prevalence of equol producers was 41.8% in the control group and 23.9% in the patient group (P=0.042). Using univariate analysis, significant risk factors for equol non-producers were being a PMS patient and being younger. In multivariate analysis with a step-wise model, being a PMS patient (odds ratio, 2.342; 95% confidence interval, 1.021-5.698) was shown to be a significant risk factor for being an equol non-producer. ConclusionThis study showed a relation between PMS and equol-production status in Japanese women.