IntroductionPremenstrual syndrome (PMS) comprises a range of mood, behavioural and physical symptoms, and impairs many women’s quality of life. Isoflavones are expected to stabilise the natural fluctuation of the oestrogen cycle through their selective oestrogen receptor modulator-like activities that alleviate PMS symptoms. Equol, a metabolite of a soy isoflavone converted from daidzein by specific gut bacteria, has a greater bioavailability compared with other soy isoflavones. We aim to examine the effect of natural S-equol supplements on premenstrual symptoms.Methods and analysisThis study will enrol 124 women (aged 20–45 years) who have PMS symptoms and are non-equol producers in a double-blind, parallel, randomised, placebo-controlled trial, in which they will receive natural S-equol supplement (equol 10 mg a day) or placebo, orally, twice daily, for three menstrual cycles. The primary outcome measure (Daily Record of Severity of Problems total score) will be assessed during intervention cycles. To compare the primary outcomes between the S-equol group and the placebo group, the mean differences in the Daily Record of Severity of Problems total score between the two groups will be determined. The p values will be determined using Student’s t-test, where the significance level is 5% (two-sided).Ethics and disseminationThe institutional review board at Kindai University approved the study. The findings of this trial will be submitted to an international peer-reviewed journal. Abstracts will be submitted to national and international conferences.Trial registration numberUMIN000031815.
ObjectivesTo investigate the relationship between the occurrence of stress fracture and premenstrual syndrome (PMS)/premenstrual dysphoric disorder (PMDD) in Japanese adolescent athletes.DesignCross-sectional study.SettingOsaka, Japan.ParticipantsA school-based survey on menstruation and school life was conducted using a sample of 1818 Japanese female students who belonged to two public high schools in Japan. Among them, we recruited 394 athletes who had regular menstrual cycles (25–38 days) and completed a questionnaire about their premenstrual symptoms and their competitive career.Main outcome measurePremenstrual symptoms and the occurrence of stress fracture.ResultsThe prevalences of moderate-to-severe PMS and PMDD were 8.9% and 1.3%, respectively, which were the same as in collegiate athletes in a previous study. Premenstrual symptoms disturbed ‘Work efficiency or productivity, home responsibilities’, ‘Relationships with coworkers or family’ and ‘Athletic performance in training or competition’ more severely than menstrual pain (p=0.031, p=0.004 and p<0.001, respectively). 66 athletes (16.8%) reported having experienced a stress fracture. The severity of ‘Overeating or food cravings’, ‘Physical symptoms’ and ‘Performance in training or competition’ in athletes with previous stress fractures were much higher than in those without a history of stress fractures (p=0.015, p=0.008 and p=0.006, respectively). In terms of premenstrual symptoms, ‘Physical symptoms’ was associated with an increased risk of stress fractures in athletes (OR 1.66, 95% CI 1.06 to 2.62).ConclusionsThe results from this study indicated that premenstrual symptoms may affect athletic performance and has the risk of stress fractures in adolescent athletes.
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