Effects of a dietary modification intervention on menstrual pain and urinary BPA levels: a single group clinical trial

BACKGROUND: Exposure to endocrine-disrupting chemicals (EDCs) occurs mainly through dietary intake. Due to current lifestyle trends, young people tend to consume fast food, to use disposable products, and to utilize convenient household items, all of which are major sources of EDCs. This study aimed to investigate the effects of a dietary modification intervention on menstrual pain and urinary bisphenol A (BPA) levels throughout three menstrual cycles in female college students who experienced severe menstrual pain. We also analyzed participants’ adherence to the intervention and examined whether their level of adherence was associated with differences in the effects of the intervention. METHODS: A single-group pretest and repeated posttest experimental design was employed. Thirty female college students with a score of 5 or higher on a menstrual pain scale were recruited through convenience sampling. During three menstrual cycles, menstrual pain was scored on a 10-point scale after each cycle, and urinary BPA levels were measured from the first morning urine collected after each cycle. The intervention involved three components: small-group education, follow-up monitoring, and peer support via social network communication. Statistical analyses were conducted using Friedman one-way repeated-measure analysis of variance by ranks, non-parametric two-way analysis of variance, and the Wilcoxon signed-rank test as a post-hoc test. RESULTS: The dietary modification intervention had significant effects on menstrual pain at all three time points of menstrual cycles (χ(2) = 119.64, p = 0.000) and on urinary BPA levels until the 2(nd) menstrual cycle (χ(2) = 205.42, p = 0.000). Slightly fewer than half (43.3%) of the participants were highly adherent. Menstrual pain differed according to adherence level (F = 4.67, p = 0.032) and decreased over time through the third cycle post-intervention (F = 18.30, p = 0.000). Urinary BPA levels also decreased significantly (F = 7.94, p = 0.000), but did not differ according to adherence level. CONCLUSIONS: The dietary modification intervention was effective and sustainable for reducing menstrual pain and urinary BPA levels. Detailed information about EDCs and dietary experiences seemed to encourage the young women to become more concerned about EDCs and to perform self-protective actions. Further experimental research is suggested to examine the relationships of EDCs with various health indicators in women. Trial registration: KCT0005472 at 2020-9-24 retrospectively registered.