Changes in the prevalence of menstrual-related symptoms and menstrual cycle abnormalities among Japanese Summer and Winter Olympic athletes over the past seven Olympic Games

Background: Menstrual-related symptoms and menstrual cycle abnormalities linked to low energy availability can have detrimental long-term health consequences. However, longitudinal data regarding the prevalence trends of these conditions in elite athlete populations remain limited. Objectives: To investigate changes in the prevalence of menstrual-related symptoms and menstrual cycle abnormalities among Japanese female Summer and Winter Olympic athletes over 12 years. Design: A repeated cross-sectional study using retrospective data was applied. Methods: Data from Japanese female athletes competing in four Summer Olympic Games (Beijing 2008, London 2012, Rio 2016, Tokyo 2020 (held in 2021)) and three Winter Olympic Games (Vancouver 2010, Sochi 2014, PyeongChang 2018) were analyzed. Gynecological questionnaires assessed menstrual cycle status, symptoms, and medication usage. Trends were analyzed using logistic regression (main analysis) and generalized estimating equations (GEE) to account for repeated participation. Results: Among 954 athletes, 786 non-hormonal contraceptive users were analyzed. The prevalence of irregular menstrual cycles significantly increased over 12 years (odds ratio (OR) per cycle: 1.24, 95% confidence interval (CI): 1.13–1.37; p < 0.001). While the trend for dysmenorrhea was borderline in the main analysis ( p = 0.055), the GEE analysis revealed a significant increase (OR per cycle: 1.11, 95% CI: 1.03–1.19; p = 0.005). No significant trends were observed for primary amenorrhea, delayed menarche, premenstrual syndrome, or heavy menstrual bleeding. The gynecological consultation rate (all 954 athletes) increased significantly from 12.4% to 65.3% (OR: 1.42, 95% CI: 1.33–1.52; p < 0.001). Conclusion: Irregular menstrual cycles significantly increased among elite Japanese female athletes over 12 years. Furthermore, accounting for repeated participation revealed a significantly increasing trend in dysmenorrhea. These findings highlight the need for continued comprehensive gynecological support and education to optimize the health and performance of female athletes.