Prevalence and associated factors of delayed ejaculation: insights from a nationwide internet-based, cross-sectional survey on male sexual dysfunction in Japan.

Background: Among causes of male sexual dysfunction, the prevalence of delayed ejaculation (DE) is lower than that of premature ejaculation or erectile dysfunction (ED), and its epidemiology remains poorly characterized, particularly in Asian populations. Aim: To estimate DE prevalence and identify associated factors of DE in a nationwide sample of Japanese men. Methods: A cross-sectional, internet-based survey conducted by the Clinical Research Promotion Committee of the Japanese Society for Sexual Medicine between May 29 and June 24, 2023, targeted Japanese men aged 20-79 years through a general population panel. Among 6228 valid responses, 5331 men who reported sexual activity were included in the analysis. DE-related distress was used to define the condition. Data on demographics, medical comorbidities, lifestyle factors, and sexual function were collected. Participants were also asked whether they desired treatment for DE and whether they had consulted a physician regarding this condition. Associated factors were identified through multivariate logistic regression analysis. Outcomes: Prevalence of DE, associated demographic and clinical factors, treatment-seeking desire, and actual help-seeking behavior among sexually active Japanese men. Results: The prevalence of DE was 5.16%. Of the affected individuals, 58.18% desired treatment, but only 11.88% actually sought it. Multivariate analysis revealed that psychotropic drug use (odds ratio [OR] = 2.41), pelvic trauma (OR = 2.39), low partnership satisfaction (OR = 2.27), ED (OR = 2.04), neurological diseases (OR = 2.02), obesity (OR = 1.51), high frequency of masturbation (OR = 1.24), and high frequency of sexual intercourse (OR = 1.17) were significantly associated with DE (all Clinical Implications: These findings highlight that DE is associated with multiple psychological, sexual, and physical health factors and that treatment-seeking behavior remains low despite substantial distress. Strengths and Limitations: This large, nationwide epidemiological study on DE in Japan is the first with a robust sample size and multivariate analysis. However, the reliance on self-reported data and internet-based sampling may introduce reporting bias and limit generalizability. Conclusion: DE affects approximately 5% of sexually active Japanese men and shares many risk factors with ED. Although more than half of those with DE desire treatment, only a minority seek care. Greater clinical awareness and patient education are warranted.