Evaluation of temporal changes in the sexual function among Japanese women using the female sexual function index: An Internet survey

OBJECTIVES: Female sexual dysfunction is an underestimated problem that negatively affects women’s quality of life. Although the overall prevalence of sexual dysfunction in women is high, only a few studies have focused on this problem. In Japan, an index of female sexual function has not been clearly defined. Hence, this study aimed to investigate the sexual function of normal Japanese women and the temporal changes they experienced using the Female Sexual Function Index administered online in 2012 and 2019. METHODS: The subjects were Japanese women aged 20–79 years registered in an Internet research company. We collected data of 1034 and 2031 women in 2012 and 2019, respectively, based on Japan’s population distribution according to age. Subsequently, we analyzed the collected data using a Japanese version of the Female Sexual Function Index. We investigated the temporal changes in the Female Sexual Function Index total score, the ratio of women who did not engage in sexual activities and women having “no sexual activity” with their partners, and the total Female Sexual Function Index scores according to age. RESULTS: The average Female Sexual Function Index total score decreased from 14.6 in 2012 to 12.5 in 2019 (p < 0.001). No significant difference was observed in the average Female Sexual Function Index score of the group with sexual activity between 2012 (22.2) and 2019 (22.4). The ratio of women not engaging in sexual activities increased from 42.2% in 2012 to 54.0% in 2019. The ratio of women having “no sexual activity” with their partners increased by 10%. CONCLUSION: Comparison of data between 2012 and 2019 indicated that Japanese women have become less sexually active. The average Female Sexual Function Index total score of 22 may be useful as a reference value for diagnosing female sexual dysfunction in Japan.