Three Decades of Change in Frequency of Sexual Intercourse and Sexual Function Among Japanese Men: A Comparative National Survey.
Level 4 - case-series / case-control
Repeated cross-sectional comparison using historical survey cohorts
PubMed 41531270 · doi:10.1111/iju.70344
What was done
Authors compared self-reported sexual health data across two surveys conducted 32 years apart: the 1991 Sapporo Survey (limited to married men; n = 8,893 for intercourse frequency, 7,517 for morning erections, and 3,886 for penile rigidity) and the 2023 Japanese Society for Sexual Medicine Nationwide Survey (n = 3,795 men aged 20–79 years). Definitions were standardized across studies, and comparative analyses were restricted to married men from the 2023 dataset to align with the 1991 sample. Outcomes analyzed were sexual intercourse frequency, sufficiency of penile rigidity for penetration, and frequency of morning erections.
What was found
The abstract does not report specific percentages, odds ratios, or exact p-values, but describes the following directional findings: - Intercourse frequency: Reporting sexual intercourse less than once per month was significantly higher in 2023 than in 1991 across all age groups, except among men in their 20s. - Penile rigidity: The proportion of men with insufficient penile rigidity for penetration was significantly higher in 2023 than in 1991 across all age groups, except those aged 75 years and older. - Morning erections: Complete absence of morning erections was significantly more common in 2023 across all age groups.
Why it matters
These findings indicate multi-decade population-level declines in both sexual activity and markers of erectile capacity among married Japanese men, notably affecting younger and middle-aged groups.
Limits
No quantitative values (proportions, risk estimates, or confidence intervals) are provided in the abstract. The 1991 sample was geographically restricted to Sapporo with substantial item non-response, whereas the 2023 survey was national. Outcomes rely entirely on subjective recall and self-report, and potential shifts in survey methodology, medical comorbidities, or medication usage between 1991 and 2023 are not detailed.