Very Low Uptake in Workplace Semen Analysis Research: Formative Web-Based Cross-Sectional Follow-Up Survey Distinguishing Employees With Self-Reported Unawareness From Aware Nonparticipants

BACKGROUND: Very low uptake in workplace semen-analysis research is difficult to interpret, particularly in employer-adjacent settings, where nonparticipation may reflect limited recruitment reach, limited understanding of the occupational rationale, low perceived relevance, or procedure-related concerns. OBJECTIVE: This post hoc formative study described self-reported awareness of a parent workplace semen-analysis study as an indicator of effective recruitment reach, reported reasons for nonparticipation under the implemented survey condition, and design issues for exposure-defined workplace reproductive-health research. METHODS: In April-May 2025, we conducted an anonymous web-based cross-sectional follow-up survey among male employees in Japan who had been eligible for, but had not completed, a parent workplace semen-analysis study. The parent study invited approximately 2000 male employees from 3 companies between November 2024 and January 2025; 6 completed the protocol. The follow-up survey invited approximately 900 male employees from 1 company. Part 1 assessed awareness, reasons for nonparticipation, interest in male reproductive-health information, and general openness to future related research. Optional Part 2 assessed age, knowledge, concerns, expected reactions, and willingness under simplified conditions. Responses were summarized descriptively using Wilson 95% CIs; no hypothesis testing was performed. RESULTS: We analyzed 108 submitted questionnaires; 83 respondents completed Part 2. Overall, 74/108 respondents (68.5%, 95% CI 59.3%-76.5%) reported no awareness of the parent study. Among unaware respondents, 68/74 (91.9%, 95% CI 83.4%-96.2%) selected "did not know the study existed." Among aware nonparticipants, the most frequent reasons were perceived irrelevance and resistance to collecting semen (each 9/34, 26.5%, 95% CI 14.6%-43.1%), embarrassment or reluctance (8/34, 23.5%, 95% CI 12.4%-40.0%), and hassle (7/34, 20.6%, 95% CI 10.3%-36.8%). In Part 2, anxiety about unfavorable results was reported by 52/83 respondents (62.7%, 95% CI 51.9%-72.3%), concerns about collection location and/or privacy protection by 48/83 (57.8%, 95% CI 47.1%-67.9%), and self-reported resistance by 42/83 (50.6%, 95% CI 40.1%-61.1%). Under simplified conditions, 36/83 respondents (43.4%, 95% CI 33.2%-54.1%) indicated willingness to undergo semen analysis. CONCLUSIONS: Very low uptake was not interpretable as a single phenomenon. This post hoc formative process evaluation identified limited awareness, suggesting limited effective recruitment reach, as self-reported under the implemented procedures, while aware nonparticipants reported low perceived relevance and semen-collection-related concerns. The findings do not identify primary causal determinants of nonparticipation; rather, they identify recruitment-cascade components that future studies should measure prospectively: objective exposure to recruitment materials, information access, understanding of the occupational rationale, post-information declination, privacy concerns, logistical burden, and specimen-return completion. Because the survey did not provide occupational reproductive-hazard education or assess comprehension, it should not be interpreted as evidence of informed acceptability after such education.