| Project/Area Number |
11670350
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Hygiene
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| Research Institution | Keio University |
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Principal Investigator |
TAKEBAYASHI Toru Keio University School of Medicine Assistant Professor, 医学部, 専任講師 (30265780)
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| Co-Investigator(Kenkyū-buntansha) |
NISHIWAKI Yuji Keio University School of Medicine Instructor, 医学部, 助手 (40237764)
SUEOKA Koh Keio University School of Medicine Associate Professor, 医学部, 助教授 (90162833)
OMAE Kazuyuki Keio University School of Medicine Professor, 医学部, 教授 (60118924)
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| Project Period (FY) |
1999 – 2000
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| Project Status |
Completed (Fiscal Year 2000)
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| Budget Amount *help |
¥3,700,000 (Direct Cost: ¥3,700,000)
Fiscal Year 2000: ¥1,100,000 (Direct Cost: ¥1,100,000)
Fiscal Year 1999: ¥2,600,000 (Direct Cost: ¥2,600,000)
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| Keywords | endocrine disruptor / semen / epidemiology / reproduction |
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| Research Abstract |
1. Critical review of epidemiological evidence on changes in semen quality
We evaluated reports on changes in semen quality published on medical journals since 1992 to see whether semen quality has been deteriorated or not over time. As a result, some reported decline in semen quality, but others reported as unchanged. Geographical and seasonal variations as well as measurement error may largely contribute to changes in semen quality. Therefore, with critical review of recent epidemiological studies, we could not conclude that semen quality has been deteriorated over time.
2. Analysis of changes in semen quality of Japanese semen donor samples
We analyzed 10906 semen quality data from 325 Japanese semen donors who visited infertility clinic in Tokyo in 1990-1998. A regression coefficient for semen concentration (all data) was-1.16 x 106/ml/year, which might indicate that semen concentration has been declined over time. However, similar analysis with the first sample of each donor only, a regression coefficient for semen concentration was not statistically significant. Additional analysis with median value of first 6 months for each also failed to show significant results. Thus, we conclude that we could not observe significant decline in semen concentration of Japanese semen donors in 1990-98.
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