Association of the Ratio of Second to Fourth Digit Length and Phthalate Exposure With Sexual Function in Japanese Men Seeking Fertility Treatment
Sexual dysfunction, which is increasingly recognized as a cause of male infertility, may be influenced by environmental factors such as phthalic acid diesters (phthalates) and prenatal androgen exposure. This study aimed to investigate the association between male sexual function and recent exposure...
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| Format: | Article |
| Language: | English |
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SAGE Publishing
2025-06-01
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| Series: | American Journal of Men's Health |
| Online Access: | https://doi.org/10.1177/15579883251352972 |
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| author | Kazumitsu Yamasaki Masahiro Uchida Yuki Mizuno Teruaki Iwamoto Shoko Konishi |
| author_facet | Kazumitsu Yamasaki Masahiro Uchida Yuki Mizuno Teruaki Iwamoto Shoko Konishi |
| author_sort | Kazumitsu Yamasaki |
| collection | DOAJ |
| description | Sexual dysfunction, which is increasingly recognized as a cause of male infertility, may be influenced by environmental factors such as phthalic acid diesters (phthalates) and prenatal androgen exposure. This study aimed to investigate the association between male sexual function and recent exposure to phthalates and prenatal testosterone. The cross-sectional study included 177 males seeking fertility treatment. The index-to-ring-finger length ratio (2D:4D) was calculated as a measure of prenatal androgen exposure. To evaluate recent phthalate exposure, urinary concentrations of seven phthalate metabolites were measured. Their associations with International Index of Erectile Function (IIEF) scores were analyzed using generalized linear models. One standard deviation increase of mono-methyl phthalate was negatively associated with IIEF domains A (erectile function; exponentiated coefficient, 0.95; exponentiated 95% confidence interval, CI, [0.91, 0.98]) and D (intercourse satisfaction; exponentiated coefficient, 0.91; exponentiated [0.85, 0.97]). While mono-butyl phthalate was positively associated with domain A, mono-ethyl phthalate, monobenzyl phthalate, and the molar sum of di (2-ethylhexyl) phthalate metabolites showed no significant association with IIEF domain scores. When the serum testosterone concentration was included as an exposure variable, the overall association between urinary phthalates and IIEF domain scores remained similar. The left- and right-hand 2D:4D ratios did not show significant associations with any IIEF domain scores. Recent phthalate exposure may affect male sexual function by decreasing testosterone levels and other potential mechanisms. |
| format | Article |
| id | doaj-art-65076d0fa3f84dc0a36d945bb3b5e619 |
| institution | Kabale University |
| issn | 1557-9891 |
| language | English |
| publishDate | 2025-06-01 |
| publisher | SAGE Publishing |
| record_format | Article |
| series | American Journal of Men's Health |
| spelling | doaj-art-65076d0fa3f84dc0a36d945bb3b5e6192025-08-20T03:28:21ZengSAGE PublishingAmerican Journal of Men's Health1557-98912025-06-011910.1177/15579883251352972Association of the Ratio of Second to Fourth Digit Length and Phthalate Exposure With Sexual Function in Japanese Men Seeking Fertility TreatmentKazumitsu Yamasaki0Masahiro Uchida1Yuki Mizuno2Teruaki Iwamoto3Shoko Konishi4Sanno Hospital, Minato-ku, Tokyo, JapanDepartment of Urology, Tsukuba Gakuen Hospital, Ibaraki, JapanDepartment of Human Ecology, School of International Health, Graduate School of Medicine, The University of Tokyo, JapanDepartment of Urology, St Marianna University, Miyamae-ku, Kawasaki, JapanDepartment of Human Ecology, School of International Health, Graduate School of Medicine, The University of Tokyo, JapanSexual dysfunction, which is increasingly recognized as a cause of male infertility, may be influenced by environmental factors such as phthalic acid diesters (phthalates) and prenatal androgen exposure. This study aimed to investigate the association between male sexual function and recent exposure to phthalates and prenatal testosterone. The cross-sectional study included 177 males seeking fertility treatment. The index-to-ring-finger length ratio (2D:4D) was calculated as a measure of prenatal androgen exposure. To evaluate recent phthalate exposure, urinary concentrations of seven phthalate metabolites were measured. Their associations with International Index of Erectile Function (IIEF) scores were analyzed using generalized linear models. One standard deviation increase of mono-methyl phthalate was negatively associated with IIEF domains A (erectile function; exponentiated coefficient, 0.95; exponentiated 95% confidence interval, CI, [0.91, 0.98]) and D (intercourse satisfaction; exponentiated coefficient, 0.91; exponentiated [0.85, 0.97]). While mono-butyl phthalate was positively associated with domain A, mono-ethyl phthalate, monobenzyl phthalate, and the molar sum of di (2-ethylhexyl) phthalate metabolites showed no significant association with IIEF domain scores. When the serum testosterone concentration was included as an exposure variable, the overall association between urinary phthalates and IIEF domain scores remained similar. The left- and right-hand 2D:4D ratios did not show significant associations with any IIEF domain scores. Recent phthalate exposure may affect male sexual function by decreasing testosterone levels and other potential mechanisms.https://doi.org/10.1177/15579883251352972 |
| spellingShingle | Kazumitsu Yamasaki Masahiro Uchida Yuki Mizuno Teruaki Iwamoto Shoko Konishi Association of the Ratio of Second to Fourth Digit Length and Phthalate Exposure With Sexual Function in Japanese Men Seeking Fertility Treatment American Journal of Men's Health |
| title | Association of the Ratio of Second to Fourth Digit Length and Phthalate Exposure With Sexual Function in Japanese Men Seeking Fertility Treatment |
| title_full | Association of the Ratio of Second to Fourth Digit Length and Phthalate Exposure With Sexual Function in Japanese Men Seeking Fertility Treatment |
| title_fullStr | Association of the Ratio of Second to Fourth Digit Length and Phthalate Exposure With Sexual Function in Japanese Men Seeking Fertility Treatment |
| title_full_unstemmed | Association of the Ratio of Second to Fourth Digit Length and Phthalate Exposure With Sexual Function in Japanese Men Seeking Fertility Treatment |
| title_short | Association of the Ratio of Second to Fourth Digit Length and Phthalate Exposure With Sexual Function in Japanese Men Seeking Fertility Treatment |
| title_sort | association of the ratio of second to fourth digit length and phthalate exposure with sexual function in japanese men seeking fertility treatment |
| url | https://doi.org/10.1177/15579883251352972 |
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