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Tattoo exposure and biomarkers of male fecundity : A cross-sectional study among young Danish males

Dornfeldt, Mette Møller ; Dan Hull, Sidsel ; Nielsen, Christel LU orcid ; Liljedahl, Emelie Rietz LU orcid ; Ramlau-Hansen, Cecilia Høst ; Gaml-Sørensen, Anne ; Toft, Gunnar ; Bonde, Jens Peter ; Hougaard, Karin Sørig and Tøttenborg, Sandra Søgaard LU (2025) In Reproductive Toxicology 137.
Abstract

Background: Tattoo inks are mixtures of organic and inorganic color pigments and having a tattoo may be adversely associated with biomarkers of male fecundity. Objective: To examine the association between tattoo exposure and biomarkers of male fecundity. Methods: Participants were young adult Danish males (aged 18–21 years) sampled from the Danish National Birth Cohort. Upon recruitment in 2017–2019, participants answered a comprehensive questionnaire including information on tattoo exposure and provided a semen and blood sample. We applied a negative binomial regression model to estimate percentage differences (95 % confidence intervals [CI]) in semen characteristics, testicular volume, and reproductive hormone levels between tattooed... (More)

Background: Tattoo inks are mixtures of organic and inorganic color pigments and having a tattoo may be adversely associated with biomarkers of male fecundity. Objective: To examine the association between tattoo exposure and biomarkers of male fecundity. Methods: Participants were young adult Danish males (aged 18–21 years) sampled from the Danish National Birth Cohort. Upon recruitment in 2017–2019, participants answered a comprehensive questionnaire including information on tattoo exposure and provided a semen and blood sample. We applied a negative binomial regression model to estimate percentage differences (95 % confidence intervals [CI]) in semen characteristics, testicular volume, and reproductive hormone levels between tattooed and non-tattooed participants. Results: Among the 1045 participants included in this study, 174 (17 %) had at least one tattoo and most tattooed participants (84 %) had tattoo(s) in only black color. About half (53 %) had one tattoo, 21 % had two tattoos, and 26 % had three or more tattoos. We observed no association between either number or color scheme of tattoo(s) relative to semen characteristics or reproductive hormone levels. Having a tattoo was associated with 6 % (95 % CI: 0, 12) larger testicular volume, but since testicular volume was measured by the participants themselves, this finding may be due to differential misclassification bias. Across all outcomes the crude and adjusted models were comparable. Conclusion: Overall, we found no support for adverse associations between tattoo exposure and biomarkers of male fecundity, but studies with more details on tattoo exposure and longer follow-up of participants are needed before firm conclusions can be drawn.

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organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
male fecundity, reproductive hormones, semen, Tattoo, testicles
in
Reproductive Toxicology
volume
137
article number
109009
publisher
Elsevier
external identifiers
  • pmid:40712897
  • scopus:105011948683
ISSN
0890-6238
DOI
10.1016/j.reprotox.2025.109009
language
English
LU publication?
yes
additional info
Publisher Copyright: © 2025 The Authors
id
06bffc01-f398-448c-a3db-dacc050e2fc3
date added to LUP
2025-08-11 08:59:15
date last changed
2025-08-12 03:12:33
@article{06bffc01-f398-448c-a3db-dacc050e2fc3,
  abstract     = {{<p>Background: Tattoo inks are mixtures of organic and inorganic color pigments and having a tattoo may be adversely associated with biomarkers of male fecundity. Objective: To examine the association between tattoo exposure and biomarkers of male fecundity. Methods: Participants were young adult Danish males (aged 18–21 years) sampled from the Danish National Birth Cohort. Upon recruitment in 2017–2019, participants answered a comprehensive questionnaire including information on tattoo exposure and provided a semen and blood sample. We applied a negative binomial regression model to estimate percentage differences (95 % confidence intervals [CI]) in semen characteristics, testicular volume, and reproductive hormone levels between tattooed and non-tattooed participants. Results: Among the 1045 participants included in this study, 174 (17 %) had at least one tattoo and most tattooed participants (84 %) had tattoo(s) in only black color. About half (53 %) had one tattoo, 21 % had two tattoos, and 26 % had three or more tattoos. We observed no association between either number or color scheme of tattoo(s) relative to semen characteristics or reproductive hormone levels. Having a tattoo was associated with 6 % (95 % CI: 0, 12) larger testicular volume, but since testicular volume was measured by the participants themselves, this finding may be due to differential misclassification bias. Across all outcomes the crude and adjusted models were comparable. Conclusion: Overall, we found no support for adverse associations between tattoo exposure and biomarkers of male fecundity, but studies with more details on tattoo exposure and longer follow-up of participants are needed before firm conclusions can be drawn.</p>}},
  author       = {{Dornfeldt, Mette Møller and Dan Hull, Sidsel and Nielsen, Christel and Liljedahl, Emelie Rietz and Ramlau-Hansen, Cecilia Høst and Gaml-Sørensen, Anne and Toft, Gunnar and Bonde, Jens Peter and Hougaard, Karin Sørig and Tøttenborg, Sandra Søgaard}},
  issn         = {{0890-6238}},
  keywords     = {{male fecundity; reproductive hormones; semen; Tattoo; testicles}},
  language     = {{eng}},
  publisher    = {{Elsevier}},
  series       = {{Reproductive Toxicology}},
  title        = {{Tattoo exposure and biomarkers of male fecundity : A cross-sectional study among young Danish males}},
  url          = {{http://dx.doi.org/10.1016/j.reprotox.2025.109009}},
  doi          = {{10.1016/j.reprotox.2025.109009}},
  volume       = {{137}},
  year         = {{2025}},
}