Display options
Share it on

Hum Reprod. 2021 Jul 19;36(8):2309-2320. doi: 10.1093/humrep/deab077.

Impaired fecundity as a marker of health and survival: a Danish twin cohort study.

Human reproduction (Oxford, England)

L J Ahrenfeldt, S Möller, M J Wensink, M L Eisenberg, K Christensen, T K Jensen, R Lindahl-Jacobsen

Affiliations

  1. Unit of Epidemiology, Biostatistics and Biodemography, Department of Public Health, University of Southern Denmark, Odense, Denmark.
  2. The Danish Twin Registry, Department of Public Health, University of Southern Denmark, Odense, Denmark.
  3. OPEN-Open Patient data Explorative Network, Odense University Hospital, Odense, Denmark.
  4. Department of Clinical Research, University of Southern Denmark, Odense, Denmark.
  5. Interdisciplinary Centre on Population Dynamics (CPop), University of Southern Denmark, Odense, Denmark.
  6. Male Reproductive Medicine and Surgery, Department of Urology and Obstetrics & Gynecology, Stanford University School of Medicine, Stanford, CA, USA.
  7. Department of Clinical Biochemistry and Pharmacology, Odense University Hospital, Odense, Denmark.
  8. Department of Clinical Genetics, Odense University Hospital, Odense, Denmark.
  9. Department of Clinical Pharmacology, Farmacy and Environmental Medicine, University of Southern Denmark, Odense, Denmark.

PMID: 34009293 PMCID: PMC8496092 DOI: 10.1093/humrep/deab077

Abstract

STUDY QUESTION: Is fecundity, measured as self-reported time to first pregnancy (TTP), a marker for subsequent health and survival?

SUMMARY ANSWER: Long TTP was a marker for increased mortality among women and higher hospitalization rates for both women and men.

WHAT IS KNOWN ALREADY: Poor semen quality has been linked to increased mortality and morbidity from a wide range of diseases. Associations among fecundity, health and survival among women are still uncertain and studies on actual measures of fecundity and health outcomes are rare.

STUDY DESIGN, SIZE, DURATION: We performed a prospective cohort study of 7825 women and 6279 men, aged 18 and above with measures on first TTP, who participated in one of the Danish nation-wide twin surveys in 1994 (twins born 1953-1976) and 1998 (twins born 1931-1952). They were followed-up for mortality and hospital admissions from the interview until 2018.

PARTICIPANTS/MATERIALS, SETTING, METHODS: Twins were identified in the Danish Twin Registry and linked to Danish registers. TTP was restricted to the first pregnancy as a categorical outcome with cut-off points at 2, 10 and 18 months. We analysed the association between TTP and survival using a Cox proportional hazards model estimating hazards ratios (HRs) with 95% confidence intervals (CIs). Fine-Gray survival models were used to estimate sub-hazard ratios for specific causes of death allowing for competing risks. Using negative binomial regression, we estimated incidence rate ratios (IRRs) with 95% CIs for all-cause and cause-specific hospitalizations. All analyses were stratified by sex and adjusted for age at interview, birth cohorts, age at first attempt to become pregnant, smoking, years in school and BMI.

MAIN RESULTS AND THE ROLE OF CHANCE: In the total study population, 49.9% of women and 52.7% of men reported a TTP of less than 2 months, 30.8% of women and 29.6% of men reported a TTP of 2-9 months, 6.6% of women and 5.7% of men reported a TTP of 10-17 months, and 13.3% of women and 12.0% of men reported a TTP of 18 months or more. Among 1305 deaths, we found a higher mortality for women (HR = 1.46; 95% CI 1.15, 1.87) with a TTP of ≥18 months relative to those with a TTP of <2 months, while the highest mortality was indicated for men with a TTP of 10-17 months (HR = 1.31; 95% CI 0.98, 1.74). Among 53 799 hospitalizations, we found an increased hospitalization rate among women (HR = 1.21; 95% CI 1.0-1.41) and men (HR = 1.16; 95% CI 1.00-1.35) with a TTP of ≥18 months, and for men with a TTP of 2-9 months (HR = 1.14; 95% CI 1.01-1.30). A dose-response relationship was found for women regarding both mortality (P = 0.022) and hospitalizations (P = 0.018). Impaired fecundity was associated with a wide range of diseases and some causes of death, indicating a multi-factorial causal influence on fecundity, especially among women.

LIMITATIONS, REASONS FOR CAUTION: A major limitation was that fecundity depends on both partners, which was not considered in this study. Moreover, we could not obtain information on a number of potential confounders.

WIDER IMPLICATIONS OF THE FINDINGS: Fecundity seems positively correlated with overall health and may be a universal marker of future health and survival. These results add knowledge to the limited findings showing that reduced fecundity in women and poor semen quality in men may reflect worse health and a shorter life, particularly among women.

STUDY FUNDING/COMPETING INTEREST(S): This study was funded by NIH grant HD096468 (M.L.E., T.K.J. and R.L.J.). The authors declare that they have no competing interests.

TRIAL REGISTRATION NUMBER: N/A.

© The Author(s) 2021. Published by Oxford University Press on behalf of European Society of Human Reproduction and Embryology.

Keywords: hospitalization; infertility; mortality; subfertility; time to pregnancy

References

  1. PLoS Med. 2020 Sep 22;17(9):e1003332 - PubMed
  2. Epidemiology. 1998 Mar;9(2):189-92 - PubMed
  3. Clin Exp Reprod Med. 2020 Sep;47(3):213-220 - PubMed
  4. J Paediatr Child Health. 2020 Sep;56(9):1351-1357 - PubMed
  5. Hum Reprod. 2014 Jul;29(7):1567-74 - PubMed
  6. Trends Cardiovasc Med. 2020 Oct;30(7):399-404 - PubMed
  7. Front Neuroendocrinol. 2011 Apr;32(2):170-82 - PubMed
  8. Scand J Public Health. 2011 Jul;39(7 Suppl):75-8 - PubMed
  9. Fertil Steril. 2013 Sep;100(3):681-5 - PubMed
  10. Twin Res Hum Genet. 2019 Dec;22(6):499-507 - PubMed
  11. Am J Epidemiol. 2009 Sep 1;170(5):559-65 - PubMed
  12. Fertil Steril. 2015 Jan;103(1):66-71 - PubMed
  13. Acta Obstet Gynecol Scand. 1995 Sep;74(8):614-8 - PubMed
  14. Aging Male. 2012 Sep;15(3):134-9 - PubMed
  15. Reproduction. 2019 Sep;158(3):R79-R90 - PubMed
  16. Am J Obstet Gynecol. 2019 May;220(5):473.e1-473.e14 - PubMed
  17. Cell Metab. 2016 Jun 14;23(6):1022-1033 - PubMed
  18. Endocrinology. 2019 Nov 1;160(11):2719-2736 - PubMed
  19. BMC Med. 2010 Jun 30;8:41 - PubMed
  20. BMJ. 2000 Sep 30;321(7264):789-92 - PubMed
  21. Reprod Biol Endocrinol. 2020 Mar 17;18(1):23 - PubMed
  22. J Epidemiol Community Health. 1989 Sep;43(3):268-74 - PubMed
  23. Hum Reprod. 2015 Feb;30(2):493-4 - PubMed
  24. J Am Coll Nutr. 2004 Dec;23(6 Suppl):588S-595S - PubMed
  25. Hum Reprod. 2017 Mar 1;32(3):499-504 - PubMed
  26. Fertil Steril. 2018 Oct;110(5):810-814 - PubMed
  27. Arch Gynecol Obstet. 2021 Mar;303(3):631-643 - PubMed
  28. J Cardiovasc Thorac Res. 2018;10(2):56-69 - PubMed
  29. Hum Reprod. 2019 Nov 1;34(11):2266-2273 - PubMed
  30. Epidemiology. 2000 May;11(3):340-3 - PubMed
  31. Scand J Public Health. 2011 Jul;39(7 Suppl):12-6 - PubMed
  32. Reprod Biol Endocrinol. 2020 Mar 12;18(1):21 - PubMed
  33. Environ Res. 2019 Apr;171:119-133 - PubMed
  34. J Assist Reprod Genet. 2017 Feb;34(2):167-177 - PubMed
  35. Am J Epidemiol. 2017 Oct 15;186(8):910-917 - PubMed
  36. Investig Clin Urol. 2020 Jul;61(4):355-371 - PubMed
  37. Fertil Steril. 2015 Aug;104(2):391-7 - PubMed
  38. Andrology. 2018 May;6(3):428-435 - PubMed
  39. Clin Epidemiol. 2015 Nov 17;7:449-90 - PubMed
  40. JAMA. 2012 Feb 1;307(5):491-7 - PubMed
  41. Hum Reprod. 2007 Jan;22(1):188-96 - PubMed
  42. Reprod Biol Endocrinol. 2013 Jul 16;11:66 - PubMed
  43. Fertil Steril. 2016 Mar;105(3):629-636 - PubMed
  44. Int J Epidemiol. 1992 Dec;21(6):1151-6 - PubMed
  45. Fertil Steril. 2004 Oct;82(4):863-70 - PubMed
  46. J Clin Endocrinol Metab. 2011 Oct;96(10):3007-19 - PubMed
  47. Am J Epidemiol. 1996 Mar 15;143(6):578-87 - PubMed
  48. Scand J Public Health. 2011 Jul;39(7 Suppl):22-5 - PubMed
  49. Eur Heart J. 2010 Jun;31(12):1494-501 - PubMed
  50. Lancet Diabetes Endocrinol. 2020 Feb;8(2):134-149 - PubMed
  51. Fertil Steril. 2020 Sep;114(3):618-627 - PubMed
  52. Physiol Rev. 2016 Jan;96(1):55-97 - PubMed
  53. Scand J Public Health. 2011 Jul;39(7 Suppl):26-9 - PubMed
  54. Fertil Steril. 2020 Nov;114(5):984-996 - PubMed
  55. BMJ. 1992 Sep 12;305(6854):609-13 - PubMed
  56. Hum Reprod. 2019 May 1;34(5):894-902 - PubMed
  57. Int J Epidemiol. 1995 Jun;24(3):589-96 - PubMed
  58. Diabetologia. 2015 Apr;58(4):707-15 - PubMed
  59. Fertil Res Pract. 2017 Apr 11;3:7 - PubMed
  60. Hum Reprod. 2014 Jul;29(7):1471-89 - PubMed
  61. J Epidemiol Community Health. 1995 Jun;49(3):314-9 - PubMed
  62. Lancet. 2009 Mar 28;373(9669):1083-96 - PubMed
  63. Nicotine Tob Res. 2016 Nov;18(11):2154-2161 - PubMed
  64. Arch Womens Ment Health. 2021 Feb;24(1):11-27 - PubMed

MeSH terms

Publication Types

Grant support