Research Paper Volume 10, Issue 9 pp 2383—2393

Reproductive history and blood cell telomere length

Jacob K. Kresovich1, , Christine G. Parks1, , Dale P. Sandler1, , Jack A. Taylor1,2, ,

  • 1 Epidemiology Branch, National Institute of Environmental Health Sciences, NIH, Research Triangle Park, NC 27709, USA
  • 2 Epigenetic and Stem Cell Biology Laboratory, National Institute of Environmental Health Sciences, NIH, Research Triangle Park, NC 27709, USA

Received: July 6, 2018       Accepted: September 10, 2018       Published: September 19, 2018
How to Cite

Copyright: © 2018 Kresovich et al. This is an open access article distributed under the terms of the Creative Commons Attribution License (CC BY 3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.


Telomeres are repetitive nucleotide sequences that protect against chromosomal shortening. They are replenished by telomerase, an enzyme that may be activated by estrogen. Women have longer telomeres than men; this difference might be due to estrogen exposure. We hypothesized that reproductive histories reflecting greater estrogen exposure will be associated with longer blood cell telomeres. Among women in the Sister Study (n= 1,048), we examined telomere length in relation to self-reported data on reproductive history. The difference between age at menarche and last menstrual period was used to approximate the reproductive period. Relative telomere length (rTL) was measured using qPCR. After adjustment, rTL decreased with longer reproductive period (β= -0.019, 95% CI: -0.04, -0.00, p= 0.03). Premenopausal women had shorter rTL than postmenopausal women (β= -0.051, 95% CI: -0.12, 0.01, p= 0.13). Longer breastfeeding duration was associated with longer rTL (β= 0.027, 95% CI: 0.01, 0.05, p=0.01); increasing parity was associated with shorter rTL (β = -0.016, 95% CI: -0.03, 0.00, p=0.07). Duration of exogenous hormone use was not associated with rTL. Reproductive histories reflecting greater endogenous estrogen exposure were associated with shorter rTL. Our findings suggest that longer telomeres in women are unlikely to be explained by greater estrogen exposure.


BMI: Body mass index; METs: Metabolic equivalent tasks; HSC: Hematopoietic stem cells; qPCR: Quantitative polymerase chain reaction; rTL: Relative telomere length; TERT: Telomerase reverse transcriptase.