Does having more children slow down the aging process?
It has been suggested that having more offspring would lead to accelerated aging. One theory proposed for faster aging is that having a child results in the energy needed for reproduction being unavailable for cell and tissue maintenance. Results from studies on non-human animals support the latter hypothesis (Criscuolo et al., 2006; Kirkwood et al., 2002). However, aging is a very complex physiological process that is not well understood. The complexity of aging is exemplified by the relatively large variation in the rate of the aging process among individuals (Ricklefs et al., 2010).
In a recent paper by Cindy et al., 2019, they found that women who had more surviving children showed longer telomeres. This is interesting as telomere length is considered a marker of cellular aging with longer telomere length associated with a longer life span. The telomeres occur at the ends of chromosomes and are stretches of DNA that guard our genetic data, preventing chromosome ends form unravelling and attaching to each other. Each time a cell divides, these telomeres get shorter. Eventually, these telomeres get so short that the cell is unable to divide resulting in the cell dying or becoming inactive (senescent). Hence, a shorter telomere is associated with aging.
Let’s take a closer look at the study:
Seventy-five women from two nearby rural communities in Guatemala were investigated to determine the relationship between telomere length and the number of surviving children born to a woman.
Great approach: Using salivary specimens and buccal swabs the telomere lengths of the 75 women were measured 13 years apart.
Results: After considering the telomere length at the start of the 13-year period, women who had more children showed longer telomere lengths than those how had less children (p = 0.045).
In rural communities in Guatemala, having more children may result in better social support for mothers, lowering reproductive energy requirements (“ultimate cause”).
At a “proximate” level, it is possible that the steroid estradiol, which is known to significantly increase during pregnancy, protects telomere lengths from the oxidative stress and increased telomerase activity.
The number of women investigated is relatively small, and these women are from an indigenous community (Kaqchikel Mayan women). The results had a p-value of 0.045, which is close to being not statistically significant.
The women investigated ranged in age from 29 to 53. This is a relatively large age range considering that pregnancy-associated stress is suggested to be worst as women age.
The average number of surviving offspring in these women was 5.6 +/- 2.1. This is a relatively large variation in the number of surviving offspring which complicates the interpretation of the results. A woman with three surviving offspring versus a woman with seven surviving offspring may have differences in aging. The average number of surviving offspring is also large suggesting that the results presented would likely represent only a small percentage of the childbearing female population.
My Conclusion: We don’t know if having one or more children affects longevity. A great deal of research is needed for us to better understand aging and to determine if having more children slows down or speeds up the aging process. For now, have your kids, cherish them, and enjoy spending time with them. Having amazing, fun times with your kids may slow down your aging, but that’s a separate discussion.
Cindy K. Barha, Courtney W. Hanna, Katrina G. Salvante, Samantha L. Wilson, Wendy P. Robinson, Rachel M. Altman, Pablo A. Nepomnaschy. Number of Children and Telomere Length in Women: A Prospective, Longitudinal Evaluation. PLOS ONE, 2016; 11 (1): e0146424 DOI: 10.1371/journal.pone.0146424
Criscuolo F, Bertile F, Durant JM, Raclot T, Gabrielsen GW, Massemin S, et al. Body mass and clutch size may modulate prolactin and corticosterone levels in eiders. Physiological and biochemical zoology: PBZ. 2006;79(3):514–21. Epub 2006/05/13. pmid:16691517. DOI: 10.1086/501065
Kirkwood TB. Evolution of ageing. Mechanisms of ageing and development. 2002;123(7):737–45. Epub 2002/03/01. pmid:11869731. https://doi.org/10.1016/S0047-6374(01)00419-5
Ricklefs RE. Insights from comparative analyses of aging in birds and mammals. Aging cell. 2010;9(2):273–84. DOI: 10.1111/j.1474-9726.2009.00542.x