Having 3 or 4 Kids May Slow Down Biological Aging––Ummm What?!

by Virginia Duan
Originally Published: 
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A recent study just published in Nature found that the number of instances a person gives birth may impact a person’s physical aging process. Since I birthed four children, naturally, I was a bit concerned. After all, this has some serious repercussions — does this mean I’m going to get more wrinkles, or age or die earlier than other women? (I mean, other than risking death every time I navigate my stairs due to my children’s complete inability to keep the stairs clear of their toys and cast off clothes and slippers.)

No, but really, I’m very concerned about the wrinkles. I know Asian don’t raisin and I use South Korean beauty products, but I did birth a lot of tiny humans so I’m not sure what that means for me. Do they cancel each other out? Inquiring (and vain) minds want to know.

I confess, I read the Nature article and it hurt my head. In my defense, though I have a degree in microbiology and molecular genetics, that was 22 years ago and I wasn’t that good at my major anyway.

Thankfully, lead researcher Talia Shirazi and contributing researcher Waylon Hastings explained their main conclusion to Scary Mommy. “Women who had less than 3 kids or more than 4 kids showed signs of accelerated biological aging relative to women who had 3 or 4 kids…” they said, “but these signs of accelerated biological aging were only apparent… in postmenopausal women.”

In layperson’s terms, women who had 3 or 4 children were “younger” in biological age than other women — but these signs showed up only after menopause.

Their answer was a comfort because there really should be some benefits conferred to me for birthing 4 children — I mean, other than the sheer joy of raising them — but what does accelerated biological aging actually mean? Do your organs fail sooner? Do you die earlier? Is this a bad thing? (It sounds like a bad thing.)

What is biological aging?


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Biological age (also known as physiological or functional age) refers to the aging of your cells and tissues from gradually accumulated damage due to numerous genetic and non-genetic factors. It’s the age your body “acts” like versus the amount of time you have been alive — like an estimation of how well your body is operating.

Your actual biological age is determined by using mathematical models and accounts for various biological and physiological developmental factors such as:

  • Chronological age (the amount of time passed from your birth to a given date)
  • Genetics
  • Lifestyle
  • Nutrition
  • Diseases and other conditions

For the Penn State study, Shirazi and Hastings relied on 9 known clinical markers that change with age. These biomarkers are what clinicians use in a standard blood panel to determine how well specific organs are functioning or how likely you will get certain diseases (e.g.: diabetes). “These composites can predict things like an individual’s self-rated health, their cognitive function, limitations in their activities of daily living, morbidity, and mortality,” they explained, “with individuals with more accelerated biological age exhibiting worse outcomes.”

Stated another way, people who have a more advanced biological age would be more likely than those of a younger biological age to get chronic diseases (e.g.: heart disease, cancer) at an earlier chronological age.

What does this study mean and why does it matter?

Well, I’ll tell you what it doesn’t mean — it doesn’t mean that women who have 3 or 4 babies will live longer and everyone else is screwed. Rather, it gives us one more of many factors to consider in regards to aging such as genetics, lifestyle, and environment.

According to the study, the researchers are unable to make any sort of individual prediction of lifespan or health. Due to the limitations of the data and the study participants, while they found some correlation between number of children and physiological age, their data doesn’t allow them to draw any conclusions about whether the number of children causes an older or younger biological age after menopause (or vice versa). Those kinds of definitive statements are outside the scope of their data.

How to age well

Short of having 3 to 4 children, women — and people in general — can prevent accelerated biological aging by partaking in regular exercise, healthy eating, and practicing a good sleep regimen. Basically, do what doctors tell you to improve your general health.

And while we would like some easy predictor for aging — physiological or otherwise — ultimately it adds to our knowledge about aging and what causes biological age acceleration. “There are so many things that contribute to biological age acceleration, morbidity, and mortality,” said Shirazi and Hastings, “and the number of kids is likely just one small piece of the puzzle.”

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