A new study has identified an interesting new influence on the wear and tear on our cells.
It turns out your biological age could be affected by whether or not your grandparents attained a college degree, suggesting the benefits of socioeconomic status can be passed down not just to the next generation, but also the generation after that.
Generally speaking, spending longer in education is associated with higher incomes and better health for individuals. Now it seems that the knock-on effect can extend for generations, something we've previously related to diet.
"We know from animal studies that health is transmitted across several generations, from grandparents to grandchildren," says epidemiologist Agus Surachman from Drexel University in the US.
"But we now have robust human data that shows that not only do parents' socioeconomic factors play a role in their children's health, but that influence goes back an extra generation as well."
As our cells experience the stressful knock and grind of everyday life, they increasingly lock up sequences of DNA using chemical processes such as methylation. Not only can measures of epigenetic processes reflect a degree of biological age, they can hint at stresses that caused similar genetic modifications in generations past.
The study team used survey records, blood samples, and saliva swabs from 624 middle-aged women and 241 of their children, aged between 2 and 17 years. Details on the women's parents had been collected through an earlier study conducted in the late 1980s through the 1990s.
An analysis of the participants' DNA methylation suggested the rate of biological aging was slower in children whose grandparents had completed college.
The difference wasn't huge, but we are talking about kids and young people in the early part of their lives, and those differences could end up being more significant later in life, potentially even affecting mortality rates.
Certain factors were controlled for, including age and body mass index (BMI). The researchers also found that 14.5 percent of the variability in epigenetic aging was influenced by the mother's own educational attainment, as well as health factors like their cardiovascular health and inflammation.
"The link between a grandparent's socioeconomic status and a grandchild's epigenetic age is a remarkable finding, across generations," says Elissa Epel, from the University of California, San Francisco.
"This opens up a myriad of possible explanations and will need to be replicated. For now, we know that the mother's poorer metabolic health is a partial mediator of this relationship."
The kids involved in the study will continue to be tracked to see how their health progresses over time, but it's a reminder of the many different factors that play into our well-being – not all of which we're responsible for.
"There's a lot of blaming people for their poor health," says Surachman. "But the reality is that health is much more complex than that."
"Some factors are simply beyond our control, such as the genetics and the inherited epigenetics we are born with. I hope this helps us give more grace and compassion to ourselves and our communities."
The research has been published in Social Science and Medicine.