Lifelong social connections may slow biological aging and reduce inflammation

A lifetime of rich social connections, from warm parental relationships in childhood to deep community engagement in adulthood, may physically slow the aging process at a cellular level. New research suggests that the cumulative effect of these social advantages is associated with a younger biological age and lower levels of chronic inflammation. The findings were published in the journal Brain, Behavior, & Immunity – Health.

The study was conducted by a team of researchers, led by Anthony Ong, a professor of psychology at Cornell University, who sought to understand how social experiences become embedded in our biology over the course of a life. It is well established that strong social ties are linked to better health and longer life. However, access to these resources is not equal, and advantages or disadvantages can accumulate over time, leading to growing health differences between people. The researchers proposed that these long-term patterns of social connection, which they call “cumulative social advantage,” might be reflected in the body’s core regulatory systems that govern aging.

To investigate this idea, the researchers analyzed data from 2,117 adults participating in the Midlife in the United States study, a large, long-term project tracking the health and well-being of a national sample of Americans. The participants had an average age of 55 years. The scientists first created a comprehensive measure of cumulative social advantage by combining 16 different self-reported indicators. These indicators captured a wide range of social resources across a person’s life.

“Cumulative social advantage is really about the depth and breadth of your social connections over a lifetime,” Ong said. “We looked at four key areas: the warmth and support you received from your parents growing up, how connected you feel to your community and neighborhood, your involvement in religious or faith-based communities, and the ongoing emotional support from friends and family.” This combined score was designed to reflect not just a person’s current social life, but a sustained history of social connectedness.

Next, the researchers examined biological data collected from the participants. They looked at three different physiological systems. The first was epigenetic aging, which was assessed using seven different “epigenetic clocks.” These are sophisticated algorithms that analyze patterns of chemical tags on DNA, known as DNA methylation, to estimate a person’s biological age.

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Unlike chronological age, which is simply the number of years a person has been alive, biological age reflects the health and condition of their cells and tissues. Two of these clocks, GrimAge and DunedinPACE, are specifically designed to predict mortality risk and the pace of physiological decline.

The second system was systemic inflammation. The team measured the levels of eight different biomarkers in the blood that indicate chronic, low-grade inflammation throughout the body. This type of persistent inflammation is a known driver of many age-related diseases. Key markers included Interleukin-6, a central pro-inflammatory protein, and C-reactive protein. The third system was neuroendocrine function, which relates to the body’s stress response.

The researchers analyzed overnight urine samples to measure levels of hormones like cortisol and catecholamines, including epinephrine and norepinephrine. The scientists then used statistical models to see if there was a relationship between a person’s cumulative social advantage score and their biological markers, after accounting for factors like age, sex, race, education, and income.

The results showed a consistent pattern linking social advantage to healthier biology. Individuals with higher cumulative social advantage scores tended to have slower epigenetic aging. This connection was apparent across all seven epigenetic clocks, but it was strongest for the GrimAge and DunedinPACE clocks. This finding suggests that people with a lifetime of richer social ties were biologically younger than their peers with fewer social resources.

The analysis also revealed a link between social advantage and the immune system. Higher scores for cumulative social advantage were associated with lower levels of systemic inflammation, with the most robust connection seen for the biomarker Interleukin-6.

“What’s striking is the cumulative effect, these social resources build on each other over time,” Ong said. “It’s not just about having friends today; it’s about how your social connections have grown and deepened throughout your life. That accumulation shapes your health trajectory in measurable ways.”

The study did not find a significant association between cumulative social advantage and the neuroendocrine markers from the overnight urine samples. The researchers suggest that this might be because these hormones fluctuate rapidly and an overnight sample may not capture the most meaningful aspects of the body’s stress response. The connections were most evident in biological systems that reflect long-term wear and tear, like epigenetics and chronic inflammation, rather than short-term stress hormone output.

“Think of social connections like a retirement account,” Ong said. “The earlier you start investing and the more consistently you contribute, the greater your returns. Our study shows those returns aren’t just emotional; they’re biological. People with richer, more sustained social connections literally age more slowly at the cellular level. Aging well means both staying healthy and staying connected, they’re inseparable.”

The authors note some limitations of their work. Because the study was a cross-sectional analysis, meaning it looked at data from a single point in time, it cannot prove that social advantage causes slower aging. It is possible that people who are healthier to begin with are better able to build and maintain strong social networks. Future research that follows individuals over many years will be needed to establish a clearer cause-and-effect relationship. Additionally, other unmeasured factors, such as genetics or early-life adversity, could be influencing both social resources and biological health.

Future studies could also explore which specific aspects of social advantage are most impactful on health. The current measure was heavily influenced by indicators of community engagement, so further work could disentangle the unique effects of family support versus broader social integration. Researchers may also need to use more intensive methods for measuring stress hormones, such as collecting saliva samples multiple times a day, to get a more dynamic picture of how social experiences affect the body’s stress response systems in real time.

The study, “Cumulative social advantage is associated with slower epigenetic aging and lower systemic inflammation,” was authored by Anthony D. Ong, Frank D. Mann, and Laura D. Kubzansky.