Strong and sustained supportive relationships over a lifetime can lower inflammation and slow down biological ageing, according to a new study.

Such relationships and engagement in community life may “reset” the body’s internal clocks to lower the person’s biological age, says the research published in the journal Brain, Behavior & Immunity – Health.

Researchers analysed data from more than 2,100 people who participated in a study called the Midlife in the United States.

They noted that people with greater “cumulative social advantage” showed slower rates of biological ageing and reduced levels of chronic inflammation. “Cumulative social advantage is really about the depth and breadth of your social connections over a lifetime,” study co-author Anthony Ong said.

The study focuses in particular on the body’s epigenetic clocks, which are molecular markers that estimate how quickly one is ageing. Two such clocks are DunedinPACE and GrimAge.

These markers on the DNA are among the best predictors of disease risk and lifespan, the study explains.

The participants with consistent social networks showed notably younger biological profiles on both these body clocks.

“We looked at four key areas,” Dr Ong said, “the warmth and support you received from your parents growing up, how connected you feel to your community and the neighbourhood, your involvement in religious or faith-based communities, and the ongoing emotional support from friends and family.”

The scientists theorised that social advantage could be reflected in the body’s core systems linked to ageing, such as its epigenetic, inflammatory, and neuroendocrine pathways. They found that a higher social advantage was linked to lower levels of an inflammation-causing molecule implicated in heart disease, neurodegeneration, and diabetes.

“It’s not just about having friends today, it’s about how your social connections have grown and deepened throughout your life,” Dr Ong said. “That accumulation shapes your health trajectory in measurable ways.”

The findings indicate that the depth and consistency of social connection, built over decades and different spheres of life, matter profoundly.

The study adds weight to the view that social life isn’t just about happiness or stress relief but a core determinant of health.

“Think of social connections like a retirement account. The earlier you start investing and the more consistently you contribute, the greater your returns,” Dr Ong said.

“Our study shows those returns are not just emotional, they’re biological. People with richer, more sustained social connections literally age more slowly at the cellular level. Ageing well means both staying healthy and staying connected – they are inseparable.”