Persistently difficult people in a person’s life may be doing more than souring the day. They could be quietly accelerating how fast the body ages, according to a study published in the Proceedings of the National Academy of Sciences.
The researchers use the term “hasslers” for people who regularly create conflict, problems or unnecessary stress. The study found that each additional hassler in a person’s social network was associated with roughly 1.5 per cent faster biological ageing, and about nine months of extra biological age compared with peers of the same chronological age.
Biological age is not the same as the number of years since birth. It is an estimate of how worn the body is at the cellular level, and the team measured it using DNA methylation clocks drawn from saliva samples. In plain terms, two people born in the same year can carry different biological ages depending on how their cells have weathered over time.
The effect was not rare in the sample. The researchers reported that about 28.8 per cent of participants had at least one hassler in their network, and roughly one in 10 had two or more. That points to persistently negative ties being a fairly ordinary feature of everyday social life rather than an unusual one.
Where the hassler sat mattered a great deal. The study found the strongest and most consistent association among family members, ahead of difficult friends or colleagues. Notably, difficult spouses showed no significant link to faster ageing in the analysis, while the presence of any kin hassler was associated with about 1.1 additional years of biological ageing, and any non-kin hassler with about 0.83 years.
The researchers offered a structural explanation for the family pattern. Kin relationships tend to be embedded in a person’s life in ways that are hard to escape, unlike a colleague one can avoid or a friendship one can quietly drop. That difficulty of exit, they suggested, is part of what makes such ties heavier to carry over time.
The proposed mechanism is chronic stress. Scientists believe strained relationships act as steady, low grade stressors that keep the body under psychological strain, which over time may wear down its resilience, raise inflammation and increase the risk of illness. The study also linked a higher count of hasslers to poorer mental health and to a greater likelihood of multiple chronic conditions.
An important caution runs through the findings. The authors were careful to say the study shows an association, not proof of cause. As the lead author, Byungkyu Lee, a sociology professor at New York University, put it, “We do not know whether hasslers actually cause people to age. What we observe here is a kind of association between having hasslers and the rate of aging.”
The distinction matters for how the results should be read. It is possible that difficult relationships speed up ageing, but it is also possible that people who are already in poorer health, or under other forms of strain, are more likely to accumulate difficult ties in the first place. The design of the study cannot separate those directions with certainty.
The size of the effect also deserves proportion. A 1.5 per cent faster pace sounds small year to year, and it is. The researchers noted that over a decade it accumulates to only a modest amount of extra biological ageing per additional hassler. Some independent coverage of the work has framed the effect as equivalent to a fraction of the ageing gap seen between daily smokers and non-smokers, which places it as measurable but far from dominant among the many factors that shape how people age.
There are limits worth stating clearly. The sample was drawn from a state-representative population in Indiana in the United States, so how directly the numbers translate to other societies, including Nigeria, is not established. Family structures, living arrangements and social obligations differ across cultures, and the study does not claim a universal figure that applies everywhere.
Still, the direction of the finding sits within a broader and better established body of evidence. Researchers have long documented that the quality of social relationships, not merely their quantity, is tied to long term health. This study adds a specific, measurable marker to that picture by attaching a biological ageing estimate to the burden of difficult ties.
For readers, the practical takeaway is measured rather than alarming. The work does not suggest cutting off relatives or treating every disagreement as a health threat. What it points to is that the steady stress of consistently difficult relationships may register in the body over time, and that managing or reducing exposure to chronic conflict, where possible, sits alongside the more familiar advice on diet, sleep and exercise. What it cannot yet say is whether changing those relationships would change the ageing outcome.