Having Annoying Relatives Could Speed Up Your Biological Clock

Why Parents And Siblings, Not Your Spouse, May Be Your Biggest Aging Risk

Most people have one. A parent who can’t get through a phone call without a cutting remark. A sibling whose entire personality seems engineered to cause problems. A grown child who drains every gathering of its energy. New research suggests these relatives aren’t just making life more frustrating for other family members. They may be causing them to age faster, too.

Researchers found that family members, more than coworkers, neighbors, or even difficult spouses, showed the strongest links to accelerated biological aging when they regularly hassled, burdened, or created problems for someone in their network. Having any family member in that category was associated with a biological age roughly a year older than peers of the same calendar age, and with cells aging measurably faster. Spouses, despite years of research spotlighting marital conflict as a health hazard, showed no statistically meaningful effect on the aging clocks used in this study.

The finding runs counter to the instinct to blame a bad marriage first. According to the study, the family ties hardest to exit and loaded with the most obligation, parents, children, siblings, may be doing the most quiet biological damage.

How Family ‘Hasslers’ Drive Faster Biological Aging

Scientists drew on a large health study conducted across Indiana called the Person-to-Person Health Interview Study. Their final sample included 2,345 adults ranging in age from 18 to 103.

To measure biological aging, the team analyzed DNA extracted from participants’ saliva samples, using two well-validated molecular tools called GrimAge2 and DunedinPACE. Rather than measuring how old someone looks or feels, these tools read chemical changes in DNA that track how fast the body’s cells are deteriorating. GrimAge2 captures cumulative biological age relative to calendar age, essentially how much older your biology is than your birthday suggests. DunedinPACE works more like a speedometer, capturing the current rate of cellular aging. Both have been linked in prior research to mortality risk and chronic disease.

To identify who qualified as a “hassler,” participants named the people in their lives and rated whether each person “often” hassled them, caused problems, or made their lives more difficult. Occasional friction didn’t count. Hasslers were people who did this regularly.

About 29% of the full sample of 2,685 participants reported having at least one hassler in their close network. Roughly 10% had two or more. That puts persistently difficult relationships in the same category as other common health exposures that rarely get discussed in the same breath as diet or exercise.

The biological costs tracked closely with relationship type. Family hasslers, specifically parents, children, and siblings, showed the most consistent links to both measures of accelerated aging. Non-family hasslers, such as coworkers or acquaintances, also showed a significant association with one of the two aging clocks, the one measuring cumulative biological age. Spouse hasslers showed no statistically significant association with either measure.

The paper, published in the Proceedings of the National Academy of Sciences, offers a structural explanation for why family stands out. Kin ties carry obligation; they are harder to renegotiate or exit than friendships or even work relationships. When a family member is also a source of repeated stress, there are fewer options to disengage and fewer compensatory mechanisms to offset the harm. As the study puts it, the structural embeddedness that usually signals social protection can “become a pathway for chronic stress” when anchored in a difficult relationship, turning what would normally be a source of support into a source of biological risk.

Each Additional Hassler Adds About Nine Months of Biological Age

Zoom out from the family finding and the numbers are still worth sitting with. Across the entire sample, each additional hassler in a person’s close network was associated with roughly nine months of extra biological age and a pace of cellular aging about 1.5% faster per year. That accumulates: over a decade, that faster pace translates to roughly 18 extra months of biological aging for someone carrying one additional hassler compared to someone without one.

To benchmark those numbers, the authors compared them to smoking, one of the most studied behavioral drivers of accelerated aging. The hassler association corresponded to roughly 13 to 17% of the biological aging gap typically observed between non-smokers and smokers. That is not a trivial fraction.

Hassler exposure also turned out to be unequally distributed, tracking closely with existing vulnerabilities. Women were more likely to report having hasslers than men. People with more adverse childhood experiences showed higher hassler counts in adulthood. Daily smokers and those in poorer health also reported more hasslers. In short, the people already dealing with the most also tended to have more difficult people in their lives, a compounding effect the authors describe as a form of “relational inequality.”

Difficult Relationships Linked To Depression, Inflammation, And Chronic Illness

Biological aging was far from the only health domain affected. Each additional hassler was associated with higher depression and anxiety scores, poorer self-rated mental and physical health, higher BMI, worse waist-to-hip ratios, and higher rates of multiple chronic conditions occurring at the same time. Inflammation markers from the same DNA samples followed suit. Chronic social stress appears to put the body’s internal alarm systems on a slow burn, repeatedly triggering the release of stress hormones like cortisol and adrenaline. Over time, that persistent activation feeds inflammation at the molecular level, wearing down the body across multiple systems at once.

One obvious question is whether the arrow points the other way. Maybe people in declining health attract more difficult relationships rather than cause them. To check, the team used follow-up survey data collected years after the initial interviews and found that having more hasslers at baseline still predicted worse health later, even after accounting for how healthy participants were at the start. Controlling for smoking history, childhood adversity, occupation, and pre-existing illness didn’t change the picture, and neither did accounting for the elevated household tensions of the COVID-19 pandemic period.

Most people endure difficult relatives because it feels like the only option. What this research adds is that the body doesn’t simply absorb that strain and move on. It registers it, and over time, the registration shows up at the cellular level.

Disclaimer: This article is based on an observational study and does not establish that difficult relationships directly cause accelerated aging. Associations between hasslers and biological aging measures remained after extensive statistical controls, but the research cannot rule out all alternative explanations. Readers experiencing chronic stress related to difficult relationships are encouraged to consult a qualified mental health professional.

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Paper Notes

Limitations

This study is cross-sectional at its core, meaning researchers measured hasslers and biological aging at the same point in time. That design cannot definitively prove that hasslers cause accelerated aging, only that the two are associated. While the team used follow-up health data and several statistical methods to reduce the likelihood that reverse causation or pre-existing illness explains the findings, those steps cannot fully substitute for a long-term experimental design. Hassler exposure was measured through self-report, which means individual personality traits or negative dispositions could influence how many people a respondent labels as a hassler. The authors partially addressed this by controlling for respondents’ general attitudes toward others, but dispositional confounding cannot be fully ruled out. The study also relied on saliva rather than blood for DNA methylation, which can yield somewhat different baseline readings for the aging clocks used; researchers note that this does not affect the rank-ordering of associations. The sample was drawn from Indiana and may not be representative of other U.S. states or populations elsewhere. Finally, the study used only one survey item to identify hassling behavior, which means it could not distinguish between different forms of relational negativity such as hostility, criticism, coercion, or emotional manipulation.

Funding and Disclosures

Research was supported by the National Institute on Aging of the National Institutes of Health under award number R01AG076032, with principal investigator Brea Perry. Additional funding came from the Indiana University Office of the Vice President for Research through the Precision Health Grand Challenge, the Indiana Biobank, and the Indiana Clinical and Translational Sciences Institute (Grant Number UL1TR002529). The authors declared no competing interests.

Publication Details

Authors: Byungkyu Lee (New York University), Gabriele Ciciurkaite (Utah State University), Siyun Peng (University of South Florida), Colter Mitchell (University of Michigan–Ann Arbor), and Brea L. Perry (Indiana University–Bloomington).

Journal: Proceedings of the National Academy of Sciences (PNAS), 2026, Vol. 123, No. 8, Article e2515331123. | Paper title: “Negative social ties as emerging risk factors for accelerated aging, inflammation, and multimorbidity.” | DOI: 10.1073/pnas.2515331123 | Published: February 18, 2026. Received June 27, 2025; accepted January 22, 2026. Data and replication code are available via Harvard Dataverse (DOI: 10.7910/DVN/XEUYCZ) and GitHub (https://github.com/letitbk/p2p-hassler-replication).