Evidence map›Paper›PMID 40944570›Full record

ArticleInternational journal of cancer2026

Long-term impact of stressful life events on breast cancer risk: A 36-year genetically informed prospective study in the Finnish Twin Cohort.

Elissar Azzi, Hannes Bode, Teemu Palviainen, Mikaela Hukkanen, Miina Ollikainen, Jaakko Kaprio

Abstract readTwin Study
In one paragraph

Article in International journal of cancer, 2026. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 2 papers.

0numbers the graph read from it
0cells of the map it votes in
2citing papers in PubMed
–field-weighted citation impact
1 · What the graph read from it

What it found

Each row is one number read from the abstract, on the scale the paper reported it, with its interval. Left of the dashed line favours the treatment, right favours the comparator. Under each row is the sentence it came from. New to these charts? A ten-minute tutorial.

The abstract states no effect estimate the extractor could read, or names no intervention and outcome on the map, so this paper lights no cell and moves no belief. It is still indexed, cited and linked below.

2 · The registry

The trial behind it

Trials whose registry record cites this paper, or whose number appears in the abstract. A trial that started after this paper was published is citing it as background, not reporting it.

Neither the registry nor the abstract names a trial number. If this is a trial report, that itself is worth knowing.

3 · Its place in the literature

Who cites it

2 citing papers in PubMed.

  1. Article
  2. Article
4 · The record

Corrections and comments

PubMed lists nothing against this paper. Absence here is not a guarantee, only a check that was made.

5 · Who and what money

Authors and funding

6 authors.

Elissar AzziInstitute for Molecular Medicine Finland (FIMM), University of Helsinki, Helsinki, Finland.ORCID https://orcid.org/0009-0004-1091-7346
Hannes BodeInstitute for Molecular Medicine Finland (FIMM), University of Helsinki, Helsinki, Finland.
Teemu PalviainenInstitute for Molecular Medicine Finland (FIMM), University of Helsinki, Helsinki, Finland.
Mikaela HukkanenInstitute for Molecular Medicine Finland (FIMM), University of Helsinki, Helsinki, Finland.
Miina OllikainenInstitute for Molecular Medicine Finland (FIMM), University of Helsinki, Helsinki, Finland.
Jaakko KaprioInstitute for Molecular Medicine Finland (FIMM), University of Helsinki, Helsinki, Finland.

Funding

Academy of Finland 251316Academy of Finland 297908Academy of Finland 307339Academy of Finland 328685Broad Institute 6910369-5500001940Emil Aaltosen Säätiö 23005Medicinska Understödsföreningen Liv och HälsaMinerva FoundationSigrid Juséliuksen SäätiöSyöpäsäätiö 67-6796Yrjö Jahnssonin Säätiö 20237645
6 · The paper itself

Abstract

Breast cancer (BC) is influenced by both genetic and environmental factors, but the long-term impact of stressful life events (SLEs) remains unclear. We examine the association between SLEs and BC risk using cohort and twin-pair analyses with 36 years of follow-up in the Finnish Twin Cohort, including 10,342 women and 719 BC cases. SLEs were assessed in 1981 by a questionnaire, while cancer incidence and mortality data were obtained from Finnish registries. Polygenic risk score for breast cancer (PRS-BC) and DNA methylation (DNAm) profiling were used to explore the underlying genetic and epigenetic factors. Cox proportional hazards models showed a significant association between SLEs and breast cancer risk (HR = 1.05 per event, 95% CI: 1.02-1.08). As few as 2-3 SLEs were associated with a 24% increased risk (HR = 1.24, 95% CI: 1.00-1.54), emphasizing the impact of even a modest number of events. Within-pair analyses in monozygotic twins suggested non-genetic factors mediate this association. Stratification by birth cohort revealed a stronger effect in women born before 1950 (HR = 1.07, 95% CI: 1.01-1.12). While PRS-BC was not significantly associated with breast cancer risk, DNAm analysis identified 42 BC-associated CpG sites linked to both SLE exposure and environmental BC risk. These findings were replicated in cancer-free twin pairs, supporting epigenetic rather than genetic mediation. SLEs may be an independent risk factor for breast cancer, potentially mediated by epigenetic mechanisms. Further research is needed to explore the functional consequences of stress-related epigenetic changes and their role in BC development across generations.

Indexed as

Breast NeoplasmsLife Change EventsStress, PsychologicalAdultAgedDNA MethylationEpigenesis, GeneticFemaleFinlandGenetic Predisposition to DiseaseHumansMiddle AgedProportional Hazards ModelsProspective StudiesRisk FactorsTwins, Monozygoticbreast cancercohort studymethylationpolygenic risk scorestressful life eventstwins

Identifiers

PMID40944570
PMCPMC12811204

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Registered trials

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Read under generation 80e0d062 · epoch 390. Bibliography from PubMed, PubMed Central and OpenAlex; grants from NIH RePORTER; trial links from ClinicalTrials.gov; estimates, votes and beliefs from the OpenQuestion graph.