Lifetime non-relational traumatic experiences are associated with biological ageing

Exposure to non-relational trauma, such as serious accidents, war or life-threatening illness, is linked to poor mental and physical health. Its relationship with biological ageing markers, however, remains underexplored. This study's aim was to examine associations between non-relational trauma and multiple biological ageing markers, and to assess whether associations vary by trauma burden, trauma type and sex. We analysed UK Biobank data from 152,863 participants (mean age = 56.4 years; 56.5% female). Lifetime exposure to six non-relational traumatic experiences was assessed. Biological ageing markers included metabolomic age (MileAge) delta, a metabolomic mortality profile score, frailty, leukocyte telomere length and grip strength. Regression models, adjusted for demographic and socioeconomic confounders, estimated associations between trauma and biological ageing markers. We also examined trauma burden, trauma type-specific and sex-specific associations. Non-relational trauma was associated with a metabolite-predicted age exceeding chronological age (MileAge delta; β = 0.047, 95% CI 0.032-0.062), elevated metabolomic mortality scores (β = 0.102, 95% CI 0.051-0.153) and greater frailty (β = 0.298, 95% CI 0.290-0.307), with a graded, approximately linear pattern for frailty (i.e., higher non-relational trauma sum scores were associated with higher frailty scores). All trauma types were associated with greater frailty, with the strongest association for life-threatening illness. There was no evidence of associations with telomere length, and mixed findings for grip strength. Several associations differed by sex, for example overall trauma burden was more strongly associated with greater frailty in females compared to males. Lifetime non-relational trauma was associated with older biological ageing profiles, with the strongest associations with frailty. These findings support the notion that non-relational trauma exposure is associated with long-term health status, underscoring the need for mitigating ageing-related health decline in trauma-exposed populations.