Source: [pubmed](https://pubmed.ncbi.nlm.nih.gov/42196441/)
Authors: La Grotta R, Crocco P, Leonova A, Dato S, Passarino G
Venue: Int J Mol Sci · 2026 May 16
AI relevance (4/5): Telomere length as chronic stress biomarker in aging cohort; mechanistic link to allostatic load operationalized.
As people age, they often develop multiple chronic diseases simultaneously — a phenomenon called multimorbidity. This study investigated whether the length of telomeres (protective caps on chromosomes that shorten with biological aging and cumulative stress) is linked to how many conditions an older person carries. Using a cohort of older adults, the researchers found that shorter relative leukocyte telomere length (rLTL) was associated with a greater multimorbidity burden, suggesting that biological aging at the cellular level tracks with disease accumulation. Critically, the associations were not the same in men and women — sex-specific patterns emerged, pointing to different biological or hormonal pathways shaping telomere dynamics across the lifespan. This matters because telomere length is increasingly viewed as an integrative biomarker of allostatic load: the cumulative 'wear and tear' that chronic stress, inflammation, and lifestyle impose on the body. The findings position rLTL as a potentially useful, measurable index of biological age in clinical and epidemiological research on aging populations. Understanding why the sex-specific differences exist could open doors to tailored prevention strategies for age-related disease accumulation.
This was a cross-sectional observational study conducted in a cohort of older adults. Relative leukocyte telomere length (rLTL) was measured from blood samples using quantitative PCR or comparable molecular methods. Multimorbidity was operationalized as the count or index of concurrent chronic conditions per participant. Sex-stratified analyses were performed to detect differential associations between rLTL and multimorbidity burden in men versus women.
The cross-sectional design prevents causal inference — it is impossible to determine whether shorter telomeres precede multimorbidity, result from it, or whether both are driven by shared upstream factors such as inflammation or socioeconomic adversity. The study cannot rule out reverse causation or survivor bias common in older-adult cohorts, where the most biologically worn individuals may not survive to enrollment. Residual confounding by lifestyle factors (diet, physical activity, smoking history) and socioeconomic variables may partially explain the associations. A longitudinal follow-up measuring rLTL at multiple timepoints alongside incident disease would be the key next experiment to establish temporal directionality and predictive validity.
This study extends [§106], which also examines telomere length as a biomarker of cumulative physiological stress but in pregnant women exposed to endocrine disruptors — together the two articles bracket the lifespan, showing rLTL as a stress-sensitive index at both early and late life stages. It parallels [§67], which traces how stress exposures during the first 1,000 days of life embed in biological aging trajectories, providing a developmental complement to the present findings in older adults. The sex-specific associations reported here are particularly relevant alongside [§107], which examines allostatic load and breast carcinoma risk in the UK Biobank and similarly implicates sex as a biological moderator of cumulative stress-disease relationships. The mechanistic framing — rLTL as a readout of allostatic load rather than a single-stressor marker — also resonates with [§93], which links periodontal inflammation to allostatic load and underscores how multi-system stress signals converge on shared biological aging indices.
