Telomere length as a marker of biological age in paediatric multiple sclerosis

Increased chronological age correlates with reduced relapse rates and increased disability in multiple sclerosis (MS). Biological age may better capture ageing's impact on MS and might accelerate due to MS itself. Establishing accelerated biological ageing in adults is complicated by normal ageing and comorbidities. Telomere length, a well-recognised biological ageing marker, is shortened in adults with MS and associated with disability. Demonstrating accelerated biological ageing in paediatric-onset MS (POMS) would strengthen the hypothesis that MS drives premature biological ageing. This study aimed to determine if telomere length differs in POMS compared to age-similar healthy controls.

We performed a cross-sectional case-control study of whole blood samples and clinical data from The US Network of Pediatric MS Centers. Real-time quantitative PCR measured telomere length, expressed as a telomere to somatic DNA ratio (T/S ratio). T/S ratio was compared between cases and age-similar healthy controls using multivariate regression analysis adjusting for chronological age, sex, race, ethnicity, tobacco exposure, socioeconomic status and body mass index.

We analysed 300 POMS cases and 200 controls. The unadjusted mean T/S ratios were 1.66 (SD 0.32) for cases and 1.71 (SD 0.29) for controls (mean difference -0.05, 95% CI -0.10 to 0.01, p=0.08). After adjusting for key covariables with face validity, POMS participants had a mean 0.086 shorter T/S ratio than controls (95% CI 0.015 to 0.157, p=0.018).

POMS participants demonstrated shorter telomeres than age-similar controls in a multivariable model adjusting for sociodemographic variables, suggesting that MS may contribute to accelerated biological ageing.