BackgroundThe mechanisms responsible for the associations between very preterm birth and a higher risk of poor cardiovascular and metabolic health in adult life are unknown. MethodsComparison of the clinical and molecular phenotypes of healthy, normal weight young adults (18-27 years), born very preterm (<33 weeks gestational age (GA)) and at full-term (37-42 weeks GA).Outcomes included whole body magnetic resonance imaging; hepatic and muscle 1 H magnetic resonance spectroscopy; blood pressure (BP) measurement, urine and blood sampling and telomere length measurement. ResultsWe recruited 156 volunteers, 69 born very preterm (45 women; 24 men) and 87 born at full-term (45 women; 42 men). Preterm men had significantly more internal-abdominal adipose tissue (mean difference 0.33L (95% CI 0.04, 0.62), p<0.05), significantly fewer long telomeres (145-48.5kb: preterm men 14.1 ± 0.9%, term men 17.8 ± 1.1%, p<0.05; 48.5-8.6kb: preterm men 28.2 ± 2.6, term men 37.0 ± 2.4%, p<0.001) and a significantly higher proportion of shorter telomeres (4.2-1.3kb: preterm men 40•4 ± 3.5%, term men 29.9 ± 3.2%, p<0.01) compared to full-term men. ConclusionOur data indicate that healthy young adults born very preterm manifest clinical and molecular evidence of accelerated ageing.