Peripheral Skeletal Muscle Alterations in Adults Born Preterm: An Observational Comparative Study

Prematurity is associated with reduced exercise capacity, which relies on the integrity of the cardiovascular, pulmonary, and skeletal muscle systems. Our animal model mimicking prematurity-associated conditions showed altered muscle composition and atrophy in adulthood. This study aimed to compare muscle composition and strength in adults born preterm versus full-term controls. This observational cohort study recruited 55 adults born preterm, ≤29 weeks of gestation and 53 full-term controls who underwent musculoskeletal ultrasound imaging to assess morphology of the rectus femoris at rest and during a maximal voluntary contraction. Maximal voluntary contraction of the hands and legs were measured by manual dynamometry. In adults born preterm, there was a reduction in muscle strength (handgrip: -4.8 kg, 95% CI -9.1, -0.6; knee extensor: -44.6 N/m, 95% CI -63.4, -25.8) and muscle area (-130 mm2, 95% CI -207, -53), which was more pronounced with a history of bronchopulmonary dysplasia. Muscle stiffness was increased in the preterm group (0.4 m/s, 95% CI 0.04, 0.7). Prematurity is associated with alterations in skeletal muscle composition, area, and function in adulthood. These findings highlight the necessity to implement preventive and/or curative approaches to improve muscle development and function following preterm birth to enhance overall health in this population.