Physical activity and body composition in Norwegian children born extremely preterm

Introduction: Extremely preterm (EP) birth is associated with a series of adverse health outcomes, some of which may be alleviated by improved physical activity (PA). Studies show diverging results regarding level of PA and bone mass density (BMD), body composition and health outcome during childhood and adult life. Aim: To examine associations between PA and body composition in a Norwegian cohort born EP compared with term-born (TB) controls. Methods: An area-based cohort of EP born children Results: Fifty preterm (22 males) and 49 controls (27 males), mean age 11.6 years, were included. The EP born children reported fewer exercise events per week and lower physical endurance during play and sports compared to their peers. The TB children were taller and had more muscle mass measured by appendicular lean mass normalized for height squared. The percentage total body fat, BMI SDs and weight SDs were not significantly different. The z-score for total BMD and total hip BMD were lower in the EP group. Low total hip BMD z-score was correlated with EP birth, low BW, female gender and less exercise. Conclusions: The EP born children were significantly less active, had less muscle mass and lower z-score for total BMD and total hip BMD compared to the controls. This implies an increased risk for later osteoporosis. EP born children’s benefit from increased PA should be further explored.