Preterm birth as a predicting factor for health and disease later in life : Growth, cardiometabolic risk, and cognitive functioning

Background and aims. Children and adults born preterm (<37 gestational weeks) are mostly healthy and live normal lives; however, preterm birth is associated with several long-term health risks. The three papers upon which this thesis is based evaluate these risks from different perspectives. Study I. Especially very preterm (<32 gestational weeks) birth is associated with cardiometabolic risks: higher blood pressure, problems at glucose and insulin metabolism, and changes in cardiac function in childhood and young adult age. We evaluated whether early nutrition or growth are associated on later cardiometabolic risks in preterm and very low birth weight (<1,500 g, VLBW) individuals. Study II. Cognitive and executive function defects among very preterm born children and adults are well established. We evaluated if adults born late preterm (34 to <37 weeks) also have cognitive or executive function deficits. Study III. Growth of preterm children differs from those born at term during the first years of life. However, not much is known about timing of pubertal growth in children born preterm. In adults born at term, early puberty is associated with higher body mass index, mental health problems, and shorter final height. We evaluated if preterm birth is associated with earlier pubertal growth compared to those born at term. Methods. Study I. The Helsinki Study of Very Low Birth Weight Adults (HeSVA) includes 166 preterm and VLBW participants born between 1978 and 1985 and treated at Helsinki University Hospital HUS. The adult assessments included measurements of blood pressure, heart rate, and lipid levels, and performance of oral glucose tolerance test (including insulin concentrations) and intravenous glucose tolerance test. To study the effects of early energy and macronutrient intakes and growth on later cardiometabolic risk factors, we used multiple linear regression models. Analyses included 125 participants who had specific nutritional data available and did not have neurosensory impairment. Study II. The ESTER preterm birth study is a cohort including 149 moderately or very preterm (