Psychological and Physical Health of a Preterm Birth Cohort at Age 35 Years.

Importance: The US's longest-running preterm birth cohort study is nearing its 40th anniversary. With rising survival rates for preterm birth, understanding adult health outcomes is essential; early life medical risk trajectories are hypothesized to lead to poorer outcomes by age 35 years. Objective: To examine how early life medical risk is associated with psychological and physiological health in adulthood, highlighting the supportive roles of social protection and childhood socioeconomic status (SES). Design, Setting, and Participants: This cohort study included data from a longitudinal follow-up of a cohort from a level III neonatal intensive care unit in New England between 1985 and 1989, along with a control group of healthy full-term infants. Data were collected from March 2020 to March 2024 for the tenth follow-up using a longitudinal cohort approach. Inclusion criteria targeted preterm infants weighing under 1850 g with various neonatal diagnoses. Critically ill infants with low survival or major congenital anomalies were excluded. Biospecimens, physiological measurements, and imaging data were collected at a single clinical facility, while self-report surveys were gathered at home. Exposure: Early life medical risk from preterm birth. Main Outcomes and Measures: Primary outcomes included psychological and physiological health. Adult self-report questionnaire, blood pressure, cholesterol levels, triglycerides, glucose, glycosylated hemoglobin, insulin resistance, and dual-energy x-ray absorptiometry scan were measured. Statistical analyses included latent growth curve and path models using the medical risk index, social protection index, and SES. Results: The study sample included 158 preterm and 55 full-term-born adults (mean [SD] age, 35.0 [1.3] years; 107 [50.2%] female). Higher medical risk severity was associated with increases in internalizing problems (β [SE], 0.85 [0.33]; P = .01), higher systolic blood pressure (β [SE], 7.15 [2.47]; P = .004), lower high-density lipoprotein cholesterol (β [SE], -13.07 [4.4]; P = .003), higher triglycerides (β [SE], 53.97 [24.6]; P = .03), higher android-to-gynoid fat ratio (β [SE], 0.22 [0.08]; P = .006), and lower bone density (β [SE], -1.14 [0.40]; P = .004). Conclusions and Relevance: In this cohort study, preterm individuals had higher early life medical risk and faced increased mental health disorders, cardiometabolic issues, and body composition differences compared with full-term peers at age 35 years. Despite strong evidence linking preterm birth to long-term health consequences, many primary care clinicians in the US remain unaware of these risks, often due to infrequent birth history inquiries in adult health care settings.