Abstract

Objective: To evaluate cardiac autonomic function in adults born preterm.

Study design: We studied the association between prematurity and cardiac autonomic function using heart rate variability measurements in 600 adults (mean age of 23.3 years) from a geographically based cohort in Northern Finland. There were 117 young adults born early preterm (<34 weeks), 207 born late preterm (34–36 weeks), and 276 born at term (≥37 weeks, controls). Autonomic function was analyzed by calculating time and frequency domain heart rate variability measurements using linear regression.

Results: Compared with controls, the mean difference in root mean square of successive differences (indicating cardiac vagal activity) was −12.0% (95% CI −22.2%, −0.5%, adjusted for sex, age, source cohort, and season P = .04) for the early preterm group and −7.8% (−16.8%, 2.0%, P = .12) for the late preterm group. Mean differences with controls in low frequency power (indicating cardiac vagal activity, including some sympathetic- and baroreflex-mediated effects) were −13.6% (−26.7%, 1.8%, P = .08) for the early preterm group and −16.4% (−27.0%, −4.3%, P = .01) for the late preterm group. Mean differences in high frequency power (quantifying cardiac vagal modulation in respiratory frequency) were −19.2% (−36.6%, 2.9%, P = .09) for the early preterm group and −13.8% (−29.4%, 5.3%, P = .15) for the late preterm group. Differences were attenuated when controlled for body mass index and physical activity.

Conclusions: Our results suggest altered autonomic regulatory control in adults born preterm, including those born late preterm. Altered autonomic regulatory control may contribute to increased cardiovascular risk in adults born preterm.