Clinicians have known that individuals who are born preterm—after less than 37 weeks of gestation—are more likely to die in early childhood, but less is known about the long-term health effects of preterm birth. New findings appearing today in JAMA have found that although the increased risk of death associated with preterm birth disappears in older childhood, it reappears in young adults, after age 18 years.
In the study, researchers led by Casey Crump, MD, PhD, of Stanford University in Stanford, Calif, examined records from a national study of 674 820 people (including 27 979 delivered preterm), who were born in Sweden from 1973 through 1979 and were followed up through 2008. A total of 7095 deaths occurred during that time, 2903 among those born preterm. Not surprisingly, early childhood death (most often due to congenital defects and endocrine and respiratory disorders) was associated with preterm birth. Those born preterm also were more likely to die as young adults, due to the same conditions, as well as cardiovascular disorders.
Lead author Casey Crump, MD, PhD, comments on his team’s findings:
“Early mortality and morbidity for those born preterm has been extremely well-known, and previous evidence suggests that once you survived that period, you did relatively well in late childhood and adolescence. So it appeared the risk waned over time. Our research showed for the first time that the risk does not wane, with increased mortality in young adulthood being associated with preterm birth.
“It appears that some of the causes of death in young adulthood have long latency periods. An important outcome of our research should be to improve awareness among preterms and their physicians of these long-term health effects. It should be important for those born preterm to avoid other risk factors to offset or prevent these risks we found.
“Preterms born today may have different outcomes from the cohort we studied because of the advances in neonatal care, but it is unclear what the long-term outcomes may be. They could be better or worse. The health care delivered today is better than it was in the 1970s, which should benefit preterms. But today, [more individuals are surviving earlier] preterm births and this could in fact amplify risks.”