Preterm Birth Predicts Adult Health Problems

Adults born preterm were significantly more likely to have cardiometabolic risk factors and internalized mental health issues than full-term peers, according to an ongoing preterm birth cohort study in the US.

“This study addresses a significant gap in understanding the long-term health effects of preterm birth in the US,” said lead author Amy D’Agata, PhD, of the College of Nursing, The University of Rhode Island, Kingston, Rhode Island, in an interview.

Although the annual preterm birth rate in the US has held at a relatively stable 10%-12% for decades, since the 1970s, more preterm infants are surviving because of advances in neonatal intensive care, D’Agata said. Millions of individuals born preterm are aging into adulthood, but few data are available on their long-term health outcomes, she noted.

In the new study, published in JAMA Network Open, D’Agata and colleagues reviewed data from a cohort of individuals who received level III neonatal intensive care at a single center between 1985 and 1989. The study population included 158 preterm-born and 55 full-term born adult control individuals.

Preterm was defined as weighing under 1850 g at birth with various neonatal diagnoses; critically ill infants and those with major congenital abnormalities were excluded. The mean age across the groups was 35 years; 50% were women. The researchers used latent growth curve models to show changes over time.

Overall, the preterm individuals who had higher medical risk in early life were significantly more likely to have a range of health problems at 35 years of age, notably, higher triglycerides than control individuals (beta value, 53.97; P = .03).

Measures of systolic blood pressure and central adiposity also were significantly higher in the preterm birth group (beta values of 7.15 and 0.22, respectively), whereas bone density and high-density lipoprotein cholesterol were lower (beta values of -1.14 and -13.07, respectively).

In addition, internalizing mental health problems were significantly more common in the preterm cohort than in the control individuals (beta value, 0.85; P = .01) but no difference in externalizing mental health problems was noted between the groups.

The researchers also reviewed the impact of social protection and childhood socioeconomic status and found no association between these and physical or psychological health risks in adults born preterm.

The Long View of Preterm Birth

The population of adults born preterm remains largely invisible to the US healthcare system and its clinicians, highlighting critical issues of health equity and quality of care, D’Agata told Medscape Medical News.

“Much of the existing research in this area has focused on international, homogeneous populations, creating a need for rigorous, US-based longitudinal data to guide healthcare policy and clinical practice,” she added.

“These findings generally confirmed what has been observed internationally, that there is a link between higher early life medical risk and increased likelihood of mental health issues, elevated systolic blood pressure, unfavorable cholesterol and triglyceride levels, body fat distribution, and lower bone density among adults born preterm, and it was notable to see these clear and consistent associations replicated in a US cohort using a prospective, longitudinal design,” said D’Agata.

The study findings emphasized the need to inquire about birth history in adult care settings and suggest that those born preterm and their families must be their own health advocates, if necessary, said D’Agata. “Even if a patient isn’t asked about their birth history, they should share it,” she noted. Clinicians work hard to provide the best care, but it takes time for evidence-based research to inform clinical practice, she said.

“Although our birth cohort is small and comes from a single geographic region, the results generally align with international findings,” D’Agata told Medscape Medical News. However, future studies should include more racially and ethnically diverse cohorts from multiple clinical settings, she said. Research is needed not only to examine which subgroups of preterm individuals are most at risk but also to differentiate between those with varying degrees of early life complications, she added.

Long Follow-Up Strengthens Findings

The 35-year duration of the preterm birth cohort study was impressive and valuable, said Tim Joos, MD, a clinician with a combination internal medicine/pediatrics practice at Neighborcare Health in Seattle. “We don’t often have the long game in mind, in healthcare as well as in other parts of our society,” said Joos, who was not involved in the study. “We don’t tend to follow pediatric conditions into adulthood,” he noted.

The current study findings demonstrated a long-term psychological and physical impact of prematurity on adult health that was humbling, Joos told Medscape Medical News. Looking ahead, the results highlight not only the need to continue to prevent preterm birth but also to the importance of asking older patients about preterm birth as part of their health history, he said.

This study was funded by the National Institute of Nursing Research of the National Institutes of Health. D’Agata disclosed no financial conflicts of interest. Joos disclosed no financial conflicts of interest.