Medical issues and neighborhood opportunity can affect infant development
Top photo: Philip Mroz/Unsplash
CU Boulder researcher Emily Yeo finds that some babies may benefit from more support and resources so they can grow up to lead long, happy and healthy lives
In an ideal world, every baby would be born perfectly healthy. Unfortunately, many newborns arrive prematurely or suffer from medical conditions that could hinder their future development.
Some of these high-risk infants live in neighborhoods with access to healthy food, low crime rates and affordable housing. Others, however, live in worse-off communities with limited access to quality education, health care, housing and jobs.
Now, new research led by CU Boulderās Emily Yeo explores how medical complexity and neighborhood opportunity might affect the development of high-risk infants.

Emily Yeo, a PhD student in the CU Boulder Department of Integrative Physiology, led research exploring how medical complexity and neighborhood opportunity might affect the development of high-risk infants.
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The findings, recently published in the , suggest some babies may benefit from more support and resources so they can grow up to lead long, happy and healthy lives.
āWhat the study highlights is that thereās sort of a double burden on medically complex infants living in lower-opportunity neighborhoods,ā says Yeo, a doctoral student in the Department of Integrative Physiology. āThere needs to be a lot more research into how we can better support these infants, especially within the first couple of years of their lives, which are critical for development and when small interventions could have a huge, life-long impact.ā
Studying high-risk infants in California
Public health professionals have long understood that social, environmental and economic factors affect human health and development. Everything from a personās income and education levels to the purity of the air they breathe and their access to grocery stores can play a role in their well-being.
Against this backdrop, scientists wanted to understand whether there was a relationship between the complexity of infantsā medical conditions, their neighborhood opportunity and their developmental progress.
āTo fully understand the developmental challenges these infants face, it is essential to consider how their medical conditions interact with the social and environmental contexts of their upbringing,ā says Yeo.
The team studied 440 infants born in Southern California between 2014 and 2023. Doctors had deemed these babies āhigh-riskā because they were born prematurely, had very low birth weights or suffered from conditions that required treatment in a neonatal intensive care unit.
By reviewing the infantsā medical records, scientists were able to categorize them based on the seriousness of their situation. Infants with the highest level of medical complexity, for instance, had conditions like permanent brain damage or chronic respiratory issues. Those with the lowest level of medical complexity, meanwhile, had more easily treatable conditions, like acute lung or eye infections.
Researchers also assessed each childās neighborhood opportunity level, based on their home address. For this, they turned to the , a pre-existing, composite index that analyzes education, health, social and economic data from every census tract in the United States.
Some neighborhoods earn high scores, because the children who live there have access to quality schools, clean air, health care, playgrounds and other conditions that will help them grow up healthy and become thriving adults. Other neighborhoods, however, offer very few or none of these resources. Black, Hispanic and Native American children are more likely to live in very low-opportunity neighborhoods compared to their White peers.
For each child, researchers also collected developmental scores from standard tests conducted when they were between the ages of 4 months and 36 months old. The scores came from the Bayley Scales of Infant and Toddler Development, which doctors consider the āgold standardā for evaluating infant cognitive, motor and language skills, the researchers write in the paper.
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CU Boulder researcher Emily Yeo found that childhood development is affected by both medical and social factors, which aligns with what pediatricians see in daily practice. (Photo: Emily May/Unsplash)
When the scientists analyzed all of the data they had gathered, some clear patterns began to emerge. Developmental scores got worse as medical complexity increased, meaning that infants with more severe and complicated health conditions had lower cognitive, motor and language scores.ĢżThese finding are consistent with previous studies, says Yeo, which have found that infants with fewer medical complications are also likely to face fewer challenges achieving growth milestones.
The study also found that medical complexity had a more significant effect on developmental outcomes than gestational age, or how early a baby was born. This is an important takeaway for pediatricians, who have long used gestational age to predict potential developmental delays or issues, says Yeo.
āGestational age might be useful for infants who are not medically complex, but if youāre looking specifically at those infants, we need a more granular tool,ā she says. āWith this group of infants, we saw that gestational age didnāt really play a huge role in deciphering differences in development, whereas their degree of medical complexity did.ā
The researchers also found a correlation between lower neighborhood opportunity scores and decreased language scores, but not cognitive and motor scores. The reasons for this discrepancy are not clear. But, overall, this finding indicates that where an infant lives does seem to play a role in their development.
Importantly, the study also ruled out differences in development based on race and ethnicity alone. Black and Hispanic babies did have lower developmental scores than White babies, but the findings indicate those disparities resulted from differences in the infantsāĢżsocio-demographic and medical factors.
āThe differences do not come from race and ethnicity itselfāthey come from other influential factors that tend to be worse in those groups,ā says Yeo, adding that this finding aligns with the general shift from race-based to race-conscious medicine.
More social supports for development
Together, the study results align with what pediatricians see in real lifeāthat childhood development is affected by both medical and social factors. The research also highlights the importance of early intervention programs and policies designed to help children succeed.
āItās one more indication of how, if we really want to move the needle and improve the outcomes of these babies that are born with medical risk factors, we need to put as many social supports in place as we can to support their development,ā says study senior author , a pediatrician at Childrenās Hospital Los Angeles and an associate professor of clinical pediatrics in the Keck School of Medicine at the University of Southern California.
āItās not just the childās medical diagnosis that is going to impact their developmentāitās also the neighborhood the child is brought up in, how much medical care their family is able to afford and other barriers.ā
The study did not explore the possible mechanisms at playāthat is, why medical complexity and neighborhood opportunity seem to be linked with development. But the researchers have a few theories.
For one, children with very serious health issues often need to use medical equipment that helps them breathe and eatālike feeding tubes in their stomachs or oxygen tubes in their noses. From a purely physical standpoint, these devices may make it difficult for infants to do āall the basic things babies do,ā Mirzaian says, like rolling around or pulling themselves up to a standing position.
Another possible explanation is that a childās appointments and treatments may leave little time for activities that promote development, like reading and playing with toys, Mirzaian adds.
Families living in neighborhoods with low opportunity scores, meanwhile, may be grappling with povertyāand having a baby with a serious medical condition likely only adds to their stress. Through no fault of their own, caregivers may need to focus more on basic needsālike how theyāre going to pay next monthās rent or put food on the tableāand less on their childās development, says Mirzaian.
āMedical Data Alone Does Not Tell the Whole Storyā
Looking ahead, the co-authors hope other researchers will repeat and replicate the study, perhaps in other geographic locations or with slightly different populations. Future work might also involve following the same children as they grow up, to see whether and how their developmental outcomes change over time.
For now, though, the study is a good first step toward understanding the link between medical complexity, neighborhood opportunity and development. Zooming out, the findings also reinforce the idea that āmedical data alone does not tell the whole story,ā says Yeo.
āItās important for researchers to consider social explanations to formulate a holistic picture of infant development,ā she adds. āItās not just the childās medical diagnosis that is going to impact their developmentāitās also the neighborhood the child is brought up in, how much medical care their family is able to afford and other barriers.ā
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