Early Life Stress, Growth, and Metabolic Health Study

By Brie ReidWith the help of 30 internationally-adopted youth (ages 9 to 18 years) and 90 youth who were matched to each internationally-adopted youth by age and body mass index (weight relative to height), we examined  metabolic and cardiovascular health with state-of-the-art technology.

Many internationally adopted children arrive in their families growth-delayed, with a significant percentage meeting criteria for height stunting (< 5% height-for-age). After adoption, most children experience catch-up growth and soon fall within age norms for height and weight.

Research suggests that the initial stunting and rapid catch-up growth can increase a child’s risk for later physical health problems. Researchers think that this is the case because in the first 1,000 days after conception, young, growing bodies determine whether the environment they are growing up in is rich or poor in nutritional resources. In this way, our bodies “calibrate” to the environment we expect to grow up in. So early physical adaptations (like height-stunting) to environments with very few resources may increase risk for obesity, metabolic syndrome, and cardiovascular disease for children who shift from resource-poor to resource-rich environments.

You might remember our earlier findings in the Puberty Study, where we found that adopted youth who were height stunted were not at an increased risk of obesity. Our group wanted to be sure that we were properly assessing all of the aspects of metabolic and cardiovascular health that are relevant to internationally-adopted children and teens. To do that, we teamed up with Dr. Aaron Kelly in the Department of Pediatrics, who specializes in cardiovascular and metabolic health, and Dr. Don Dengel in the School of Kinesiology, who specializes in high-tech measurements where fat is deposited in the body.

What did we measure?

Body composition

We measured total body fat and visceral adipose tissue (the fat around the gut) with dual X-ray absorptiometry, which was a special x-ray tool that gave us an inside look at how much fat and where fat was located. This tool also helped us measure bone mineral density. One can be thin, but still store a larger percentage of fat in the gut which increases cardiovascular risk.

Cardiovascular Health

In addition to blood pressure, we also measured arterial stiffness and heart rate variability. Arterial stiffness refers to how flexible our arteries are – we want flexible arteries because our heart has a lot of variability in how much blood it needs to pump through our body, less when we are at rest and much more when we exert ourselves physically. When our arteries are flexible, our heart can do its best job pumping blood around our body. Heart rate variability refers to the variation in the time interval between heartbeats.  A healthy heart at rest has higher variability between heart beats.

Diet & Blood Tests

Participants also filled out a food diary so we could understand how their diet might play a role in their health. We also took a blood sample to measure blood lipids, fasting glucose, and fasting insulin.

What did we find?

Compared to non-adopted children of the same age and body mass, youth adopted internationally from orphanages or institutions with a history of mild to severe height-stunting at adoption:

  • Were NOT more likely to have more overall body fat
  • Were more likely to have higher bone mineral density, but both groups had bone mineral density within normal and healthy ranges for the age group.

Versus comparison youth, youth adopted internationally with a history of height-stunting at adoption also:

  • Were more likely to have early indications of arterial stiffness, even though they were relatively lean like our comparison youth.
  • Were more likely to have a higher proportion of trunk fat.
  • Were more likely to have less lean mass overall and less lean mass in the hips, buttocks and thighs.
  • Were more likely to have higher systolic blood pressure.
  • Were more likely to have higher total cholesterol triglycerides, LDL cholesterol, and insulin.

These findings above suggest that youth adopted internationally with a history of height stunting might be at an increased risk of cardiovascular and metabolic issues later in life.

What we recommend

If your child had a history of height-stunting at adoption, we recommend talking with your health care provider about cardiovascular and metabolic health. Many of our participants had a normal BMI, and it is not typical for health care providers to screen for cardiovascular and metabolic health concerns when a young patient is not overweight or obese. Our results do not mean that your child is unhealthy, or has cardiovascular or metabolic health issues. Our results suggest that this might be something for your child to keep track of as they grow older, and talking with your child’s health care provider is the best next step.