Six-year-old Triniti LaBoard, a participant in a new VCH study, hugs her twin brother, Kymet, on their front porch in North Nashville.
photo by Dana Johnson
Researchers seek childhood predictors for heart disease
There may be signs present early in life that set some people apart as being at higher risk for health problems linked to obesity, researchers at the Monroe Carell Jr. Children's Hospital at Vanderbilt theorize.
Revi Mathew, M.D., associate professor of Pediatrics, is looking for children under the age of 9 to tease out early indicators of heart disease he feels may be present in some children even before they're old enough to go to school. He is focusing on a particular group of children with a little known condition called premature pubarche.
Over the years, Mathew has noticed an increasing number of children being referred to the Pediatric Endocrinology practice for this condition, which mimics premature or early puberty. The hallmark of premature pubarche is the growth of hair in the pubic area and underarms before age 9 in boys and 8 in girls. Signs of premature pubarche can be seen in children as young as 3.
“This is not related to early puberty, nor is it related to hereditary problems of the adrenal glands that can cause similar symptoms, or androgen-producing tumors,” Mathew said. “But it does appear to be correlated with insulin resistance and sometimes obesity. With this study, we want a closer look at the correlation of premature pubarche with future heart and blood pressure problems and even find ways to reliably diagnose and prevent future morbidity.”
There is a suggestion that premature pubarche is related to an increased risk of developing metabolic syndrome, or “Syndrome X,” later in life. Syndrome X is a constellation of health problems that seems to describe the stereotypically unhealthy American — overweight, with a tendency to develop high blood pressure, type 2 diabetes and clogged arteries.
With or without the stereotype, current research indicates a pattern that is traceable back to childhood. Now, Mathew would like to find out if children with premature pubarche are among those with the strongest tendencies to develop health problems linked with obesity.
In a small pilot study, Mathew found an association between premature pubarche and several indicators: a significant decrease in a blood chemical called adiponectin (low adiponectin levels indicate insulin resistance); an increase in diastolic blood pressure; and body fat. His new study will be larger and will look for differences between children with premature pubarche and those without it. Tests will record blood cholesterols, bone density, insulin sensitivity, clotting tendencies, levels of certain sex hormones, thickness of the carotid artery wall and radial artery tone.
“We have studied nearly 20 children with premature pubarche and we are matching them with controls who have a similar body size, age, ethnicity and are of the same sex,” Mathew said.
Once a baseline is determined for children with and without premature pubarche, only the children with the disorder will have repeated testing for a number of years.
Kim LaBoard's 6-year-old twins, Triniti and Kymet, are part of the study. Triniti has signs of the disorder, while Kymet does not.
“We have a lot of obesity in my family, and when Triniti was already growing taller than her twin brother I figured it was genetic,” said LaBoard. “Our primary care provider was concerned about Triniti's early growth of pubic hair, so when she found out about this study, she suggested we enroll.”
“This has a more dramatic affect on girls,” Mathew said. “Premature pubarche is 10 times more common in girls than boys.”
It is already known that the condition leads to an increase in male hormones and that later in life 45 percent to 50 percent of the girls with premature pubarche develop polycystic ovary syndrome, a major cause of infertility in the United States.
“We hope to find out if we can identify early indicators in this group of children with premature pubarche,” Mathew said. “If we can do that, it is possible that lifestyle changes, like increased activity and a healthier diet, might prevent other health problems like PCOS or Syndrome X from developing. ”
To be part of the study, children must:
• Be an African-American female between the ages of 3 and 6;
• Be a Caucasian-American female between the ages of 4 and 8;
• Be an African-American or Caucasian male between the ages of 4 and 9.
If selected, children will visit the Clinical Research Center or the Children's Hospital three times to have blood drawn, to get body measurements and to have X-rays and ultrasounds. For more information, contact Connie Sanderson, R.N., at 835-5241 or e-mail EndoStudy@Vanderbilt.edu.