Published March 2016
Diabetes Care

When obesity gets worse for teens with type 1 diabetes, their carotid arteries get thicker and their risk of suffering a heart attack or stroke later in life rises.

However, other known heart disease risk factors, including smoking, high blood pressure and high hemoglobin A1c levels, do not appear to impact carotid artery thickness.

These findings underscore Body Mass Index Z-scores (BMIz), as a potentially modifiable risk factor for heart disease for children with type 1 diabetes. Unlike standard BMI measures for adults, BMIz scores show how body mass deviates from the norm as children grow.

“We found body mass index emerged as the only factor associated with a thicker carotid artery," says senior author, Elaine Urbina, MD, MS, director of Preventive Cardiology at the Heart Institute.

"This suggests that considerably more study is needed to fully understand the connections between childhood diabetes and heart disease.”

Urbina, first author Amy Shah, MD, MS, in the Division of Endocrinology, and several colleagues in the SEARCH for Diabetes in Youth Study evaluated 298 children with type 1 diabetes to measure how heart disease risk factors changed over five years. The team evaluated BMIz, lipids, blood pressure, hemoglobin A1c, and smoking status. They also used ultrasound to measure the carotid artery.

After five years, 53 percent of participants showed signs of two or more heart disease risk factors, a clear increase over baseline. The one change that showed statistically significant impact: 34 percent of children demonstrated high BMIz scores after five years, up from 27 percent when the study began.

Previous studies led by Urbina and Shah established that youths with type I diabetes can show surprising early signs of atherosclerosis. “Our new findings indicate that controlling obesity may be one of the most impactful approaches for minimizing heart disease risk for these children,” Shah says.