Increased Fasting Blood Glucose Triples Risk of Heart Damage in Adolescents

A recent study conducted collaboratively between the US, Switzerland, Australia, Finland, and the UK indicated that high blood sugar and insulin resistance substantially increase the risk of heart failure in adolescents, particularly females.1

Heart failure often results from existing conditions, such as type 2 diabetes mellitus. Insulin resistance has often been cited as a key pathogen in diabetes-related cardiac dysfunction. However, few studies have provided conclusive findings on the connection between insulin resistance and incident heart failure.2

“Worsening insulin resistance and increased fat mass have a bidirectional reinforcing vicious cycle,” said Andrew Agbaje, MD, MPH, PhD, physician and associate professor at the University of Eastern Finland. “In the new study, we observed that two-thirds of the effect of insulin resistance on excessive heart enlargement was explained by increased total body fat.”1

Agbaje and colleagues collected data on 1595 adolescents, drawn from the University of Bristol’s Children of the 90s cohort. They were followed up from age 17-24. Investigators assessed the prevalence of prediabetes by measuring fasting blood glucose levels. Two cutpoints were used: ≥5.6 mmol/L, recommended by the American Diabetes Association, and ≥6.1 mmol/L, recommended by many countries.1

At the 17-year follow-up, 6.2% of adolescents had a fasting blood sugar ≥5.6 mmol/L. This number increased almost five times by age 24, with 26.9% exhibiting this glucose level. Only 1.1% had ≥6.1 mmol/L, which also increased fivefold to 5.6% at age 24. Excessive heart enlargement, particularly left ventricular hypertrophy, tripled from 2.4% at 17 years to 7.1% at 24 years. Prevalence of heart dysfunction rose from 9.2% to 15.8% over the same time frame.1

The team noted that persistent fasting blood sugar ≥5.6 mmol/L between ages 17 and 24 was associated with a 46% increased risk of left ventricular hypertrophy. This risk was threefold if fasting blood sugar was consistently ≥6.1 mmol/L. High blood sugar also decreases heart muscle relaxation, alters normal function, and increases the pressure of incoming blood flow to the heart.1

Similarly, insulin resistance was associated with a 10% increase in risk of premature heart damage. During the 7-year growth period, glucose levels added .57 g/m2.7 to cardiac mass increases in females compared to a .11 g/m2.7 growth in males.1

Earlier adult-focused studies have indicated that high blood sugar and insulin resistance in youth significantly predict the risk of type 2 diabetes mellitus in mid-50s adults. Additionally, the younger one is when diagnosed with type 2 diabetes, the more severe and rapid the complications may be when left untreated.1

Interestingly, however, no prior studies have examined the earliest manifestation of consequences of high blood sugar and insulin resistance on the heart. This is likely due to the lack of repeated echocardiography assessments in healthy youth.1

Agbaje and colleagues noted that this study is the largest and longest follow-up of glucose concentration and repeated echocardiography study in a relatively healthy young population. In addition to fasting glucose and insulin, investigators examined low-density lipoprotein cholesterol, high-density lipoprotein cholesterol, triglycerides, and high-sensitivity C-reactive protein.1

“Earlier results from the same cohort indicate that late adolescence is a critical period in the evolution of cardiometabolic diseases,” said Agbaje. “The current findings further confirm that even healthy-looking adolescents and young adults who are mostly normal weight may be on a path towards cardiovascular diseases, if they have high blood glucose and insulin resistance.”1

References

1. 1: University of Eastern Finland. High blood sugar in adolescence tripled the risk of premature heart damage affecting females worse than males. EurekAlert! April 28, 2025. Accessed April 28, 2025. https://www.eurekalert.org/news-releases/1081588?

2. 2: Erqou S, Adler AI, Challa AA, Fonarow GC, Echouffo-Tcheugui JB. Insulin resistance and incident heart failure: a meta-analysis. Eur J Heart Fail. 2022;24(6):1139-1141. doi:10.1002/ejhf.2531