Hyperinsulinemia may predict diabetes and metabolic syndrome early in young adults

"Hyperinsulinaemia in the absence of impaired glucose tolerance and normal haemoglobin A1C (HbA1c) may provide a much earlier indicator for detecting the risk of metabolic disease and progression to metabolic syndrome and diabetes mellitus," the researchers wrote.

The researchers note that HbA1c would still be a preferred marker for prediabetes diagnosis for community screening. However, people at high risk, with central adiposity, obesity, a family history of diabetes, or symptomatic (PCOS, acanthosis nigricans) should be tested for insulin resistance and hyperinsulinemia.

Hyperinsulinemia in the absence of impaired glucose tolerance and normal HbA1c indicates prediabetes. Not many Indian studies have focused on hyperinsulinemia, specifically in young adults. Rama A. Vaidya, Kasturba Health Society- Medical Research Center, Mumbai, India, and colleagues aimed to determine whether hyperinsulinemia may be present despite HbA1c being normal in a cross–sectional study.

The study was conducted on young adults and adolescents aged 16-25 living in Mumbai, India. The participants attended various academic institutions and underwent screening as the first step of a clinical trial for studying the efficacy of almond intake in prediabetes.

The study revealed the following findings:

• Among 1313 young adults, 4.2% of the participants were found to be prediabetic (ADA criteria), and 19.7% of them had HbA1c levels between 5.7%-6.4%.
• Almost 30.5% had hyperinsulinemia despite normal blood glucose levels and normal HbA1c.
• Among 533 people with HbA1c<5.7, 10.5% of participants had fasting insulin>15 mIU/L, and a higher percentage (39.4%) had stimulated insulin above 80 mIU/L. These participants had higher mean anthropometric markers than those with normal fasting and stimulated insulin.

To identify prediabetic patients, the researchers measured fasting blood glucose, HbA1c, and two h- glucose-stimulated blood glucose. In the same set of people, they measured fasting insulin and 2- h glucose-stimulated insulin. They determined how many individuals had normal HbA1c, and those who were prediabetic were hyperinsulinemia.

"Our findings revealed that as per the ADA criteria for blood glucose, only 4.2% were prediabetic, whereas 19.9% had HbA1c values in the prediabetic range (5.7% - 6.4%)," the researchers wrote. "That almost one-fifth of the young adults were prediabetic highlights the need to pay attention to this issue."

"Hyperinsulinaemia in the absence of impaired glucose tolerance and normal HbA1c may provide a much earlier indicator of detection for risk of metabolic disease and progression to metabolic syndrome and diabetes," they concluded.

Reference:

Vaidya, R. A., Desai, S., Moitra, P., Salis, S., Agashe, S., Battalwar, R., Mehta, A., Madan, J., Kalita, S., Udipi, S. A., & Vaidya, A. B. (2023). Hyperinsulinemia: An early biomarker of metabolic dysfunction. Frontiers in Clinical Diabetes and Healthcare, 4. https://doi.org/10.3389/fcdhc.2023.1159664