Study Identifies Link Between Prediabetes in Adolescence and Young Adulthood and the Likelihood of an Unfavorable Pregnancy Outcome

Researchers at Mount Sinai have published a study showing an association between prediabetes in young people and adverse pregnancy outcomes later in life. The findings, published in JAMA Network Open, could change the way doctors routinely screen for or counsel on blood sugar levels in adolescents, and subsequently minimize potential risks to both mother and child.

Prediabetes Before Conception More Than Twice as Likely to be Associated With Gestational Diabetes

Prediabetes is a serious condition that occurs when blood sugar levels are higher than normal but not high enough to be diagnosed as type 2 diabetes, or when blood sugar levels are persistently high. Prediabetes can increase the risk of heart disease and stroke and disproportionately impacts Hispanics, blacks, and those with low income. The rate of prediabetes among adolescents in the United States has doubled in the last decade and affects nearly one in three adolescents aged 12 to 19 years, according to JAMA Pediatrics.

In their new study, Mount Sinai researchers examined the importance of pre-conception prediabetes in adolescents and young adults, a group most at risk for unplanned pregnancy and least likely to benefit from pre-conception health counseling. The retrospective cohort study of more than 14,000 individuals aged between 10 and 24 years was conducted by linking data from the New York City birth registry, hospital discharge records, and the A1C registry between 2009 and 2017. The study included individuals who had never had diabetes before their first birth and had at least one hemoglobin A1c (HbA1c) test.

The researchers found that prediabetes before conception was associated with more than double the likelihood of gestational diabetes in a future first birth. The experts found that prediabetes in adolescence and early adulthood can lead to an 18 percent increased risk of hypertensive disorders during pregnancy, such as gestational hypertension and preeclampsia or premature birth.

The study also examined which hemoglobin A1c level, a measure of a person’s average blood sugar level over the past three months, in adolescents and young adults best indicates gestational diabetes in the first birth. The optimal threshold was slightly lower in young people than in adults (5.6 percent vs. 5.7 percent). Overall, the study results underscore the need to establish clear clinical guidelines for the examination and counseling of young people with currently elevated blood glucose levels without other risk factors, according to the researchers.

Interventions to Reduce the Risk of Heart and Metabolic Disease in Adolescence

The lack of uniform guidelines for managing prediabetes in adolescents prior to conception may represent a missed opportunity to avert pregnancy-related complications, according to corresponding author Katharine McCarthy, PhD, MPH, assistant professor of population health sciences and policy and obstetrics, gynecology and reproductive sciences at the Icahn School of Medicine at Mount Sinai. These findings support expanded hemoglobin A1c screening prior to conception as a mechanism to intervene earlier in the life course on excess cardiometabolic risk, according to the researchers. Next, the experts will explore possible school policies and interventions that could reduce the risk of heart and metabolic disease in adolescence and positively impact pregnancy and health across the life course.

The Dangers of Prediabetes

Intensive lifestyle intervention with a lot of physical activity helps people with prediabetes to improve their blood sugar levels over a period of years, thus delaying or even preventing type 2 diabetes. In particular, individuals with prediabetes at highest risk benefited from intensive lifestyle intervention. More exercise and a healthy diet help many people with prediabetes to normalize their blood sugar levels and avoid the development of type 2 diabetes. However, not everyone benefits from conventional lifestyle intervention (LI).

Studies show that there are already various subtypes with different risk profiles in prediabetes. Researchers at the German Center for Diabetes Research (DZD) have therefore conducted a multicenter randomized controlled study to determine whether people with prediabetes and high risk benefit from an intensification of the intervention and how people with low risk benefit from a conventional lifestyle intervention compared to no lifestyle change. The lifestyle intervention lasted 12 months in each case, with a follow-up period of a further two years. A total of 1,105 people with prediabetes were examined at various study centers in Germany and assigned to a high- or low-risk phenotype based on insulin secretion, insulin sensitivity and liver fat content. 82% of the participants completed the study.

More Exercise Improves Blood Sugar and Cardiometabolic Values

High-risk individuals – those who produce too little insulin or have fatty liver with insulin resistance – were randomly assigned to receive either conventional LI as per the Diabetes Prevention Program (DPP) or a more intensive intervention with double the amount of exercise required. The results showed that more exercise, i.e. more intensive LI, helps people at high risk to improve their blood sugar and cardiometabolic values and to reduce liver fat to a normal level.

Conventional LI is less effective. Participants at low risk completed conventional LI or participated in a control group that received only a one-time brief consultation. After three years, glucose tolerance had normalized more in the conventional lifestyle intervention group than in the control group. There was little difference in insulin sensitivity and secretion, liver fat content, and cardiometabolic risk. The study results show that an individualized lifestyle intervention based on the risk phenotype is beneficial for diabetes prevention.