Researchers studied over 11,600 American adults to understand how the body’s difficulty controlling blood sugar relates to heart disease risk. They found that people with higher insulin resistance—meaning their bodies don’t respond well to insulin, the hormone that controls blood sugar—were more likely to have heart disease. The study identified specific measurements that doctors can use to predict who might be at higher risk. One measurement called TyG-WHtR (which combines triglycerides, glucose, and waist size) was the best at predicting heart disease risk. These findings could help doctors catch people at risk earlier and help them make changes to prevent heart disease.

The Quick Take

  • What they studied: How problems with the body’s ability to control blood sugar (insulin resistance) connect to heart disease risk in adults
  • Who participated: 11,687 American adults from a national health survey conducted between 2007 and 2016, representing a diverse population
  • Key finding: About 9 out of every 100 people studied had heart disease. People with higher insulin resistance measurements had significantly higher chances of having heart disease, especially when certain measurements crossed specific thresholds. One measurement (TyG-WHtR) was better at predicting heart disease than the others.
  • What it means for you: If you have difficulty controlling your blood sugar or are overweight, getting your insulin resistance checked might help identify your heart disease risk early. This could motivate you to make lifestyle changes like exercising more or improving your diet. However, these findings are from one study and should be discussed with your doctor.

The Research Details

This was a cross-sectional study, which means researchers looked at a large group of people at one point in time and collected information about their health. They used data from the National Health and Nutrition Examination Survey, a well-known government health study that has been tracking Americans’ health for decades. The researchers measured four different ways to assess insulin resistance (how well the body handles blood sugar) and checked which people had heart disease. They then used statistical methods to see if higher insulin resistance measurements were connected to higher rates of heart disease.

The researchers were careful to account for other factors that might affect heart disease risk, like age, smoking, exercise habits, and whether someone had diabetes. They also looked for patterns—specifically, they checked if the relationship between insulin resistance and heart disease was straight (linear) or curved (nonlinear), meaning the risk might jump up suddenly at certain levels.

They also tested whether the results held true for different groups of people, like those with and without diabetes, and those who exercise versus those who don’t. Finally, they compared how well each of the four measurements predicted heart disease risk.

This research approach is important because it uses real-world data from thousands of Americans rather than just laboratory studies. By looking at actual people and their health outcomes, the findings are more likely to apply to everyday life. The study’s large size and careful statistical methods make the results more reliable than smaller studies. Understanding which measurements best predict heart disease risk helps doctors identify people who need help before they have a heart attack or stroke.

This study has several strengths: it included a large, diverse group of Americans, used well-established health measurements, and carefully controlled for other factors that might affect results. However, because it’s a cross-sectional study (a snapshot in time), it can show that two things are connected but can’t prove that insulin resistance actually causes heart disease. The study used data from 2007-2016, so some information is somewhat dated. The researchers were transparent about their methods, which is a good sign of quality.

What the Results Show

Among the 11,687 people studied, about 9.4% (roughly 1 in 11) had heart disease. The researchers found that one measurement of insulin resistance called METS-IR showed a straight-line relationship with heart disease—the higher the METS-IR, the higher the heart disease risk.

However, three other measurements showed curved relationships, meaning the risk didn’t increase steadily. For the TyG measurement (which looks at triglycerides and glucose), when the number went above 9.03, it was connected to a 31% higher risk of heart disease compared to lower levels. For HOMA-IR (another insulin resistance measure), the risk increased up to a level of 6.79, then the increase slowed down.

The most important finding was about TyG-WHtR (which combines triglycerides, glucose, and waist-to-height ratio). When this number exceeded 5.82, people had a 32% higher risk of heart disease, and the risk kept climbing as the number got higher. This measurement was the best at predicting who had heart disease compared to the other three measurements.

The study also found that the connection between insulin resistance and heart disease was stronger in people with diabetes and in those who didn’t exercise regularly.

The researchers discovered that physical activity level made a difference in how insulin resistance affected heart disease risk. People who were physically active had a weaker connection between insulin resistance and heart disease, suggesting that exercise might protect against heart disease even when insulin resistance is present. The relationship between insulin resistance and heart disease was also different depending on whether someone had diabetes, indicating that diabetes status is an important factor to consider.

Previous research has suggested that insulin resistance is connected to heart disease, but this study helps clarify which measurements work best for predicting risk. The finding that TyG-WHtR is the strongest predictor is relatively new and suggests that combining information about blood fats, blood sugar, and body shape gives doctors better information than looking at any single measurement alone. The study confirms what other research has suggested: that insulin resistance is an independent risk factor for heart disease, meaning it increases risk even when accounting for other known risk factors.

This study has several important limitations. First, it’s a snapshot in time, so it shows that insulin resistance and heart disease are connected, but it can’t prove that insulin resistance causes heart disease. Second, the data is from 2007-2016, so it’s somewhat dated and may not reflect current American health patterns. Third, the study only included Americans, so the results might not apply to other populations. Fourth, the measurements of insulin resistance are indirect—they estimate how well the body handles insulin rather than measuring it directly. Finally, the study couldn’t account for all possible factors that might affect heart disease risk, such as family history or stress levels.

The Bottom Line

If you have risk factors for insulin resistance (such as being overweight, having high blood sugar, or having high triglycerides), talk to your doctor about getting your insulin resistance checked. The evidence suggests moderate confidence that improving insulin sensitivity through exercise and diet changes may help reduce heart disease risk. Specifically, aim for at least 150 minutes of moderate exercise per week and work with a nutritionist on dietary improvements. These recommendations are supported by this study and broader heart disease prevention guidelines.

This research is most relevant for adults who are overweight, have high blood sugar or diabetes, have high triglycerides, or have a family history of heart disease. It’s also important for doctors and healthcare providers who want to better identify patients at risk for heart disease. People with normal weight and good blood sugar control should still maintain healthy habits but may have lower immediate risk. Anyone with existing heart disease should work closely with their cardiologist rather than relying solely on these findings.

If you make lifestyle changes based on these findings, you might see improvements in your insulin resistance and related measurements within 3-6 months. However, significant reductions in heart disease risk typically take longer—usually 1-2 years of consistent healthy habits. Some people may see benefits sooner, while others may take longer. It’s important to work with your doctor to monitor your progress.

Want to Apply This Research?

  • Track your waist circumference monthly and log your triglyceride and glucose levels (if you have access to testing) every 3 months. These are the key components of the TyG-WHtR measurement that was found to be the strongest predictor of heart disease risk in this study.
  • Set a goal to increase physical activity to at least 150 minutes per week, as the study found that exercise significantly reduced the connection between insulin resistance and heart disease risk. Use the app to log workouts and set reminders for daily movement.
  • Create a quarterly health check-in where you review your waist circumference, exercise frequency, and any available blood test results. Track trends over 6-12 months to see if your insulin resistance markers are improving. Share this data with your doctor during annual check-ups to assess your heart disease risk trajectory.

This research shows a connection between insulin resistance and heart disease risk but does not prove that insulin resistance causes heart disease. These findings are from a study of American adults and may not apply to other populations. The measurements discussed (METS-IR, TyG, HOMA-IR, TyG-WHtR) are research tools and should not be used for self-diagnosis. If you’re concerned about your heart disease risk or insulin resistance, consult with your healthcare provider who can order appropriate tests, interpret results in the context of your individual health, and recommend personalized treatment or prevention strategies. This information is for educational purposes and should not replace professional medical advice.