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Experts say a heart-healthy diet is a key component to avoiding prediabetes. 10’000 Hours/Getty Images
  • Researchers say prediabetes can increase the risk of cardiovascular events such as heart attack and stroke.
  • They say that many times there are no warning signs for these heart-related incidents.
  • They recommend people maintain a heart-healthy diet and get sufficient exercise to keep blood sugar levels in normal ranges.

Prediabetes may sound harmless, but new research warns that it’s not a benign condition.

The link between type 2 diabetes and heart disease is well established. But prediabetes also increases the risk of cardiovascular disease, according to a study published in the Journal of the American College of Cardiology.

“In general, we tend to treat prediabetes as no big deal,” Dr. Adrian Michel, the study’s lead author, said in a press release. Michel, an internal medicine resident at Beaumont Hospital in Royal Oak, Michigan, will present the research May 16 at the American College of Cardiology’s 70th Annual Scientific Session.

“But we found that prediabetes itself can significantly boost someone’s chance of having a major cardiovascular event, even if they never progress to having diabetes. Instead of preventing diabetes, we need to shift focus and prevent prediabetes,” he said.

The retrospective study involved more than 25,000 people between 18 and 104 years old. All were treated within the Beaumont Health System in Michigan between 2006 and 2020.

The researchers separated participants into a prediabetes group and a control group based on results of at least two A1C level tests taken 5 years apart. The A1C test finds a person’s average blood glucose level over the previous 3 months.

Among study participants, 18 percent of those with prediabetes had a serious cardiovascular event, compared with 11 percent of those in the control group. Median follow-up was 5 years.

Bringing blood sugar back to the normal range helped, but risk was still elevated. About 10 percent experienced a cardiovascular event, compared with 6 percent of those who didn’t have prediabetes.

Study authors acknowledge that more research is needed.

Dr. Megan Kamath is an advanced heart failure and transplant cardiologist and assistant clinical professor of medicine at the David Geffen School of Medicine at the University of California, Los Angeles.

She told Healthline that this is an important reminder for people and doctors to focus on prevention of cardiovascular disease through modification of risk factors.

Prediabetes is when the blood sugar level is above normal yet not high enough for a diagnosis of type 2 diabetes.

About 1 in 3 adults in the United States have prediabetes, according to the Centers for Disease Control and Prevention (CDC). That’s 88 million people, and most don’t know it because there are few symptoms.

If left unchecked, prediabetes can progress to type 2 diabetes.

According to the American Diabetes Association, people with diabetes are twice as likely to have heart disease or a stroke than those who don’t have diabetes. And cardiovascular disease is the top cause of death for people with diabetes.

“It’s important to remember that one blood sugar reading alone does not determine whether you have prediabetes,” Kamath said.

“The CDC recommends that patients should get screened with a hemoglobin A1C at least every 1 to 2 years, sometimes more often if your medical provider recommends,” she continued.

To help prevent prediabetes, Kamath recommends a heart-healthy diet focusing on whole foods and limiting carbohydrates.

“Aim to maintain a healthy weight, increase physical activity, manage stress, avoid smoking, alcohol and other drugs, and treat underlying medical conditions,” she said.

Those same lifestyle changes are key to get prediabetes under control.

Dr. Victoria Shin is an interventional cardiologist with Torrance Memorial Medical Center in California.

She told Healthline that cardiovascular events such as heart attacks and strokes often strike suddenly and without warning.

Shin adds that exertional chest pain or exertional shortness of breath could hint at heart trouble.

“If these symptoms occur, seek medical attention,” she said.

“The key is to control the factors that increase your risk for them: diabetes, hypertension, cholesterol, obesity, tobacco abuse. They call these risk factors ‘silent killers’ because you may ‘feel fine’ even though they are not controlled,” said Shin.

“When it comes to cardiovascular disease, approximately 80 percent can be prevented,” said Shin. “Yet it remains the No. 1 cause of death because risk factors such as prediabetes, diabetes, hypertension, cholesterol, and obesity are not well controlled.”

It can be difficult for people who “feel fine” to adjust their lifestyle and daily habits.

“But it’s the daily habits that contribute to risk — what we eat, the exercise we do. These will help to prevent a lot of these risk factors,” Shin said.

Once problems develop, Shin urges people to comply with their treatment plan, including taking medications, following a heart-healthy diet, and exercising.

“It’s often challenging as a physician to convince patients to adjust their lifestyle and take medications for issues that don’t necessarily make them feel bad. Though in reality, prevention is so much better than trying to fix a problem once a patient has an event,” Shin said.