Life with type 1 diabetes requires a near-constant focus on day-to-day blood sugar management.
This may make it more difficult to concentrate on long-term health, which may be partly why there’s often little discussion about potential risk of cardiovascular disease.
But that discussion about heart health should happen more often, as it’s a leading cause of death among people with type 1 diabetes.
In fact, research has confirmed that people with T1D have a much greater risk for experiencing serious cardiovascular complications (heart attack, stroke, coronary artery disease) than the general population.
The good news is that early treatment to manage the risk factors for cardiovascular disease can significantly reduce the chances of serious complications.
If you’re an adult of any age living with T1D, it’s important to begin a conversation with your healthcare provider about your heart health prospects.
To help with that conversation, we’ve compiled answers to some key questions about the connection between type 1 diabetes and cardiovascular disease.
Unfortunately, yes. People with T1D are more likely to experience cardiovascular disease, and to receive a diagnosis of it at an earlier age, than the general population.
Research has shown that the annual rate of major coronary artery disease in young adults (ages 28 to 38) with type 1 diabetes was 0.98 percent, while the same rate for a similar-aged population without diabetes was just 0.1 percent.
“Cardiovascular disease continues to be the leading cause of morbidity and mortality in individuals with type 1 diabetes,” says Dr. Marina Basina of the Stanford Health Care Endocrinology Clinic.
“Remarkable improvements in management and survival have been observed during the past century, allowing people to live longer and healthier lives, but life expectancy still remains 8 to 13 years shorter comparing to the individuals without diabetes,” Basina says.
Basina says the exact cause of how type 1 diabetes affects the cardiovascular system isn’t known. High blood pressure, high cholesterol, and diabetic kidney disease can all play a role, if present.
Hyperglycemia (high blood sugar) itself is considered to be a leading reason for elevated risk, as it can damage blood vessels and nerves essential for circulation and heart health.
This can lead to neuropathy (damage to the nervous system), which can lead to abnormalities in the vascular system as well.
It helps to remember that your cardiovascular system isn’t that different than plumbing pipes, says Gary Scheiner, a well-known Diabetes Care and Education Specialist (DCES), author, and clinical director of Integrated Diabetes Services in Pennsylvania.
“The way I explain it to patients is this: Sugar is a very sticky substance. Imagine dumping maple syrup down your kitchen sink every time you do the dishes. Eventually, that syrup is going to combine with all the other leftover food that we dump out to form blockages in the pipes,” Scheiner tells DiabetesMine.
While hyperglycemia is often the focus of studies on heart health and type 1 diabetes, researchers also know that hypoglycemia can stress the heart and increase the risk of cardiovascular disease as well. That’s because hypoglycemia can disrupt electrical signals that are vital for heart function.
However, researchers haven’t yet been able to isolate exactly how large a role hypoglycemia may play, independent of other factors, in causing cardiovascular events.
It’s a stubborn problem, in that research even demonstrates that people with T1D who take the traditional steps to lower cardiovascular risk still have a higher risk of death from cardiovascular issues than the general population.
In contrast, people with type 2 diabetes who underwent similar interventions had a more substantially reduced risk for death from cardiovascular issues, one that aligned closely with the risk faced by the general population.
But Stanford’s Basina points out that the research may be confounded because the study groups and control groups for T1D versus T2D heart health trials were very different.
“The bottom line is that we cannot directly compare if the risk is more or less. We can just say that it is different,” she says.
Research into increased risk of death from cardiovascular issues seems to suggest that this risk spikes after the development of nephropathy, or damage to the parts of the kidneys that clean the body’s blood.
People with type 1 diabetes have an increased risk for having one or more other autoimmune conditions. This can include autoimmune issues that can affect heart health.
In some people with type 1 diabetes, blood glucose swings that can cause repeated injury to the heart can, in turn, cause the body’s own immune system to attack the heart, much as it attacks the pancreas. This process is called
A study conducted by researchers with the Joslin Diabetes Center in Boston and other institutions found that blood sugar management that significantly fails to meet glycemic targets can lead to increased risk of cardiac autoimmunity in people with type 1 diabetes.
Their research also found that cardiac autoimmunity was associated with long-term, increased risk of cardiovascular disease.
Research is just beginning to provide some possible answers to this question, but there appears to be evidence that the age of diagnosis is tied to risk of heart complications.
A large study in Sweden that tracked 27,000 people with type 1 diabetes found that those who were diagnosed earlier in life had a greater number of cardiovascular complications than those who got their diagnosis later in life.
For example, those who were diagnosed before the age of 10 had a 30 times greater risk for serious cardiovascular outcomes than those diagnosed after that age. (Note that women diagnosed before the age of 10 had a significantly higher risk than men diagnosed before the age of 10.)
Dr. Araz Rawshani from the University of Gothenburg in Sweden, who co-led the study, said in a statement that such findings “warrant consideration of earlier treatment with cardioprotective drugs” for those who were diagnosed with type 1 diabetes in childhood.
Research shows that people with type 1 diabetes do generally have more HDL (good) cholesterol, which can help protect heart health in the general population.
But alas, not all HDL is created equal. People with T1D are more likely to have the type of HDL that can convert to a molecule that promotes inflammation, and chronic inflammation is associated with cardiovascular disease.
A U.K. study of teens with type 1 diabetes, for example, found that many participants had elevated HDL, and that those levels could negatively affect the membrane that controls how the heart muscles squeeze and relax.
Basina adds that efforts to create medication that could raise HDL failed to show a decrease in the likelihood of heart disease. Meanwhile, she says there’s actually more evidence on the flip side, showing that low HDL is a risk factor of heart disease.
If you’re an adult living with T1D, your doctor or healthcare team should be regularly monitoring your heart health.
Blood pressure should be checked at each doctor visit. Hypertension is diagnosed and treatment started if blood pressure is above 140/90.
The American Diabetes Association also recommends a cholesterol (lipid) panel test every 5 years under the age of 40, and “more frequently” thereafter, particularly in people who’ve had T1D for a long time. (But no specific frequency is defined for this blood test taken in a lab setting.)
The type and frequency of further screening tests ordered will vary from patient to patient, says Scheiner.
“Screening should be individualized based on each person’s risk factors. Those with additional risk factors (smoking, obesity, hypertension, hypercholesterolemia, physical inactivity, family history of heart disease) will need more aggressive screening measures,” he says.
Here are some of the tests people with at-risk hearts might be asked to take:
- Doppler ultrasound. This noninvasive test estimates blood flow through the body’s blood vessels and checks for possible injuries. The test bounces high-frequency sound waves off circulating blood cells. It can be done as an ultrasound of heart vessels and carotid arteries, the large vessels in the neck that supply the brain.
- Electrocardiogram (EKG). An EKG is a painless test that measures your heart’s electrical activity. A technician attaches electrodes to your chest, arms, and legs with a gel, and then records the heart’s electrical activity when you’re at rest.
- Exercise stress test. In this test, an electrocardiogram records your heart’s electrical activity during peak physical exercise, usually conducted on a treadmill.
- Coronary angiography. This surgical test finds possible blockages in the arteries. A contrast dye is injected into your veins, and then an X-ray monitors your blood flow.
The tests above are most often prescribed (and covered by insurance) for people who already exhibit some symptoms of heart trouble. However, new technologies on the horizon are set to change the game in accurate prescreening.
For example, the noninvasive early screening tests being developed by startups HeartFlow and Cardisio will potentially save hundreds of people from having sudden unexpected heart attacks, which often strike with no warning signs.
Here are some possible symptoms:
- chest pain
- shortness of breath
- rapid heartbeat or palpitations
Avoiding foods high in saturated fat is strongly encouraged, Basina notes. The following can also help:
- reducing weight if overweight
- increasing consumption of vegetables and low fat dairy products
- avoiding excessive alcohol consumption
- increasing physical activity
There are a few type 2 diabetes medications that are designed both to help with blood sugar management and protect the heart.
While those drugs aren’t currently approved by the Food and Drug Administration for use in treatment of type 1 diabetes, a significant number of people with T1D use them “off-label” under the care of a healthcare provider.
Here are the various type 2 diabetes medications that may also be prescribed, in some cases, to help with heart health:
- glucagon-like peptide-1 (GLP-1) receptor agonists, including:
- albiglutide (Tanzeum)
- dulaglutide (Trulicit)
- exenatide (Byetta)
- extended-release exenatide (Bydureon)
- liraglutide (Victoza)
- lixisenatide (Adlyxin)
- sodium-glucose transport protein 2 inhibitors (SGLT2s), including:
- canagliflozin (Invokana)
- dapagliflozin (Farxiga)
- empagliflozin (Jardiance)
- ertugliflozin (Steglatro)
Naturally, any new medication can come with risks. For example, GLP-1 receptor agonists can cause increased risk of diabetic ketoacidosis (DKA), and SGLT2 drugs may increase the risk of a serious but rare infection around the genitals.
If you’re using a type 2 diabetes medication off-label, be sure to monitor for unusual symptoms and discuss the risks with your doctor.
Overall healthy lifestyle habits are your best bet, according to Basina. That includes:
- eating healthy (Mediterranean diet is the most widely studied and recommended) and avoiding saturated fat
- keeping a moderate weight (avoiding weight gain, or losing weight if overweight)
- getting at least 150 minutes per week of moderate-intensity exercise
- getting regular good sleep
- managing your blood sugar well with avoidance of severe hypoglycemia
- discussing specific recommendations pertinent to you with your healthcare team
As the research on cardiovascular disease and type 1 diabetes continues to evolve, so do the specific guidelines for prevention and treatment.
Not surprisingly, there’s research suggesting that tight blood glucose management may reduce the risk of heart disease in people with T1D.
However, what the goals of that management might look like is evolving, especially as we more fully understand the effects of hypoglycemia on the body.
In the past, goals often focused on lowering A1C, as higher A1C has been associated with increased risk of cardiovascular complications.
However, another indicator of glycemic management is gaining importance. In 2019, the American Diabetes Association unveiled new recommendations that suggest that healthcare providers should consider Time-in-Range (TIR) as a key indicator of blood glucose management.
This is defined as time spent with blood glucose levels between 70 mg/dL and 180 mg/dL. Evidence suggests a strong correlation between TIR and risk of vascular issues among people with type 1 diabetes.
Prevention and treatment of heart risk factors are generally the same for people with T1D as for everyone else: medications, dietary changes, and regular exercise or other lifestyle interventions.
The first step, as always, is to have regular conversations with your healthcare providers about your risks, as well as about any potential symptoms you might feel.
Don’t hold back on this topic. Don’t wait until you think you are “old enough” to address it. The time to start thinking about your heart health with type 1 diabetes is now.