As a whole, people living with type 1 diabetes experience heart disease far more than even those suffering from type 2 diabetes. This is true despite the fact that type 2 is a condition associated with all the major risk factors of heart disease including obesity, high blood lipids, and high blood pressure.

Stranger still, women living with type 1 experience heart disease at rates greater than men with type 1 and both men and women with type 2.

So why is it that type 1 women’s hearts seem so vulnerable to the damage caused by this specific condition?

To understand this surprising phenomenon, we first need to take a step back and look at how T1D, in general, affects cardiovascular health.

Why T1D People Face Greater Risk of Heart Disease

People living with T1D come in all shapes, sizes, and ages. Some are athletes, some are overweight. Some have been treating the condition with great success for decades, while others struggle.

Despite these differences, every person with T1 diabetes shares an increased risk of cardiovascular complications.

While many aspects of lifestyle and general health play into an individual’s risk for heart disease, there are certain risks associated with T1D that you just can’t escape. No matter your BMI, A1C, or HDL.

High Blood Sugars

One of the most widely accepted reasons for diabetes increasing cardiovascular disease (CVD) risk, is the damaging effects of high blood sugar. 

High glucose levels cause stronger contraction of blood vessels. In turn, this forces the heart to work harder to pump blood to the organs and extremities. Additionally, frequent high blood sugars can lead to hardening of the blood vessels and damage to the heart itself.

Widely Varying Blood Sugars

If high blood sugar alone was responsible for increased CVD risk, then T1Ds with lower A1Cs would show a comparable decreased risk in this area. But we don’t see that kind of consistent linear association in the data. One explanation may be related to oxidative damage to blood vessels caused by wide swings in blood sugar.

When sugars go high quickly after a meal and then fall low a few hours later, it causes oxidative stress to your cardiovascular system. But, because A1C is only an average of blood sugar levels, it tells us nothing about how often we experience these swings. It is possible that people with lower A1Cs who still suffer from CVD have experienced this type of oxidative stress.

Autoimmune Response

While blood sugars do tend to go higher and swing more dramatically in type 1s versus type 2s, these differences alone aren’t enough to explain the huge variation in risk between the two conditions. But one major difference between these two common types of diabetes might.

T1D is an autoimmune disease in which the immune system attacks insulin-producing cells in the pancreas. But this type of damage may not be limited to just that one organ. A study published in 2018 found a similar autoimmune attack of the heart muscle in some T1Ds. While this process appears to be made worse by poor control, there seem to be a number of factors that influence who is most affected.

Complication Feedback

In addition to the heart, T1D has a number of associated complications including nerve damage, eye problems, and kidney disease. Many of these complications have a direct or indirect effect on a person’s heart health.

For instance, kidney failure can cause high blood pressure. While a person suffering from neuropathy may find it too painful to exercise regularly. Even if a person is not physically limited, any complication can affect mental health, leading to a more sedentary lifestyle, poor diet choices, and worsening blood sugar control. Even something as simple as avoiding carb-heavy plant foods in favor of low-carb meats and cheeses can have a negative impact on heart health.

Why Women Living with Diabetes Have the Greatest CVD Risk

Everything about type 1 diabetes seems to have a negative effect on a person’s heart. But, so far, all the issues we’ve looked at would appear to affect males and females equally. So where does the increased risk for women come from?

First, we have to consider that not all the reasons listed above are, in fact, gender-neutral. 

Multiple studies of the healthcare industry have shown that women routinely receive lower quality and less acute care than men. For a diabetic, less quality and less frequent care often mean higher and less consistent blood sugars. Both things we know lead to a greater risk of heart disease.

It’s also worth considering that women living with T1D might be more prone to autoimmune attacks on the heart muscle. Unfortunately, the study that demonstrated the existence of autoimmune heart damage did not give their results by gender.

Non-diabetic men suffer from heart disease more often than non-diabetic women. But the opposite is true of diabetics. Some theorize that this might have something to do with abdominal fat. Women, in general, carry more weight around their midsection than men. It’s possible that this specific type of fat has a cumulative effect when combined with diabetes.

Despite the fact that more non-diabetic men than women have CVD, some studies suggest that women actually have less control of CVD risk factors like blood pressure and smoking status. Women even appear to more commonly have high cholesterol than men. 

Usually, all of these factors are negated by the heart-protecting qualities of estrogen. But in diabetic women, that protection appears to be negated.

Protecting the T1 Woman’s Heart

While we may only be able to speculate on the exact cause of T1D women’s increased risk of CVD, that doesn’t mean we are powerless to fight it.

Over the next few articles in this series, I will be taking an in-depth look at how you, as a woman living with diabetes, can reduce your risk of developing heart disease. For those out there who already have cardiovascular complications, we will dive into what it takes to manage the condition and your best shot at improving your heart health.