The Clock Starts Early: Heart Disease Risk Builds Decades Before a Type 2 Diabetes Diagnosis
- t2diabetesnetwork
- 18 hours ago
- 6 min read
Key Highlights
✅ Diabetes raises heart disease risk years before diagnosis
✅ Women face higher risk of silent heart attacks
✅ Early signs often go unnoticed -- screening matters
✅ Lifestyle changes can protect heart and delay T2D
✅ Prevention must start decades before diagnosis
Did you know that most people with diabetes (65-80%) die from heart disease? It's a sobering fact, highlighting a crucial link. If you have diabetes, especially if you're a woman, your risk of heart problems like atherosclerosis is higher and can start earlier. What's more, many heart attacks in people with diabetes can happen silently, without typical symptoms.
In 2008/2009, close to 2.4 million Canadians, about 7% of the population, were living with diagnosed diabetes. Similarly, heart/cardiovascular disease (CVD) remains the second leading cause of death amongst Canadians, only surpassed by cancer, with a significant portion of the burden driven by preventable risk factors such as type 2 diabetes (T2D), obesity, hypertension, and smoking.
Concerningly, people living with T2D are more than three times more likely to die of heart disease compared to those without diabetes. This link is well-established, as chronic hyperglycemia contributes to endothelial dysfunction, atherosclerosis, and inflammation, core mechanisms underlying CVD.
But that's not the only system affected. Diabetes contributes to four out of ten heart attacks, three out of ten strokes, half of all kidney failure cases requiring dialysis, is the leading cause of blindness, and is responsible for seven out of ten non-traumatic leg and foot amputations.
As the prevalence of T2D continues to rise in Canada, especially among younger adults and racialized populations, a proactive, population-level approach to cardiovascular risk assessment and lifestyle intervention is increasingly critical.
Focus on T2D Heart Connection
Let's hone in on the impact on the cardiovascular system, or rather, when this starts. It's a case of the chicken or the egg: is cardiovascular disease present before the diabetes diagnosis or does it result from the diagnosis?
A groundbreaking nationwide registry study from Denmark, recently published in the Journal of the American College of Cardiology in December last year, has revealed that individuals who eventually develop T2D begin to experience significantly higher rates of CVD up to 30 years before their diabetes diagnosis. This large study, which included over 127,000 individuals with T2D and more than 381,000 matched population controls, found a consistent and substantial increase in cardiovascular events, defined as myocardial infarction or ischemic stroke, long before diabetes is ever diagnosed.
People who eventually develop type 2 diabetes already have a much higher chance of having a heart attack or stroke many years before they’re diagnosed. In fact, even 25 to 30 years before being diagnosed, their risk is already more than twice as high as people who don’t get diabetes. As they get closer to diagnosis, their risk keeps going up. In the five years just before they’re diagnosed, their chance of having a heart-related event is nearly three times higher. And even after they’re diagnosed, their risk of heart problems stays high for at least the next five years.
This study challenges the conventional clinical timeline in which cardiovascular risk management begins only once diabetes is diagnosed or prediabetes is identified. Instead, it underscores the reality that metabolic and vascular damage begins decades earlier, likely driven by underlying insulin resistance, inflammation, and other shared risk factors.
Supporting Studies and Evidence
We know that people with diabetes are at much higher risk of CVD, and this risk begins years before the diabetes is officially diagnosed. Scientists now also know this connection is not just due to high blood pressure or clogged arteries, there are direct effects of diabetes on the heart muscle itself.
One of these effects is known as diabetic cardiomyopathy It refers to changes in how the heart looks and works in people with diabetes, even when there’s no history of coronary artery disease or high blood pressure. These changes often go unnoticed at first (asymptomatic), but over time they can lead to heart failure. The underlying mechanisms include oxidative stress, inflammation, damage to the cells lining blood vessels (endothelial dysfunction), and problems with how calcium is handled in heart cells. Understanding these processes can help us find ways to catch heart damage early and treat it effectively.
A large study from the ASIAN-HF Registry examined the impact of type 2 diabetes (T2D) on individuals with heart failure, comparing those with reduced ejection fraction (HFrEF) and preserved ejection fraction (HFpEF). T2D was present in 40.2% of HFrEF patients and 45.0% of HFpEF patients. Additionally, diabetes was linked to a 27% higher risk of heart failure rehospitalization and a 22% increased risk of death or hospitalization within one year, regardless of heart failure type. These findings highlight the significant and consistent burden of T2D on heart structure, function, and clinical outcomes in patients with heart failure.
Implications for Current Heart Guidelines and Screening
Current national guidelines also reflect growing awareness of the need for early intervention, although they may not yet go far enough. Screening: What Works?
While screening for heart disease sounds good, studies haven't yet proven that routine screening in asymptomatic individuals with diabetes significantly improves survival. However, if your doctor suspects heart disease, various tests can help.
Stress tests, like exercise ECGs, are valuable for high-risk individuals to understand their prognosis. But remember, a significant number of people with diabetes who have heart disease won't experience chest pain. Other clues, like shortness of breath or an abnormal resting ECG, are important to watch for. An abnormal resting ECG, particularly with certain changes, is a strong indicator of silent heart issues, especially for women.
Newer imaging, like Coronary CTA (CT angiography), can show heart artery disease early. If your Coronary CTA is normal, it's generally good news, suggesting a low risk of heart events for at least five years. Coronary Artery Calcium (CAC) scoring is another strong predictor of future heart problems.
While various tests like stress tests, Coronary CTA, and CAC scoring can help assess risk, current research doesn't definitively support routine screening for heart disease in asymptomatic (silent) individuals with diabetes to improve survival outcomes. Peripheral artery disease is also common in diabetes, and although checking pulses is a simple screening method, its diagnostic accuracy is limited despite its prognostic value. Type 1 diabetes also carries a substantially increased, and often earlier, risk of heart disease, with some studies suggesting women with type 1 diabetes may face an even higher (two-fold) mortality risk from cardiovascular disease than men.
Given these complexities, a personalized approach focusing on overall risk factor management rather than widespread asymptomatic screening is generally favored. Understanding these risks is the first step toward better heart health with diabetes.
A Call for Earlier Action
Healthcare providers should no longer view the diagnosis of T2D as the starting point for cardiovascular prevention, it’s already late in the game. Instead, risk assessments for CVD should begin much earlier in life, especially in those with family histories of diabetes, metabolic syndrome, or obesity. Patients, too, must be empowered to understand and track their cardiovascular risk factors from a younger age, including monitoring their blood pressure, cholesterol, waist circumference, and physical activity.
Health systems and policymakers also have a role to play. Investment in population-level prevention strategies, including early screening and health education in schools and workplaces, could drastically reduce the long-term burden of both T2D and CVD. These strategies are particularly crucial in younger adults, whose risk may not yet be reflected in traditional screening models but whose future health could be shaped by interventions made now.
What Can You Do Now?
Preventing cardiac disease in T2D requires a multi-faceted strategy - we've gathered all the resources for you on our T2D Network website to help you though.
A cornerstone of prevention involves lifestyle modifications, with extensive guidance on healthy eating emphasizing fruits, vegetables, whole grains, and healthy fats, alongside limiting processed foods and red meats, which is linked to a reduced risk of obesity, heart disease, and certain cancers.
Regular physical activity is also crucial; recommendations from Diabetes Canada suggest at least 150 minutes of moderate-intensity aerobic exercise and two resistance exercise sessions per week, with evidence indicating that higher activity levels are associated with significantly lower morbidity and mortality in people with diabetes.
Beyond lifestyle, aggressive management of traditional cardiovascular risk factors is essential. Blood pressure control is paramount, with guidelines suggesting a target of less than 130/80 mmHg for most people with diabetes and at risk for cardiovascular disease, acknowledging the continuous and graded association between BP and cardiovascular risk. Similarly, lipid management through statin therapy is recommended for people with diabetes, with high-intensity statins for those with established cardiovascular disease, to reduce LDL cholesterol and thereby lower cardiovascular risk.
Assess your cardiac risk here with the Canadian Cardiovascular Society recommended CardioRisk calculator.
Starting the Clock Early
Ultimately, we need to turn a spotlight on the hidden burden of cardiovascular disease in people on the path to diabetes. Recognize that prevention efforts must start not at diagnosis, but decades earlier. If we want to stop the clock on cardiometabolic disease, we have to start listening to its ticking much sooner.
Join us to stay tuned for more evidence based T2D discussions.
Listen to this blog on your phone
Comments