Does it make sense to study your genes to prevent type 2 diabetes or a heart attack?

More and more people are considering a genetic health test to find out whether they have a higher risk of type 2 diabetes or cardiovascular disease and decide what to do in time. The key question is not just “what is my risk?”, but: does knowing it really change anything in my prevention plan? Do genes matter more than lifestyle, or is it the other way round?

“A high genetic risk is not a sentence: it signals that you have more room to act through your lifestyle to neutralise much of that risk.”

1. What genetic risk tests measure in type 2 diabetes and heart disease

Health tests that assess the risk of type 2 diabetes or coronary heart disease are usually based on polygenic risk scores.

• There is no single “diabetes gene” or “heart attack gene”; instead, there are dozens or hundreds of variants, each with a small effect.
• Taken together, they make it possible to classify people into low, medium or high genetic risk groups relative to the general population.

Recent studies in large cohorts show that these scores are robustly associated with the likelihood of developing type 2 diabetes or coronary heart disease over the years. This information is genuinely useful when integrated with factors such as glucose, lipids, blood pressure, BMI and smoking.

Type 2 diabetes: genes, diet and lifestyle

Type 2 diabetes is a clear example of a complex disease: it depends on both genetics and habits.

• A study across several cohorts analysed how genetic risk (PRS) and diet quality combine and found that both, separately, increase diabetes risk; however, within each genetic category, following a high-quality diet was associated with an approximately 30% lower risk of developing the disease.​
• Another study that developed a type 2 diabetes-specific PRS in an Asian cohort showed that this score can identify individuals who benefit particularly from intensive lifestyle interventions.​

The recurring message has two parts:

1. Genetics helps identify who is “on a tightrope”.
2. Improvements in diet and other habits reduce risk across all levels of genetic risk.

3. Cardiovascular disease: high genetic risk, greater benefit from healthy habits

In coronary heart disease, the evidence is similar and even stronger.

• In studies that combine PRS for heart disease with an assessment of habits (diet, exercise, smoking and weight), people with high genetic risk and an unfavourable lifestyle have the highest risk of early cardiovascular events.
• However, people with high genetic risk who follow an ideal lifestyle (not smoking, a healthy weight, physical activity and a heart-healthy diet) substantially reduce that excess risk and even show additional decades of life free from coronary heart disease compared with people with high genetic risk and poor habits.

A recent review summarises that a substantial part of the excess risk associated with high genetic scores can be neutralised in individuals who meet criteria for ideal cardiovascular health. Once again, genetics is not a fixed destiny, but an indication of how much room we have to act through lifestyle.

4. What knowing you have “high genetic risk” can offer

Knowing that you are in a high genetic risk group for type 2 diabetes or heart attack can offer several concrete benefits when handled appropriately:

• Prioritising interventions: the same recommendations (improving diet, moving more and stopping smoking) apply to everyone, but studies suggest that people with greater genetic risk may obtain a greater absolute benefit from adopting them.
• Motivation and adherence: some studies in precision medicine and “healthy living medicine” suggest that, when explained well, risk information can improve motivation to maintain lifestyle changes over time.​
• More targeted screening and follow-up: it may justify starting earlier or monitoring certain markers (glucose, lipids and blood pressure) more closely in people who are still “well” according to standard ranges.
• Selecting preventive strategies: in subgroups at very high coronary risk, there are data showing that certain preventive pharmacological interventions provide particularly relevant benefits.

It is important to emphasise that these uses make sense within a clinical framework and with professional interpretation; outside that context, a “high risk” result in a report can cause concern without translating into a useful plan.

5. What genetics does NOT do (and marketing sometimes promises)

Why is it important not to undertake the test on your own, and to have it interpreted by a professional?

• A high PRS does not diagnose type 2 diabetes or coronary heart disease; it indicates a higher probability, not certainty.
• A low PRS does not make you immune: a very poor diet, physical inactivity or smoking can still greatly increase your risk, regardless of your genetics.
• At present, most direct-to-consumer tests are not integrated into formal clinical guidelines, and the quality of panels and interpretation varies. It is important to choose a test such as Health Code’s, interpreted by professionals.

The general recommendation is therefore to use genetics as an additional layer of information about your risk, and to take action. It should not be an excuse to relax or become excessively alarmed.

6. When does it make sense to have a genetic risk test for these diseases?

Taking the evidence and cautions into account, it may make more sense to consider a genetic risk test for type 2 diabetes or heart disease when:

• There is a clear family history of early cardiovascular disease or type 2 diabetes in several first-degree relatives.
• You already have some conventional risk factors (early rises in glucose, dyslipidaemia or excess weight) and want to refine the intensity and priority of interventions.
• You want to take control of your health and be proactive in helping to prevent disease, integrating these results into a clearly defined plan developed by a professional.

In that context, a test can help you see more clearly where to focus your efforts and what risk horizon you are dealing with.

7. How to turn genetic information into practical decisions

In practice, what matters is what changes in your day-to-day life. In very simplified terms:

• If your genetic risk is high
  It makes sense to:
  • Take a more intensive approach to the pillars of lifestyle (diet, exercise, weight and smoking).
  • Start screening and regular check-ups earlier.
  • Discuss with your professional whether certain preventive treatments make more sense in your case.
• If your genetic risk is low or medium
  Healthy lifestyle recommendations remain just as important; studies indicate that a good diet and an active lifestyle reduce the risk of diabetes and cardiovascular disease across all levels of genetic risk.

In both cases, genetics helps adjust the degree of urgency and intensity and personalise treatment, rather than change the fundamentals of prevention.

8. In summary: what looking at your genes can and cannot do here

Current science points to a balanced model:

• Your genes for type 2 diabetes and heart attack matter and can be measured using increasingly refined polygenic scores.
• Your lifestyle does not just matter; it can buffer much of the risk, even in people with a high genetic predisposition.
• Genetic health tests are a very useful tool when used to stratify risk, motivate changes and personalise prevention, always as part of a comprehensive clinical assessment.

If you decide to study your genes, the aim should not be to label you, but to help you make more informed preventive decisions before disease develops.