Yes. Smoking may increase the chance of developing prediabetes by making it harder for the body to control blood sugar. The strongest evidence links smoking with a higher risk of type 2 diabetes, while the exact added risk of prediabetes is less clearly measured. Smoking is only one factor; family history, age, weight, and activity also matter. A blood test can identify prediabetes.
What Is the Link Between Smoking and Prediabetes?
Prediabetes occurs when blood sugar levels are higher than normal but not high enough to meet the criteria for type 2 diabetes. It often develops when the body's cells stop responding properly to insulin, the hormone that helps move sugar from the blood into cells for energy. The pancreas tries to compensate by producing more insulin, but blood sugar may eventually rise. The Centers for Disease Control and Prevention (CDC) explains how this process contributes to prediabetes and the later development of type 2 diabetes.
Smoking can interfere with normal blood sugar regulation. According to the CDC's guidance on diabetes and smoking, nicotine can raise blood sugar, while chemicals in tobacco products can damage the body and cause inflammation. These effects can make it harder for the body to regulate glucose, which is why smoking is an important risk factor to address when considering long-term metabolic health.
How Much Does Smoking Increase Diabetes Risk?
The evidence linking smoking to type 2 diabetes is stronger and more clearly quantified than the evidence measuring its specific effect on prediabetes. The CDC reports that people who smoke have a 30% to 40% higher risk of developing type 2 diabetes than people who do not smoke. It also notes that the risk increases with heavier smoking. This percentage refers to type 2 diabetes, not prediabetes, and should not be interpreted as an estimate of an individual's personal risk.
The World Health Organization (WHO) includes avoiding tobacco use among the steps that can help prevent or delay type 2 diabetes. Taken together, this guidance supports quitting smoking as part of reducing diabetes-related risks. However, smoking does not mean someone will definitely develop prediabetes, and not smoking does not guarantee that blood sugar will remain normal.
Why Does Smoking Matter Even Without Excess Weight?
Body weight is one factor in diabetes risk, but it is not the only one. Smoking is associated with a higher risk of type 2 diabetes, and the CDC notes that people who smoke may have a greater risk of abdominal fat, even when they do not have overweight. This means a person should not assume their blood sugar risk is low simply because their weight falls within a healthy range.
Other factors can also contribute to prediabetes. These include:
- Being 45 years or older.
- Having a parent, brother, or sister with type 2 diabetes.
- Getting little regular physical activity.
- Having overweight or obesity.
- Having a history of gestational diabetes or polycystic ovary syndrome (PCOS).
These factors can overlap. For example, someone may smoke, have a family history of diabetes, and be physically inactive. Looking at the overall risk profile is more useful than considering any one factor in isolation. The CDC's diabetes risk-factor guidance provides further information about factors associated with prediabetes and type 2 diabetes.
Can You Have Prediabetes Without Knowing It?
Yes. Prediabetes often causes no obvious symptoms, so someone can have elevated blood sugar without feeling unwell. Feeling healthy does not necessarily mean blood sugar is within the normal range. Because symptoms are not a reliable way to identify prediabetes, blood testing is the appropriate way to check.
The CDC's diabetes-testing guidance describes blood tests used to identify prediabetes and diabetes. Two commonly used tests are the fasting blood sugar test and the A1C test. A healthcare professional can recommend testing based on a person's age, health history, and risk factors, including smoking and other contributors to diabetes risk.
Which blood tests can identify prediabetes?
The A1C test estimates average blood sugar over approximately the previous three months. According to the CDC's A1C testing guidance, the usual A1C ranges are:
- Below 5.7%: Normal range.
- 5.7% to 6.4%: Prediabetes range.
- 6.5% or higher: Diabetes range.
A fasting blood sugar test measures glucose after an overnight fast. A result of 100–125 mg/dL falls within the usual prediabetes range. A healthcare professional may consider other findings or recommend repeat testing when interpreting a result. Smoking history alone cannot establish whether someone has prediabetes.
Can Quitting Smoking Help Reduce Your Risk?
Quitting smoking is an important step toward better long-term health. It removes ongoing exposure to tobacco smoke and nicotine and supports efforts to prevent type 2 diabetes. However, quitting cannot guarantee that prediabetes will be prevented, particularly when other risk factors are present. It is still worthwhile regardless of how long someone has smoked.
The National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK) recommends stopping smoking or using other tobacco products as part of a diabetes-prevention plan. Support from a healthcare professional, counselling, and suitable smoking-cessation treatments may help make quitting more manageable.
What else can help lower diabetes risk?
Alongside quitting smoking, practical changes can help address other risk factors. Regular physical activity, balanced meals, and gradual weight loss when appropriate may reduce the chance of developing type 2 diabetes. For people who have prediabetes, structured lifestyle-change programmes can provide support with building lasting habits.
These steps work best when matched to a person's circumstances. Someone who smokes and has other diabetes risk factors can ask a healthcare professional about blood sugar testing, a suitable plan to quit smoking, and ways to improve physical activity and eating habits. Identifying risk early gives people an opportunity to make changes that support their health.
When Should You Speak With a Healthcare Professional?
Consider asking about blood sugar testing if you smoke and also have other risk factors, such as a family history of type 2 diabetes, overweight, or limited physical activity. Testing may also be appropriate based on age or a history of gestational diabetes. A clinician can review these factors and recommend whether testing is needed and when it should be repeated.
If a test shows prediabetes, it does not mean type 2 diabetes is inevitable. Lifestyle changes and appropriate follow-up can help reduce the chance of progression. Quitting smoking is one meaningful step, and it can be combined with other changes based on individual needs.