Smoking and Diabetes: New Research Shows How Tobacco Raises Risk Across All Types of Type 2 Diabetes

When most people think about smoking, they think of lung cancer, heart disease, or emphysema. But did you know that smoking is also a major risk factor for type 2 diabetes?

In fact, according to the Centers for Disease Control and Prevention (CDC), people who smoke are 30–40% more likely to develop type 2 diabetes than nonsmokers. Once a smoker develops diabetes, the disease is also much harder to control.

Now, new international research confirms what U.S. experts have long suspected: smoking doesn’t just raise the general risk of diabetes — it affects all subtypes of type 2 diabetes, with the greatest impact on forms linked to insulin resistance.

Most people have heard of type 1 and type 2 diabetes. But researchers now know that type 2 diabetes can be broken into four main subtypes, each with different patterns:

• SIRD — Severe Insulin-Resistant Diabetes (body doesn’t respond well to insulin).
• SIDD — Severe Insulin-Deficient Diabetes (pancreas doesn’t produce enough insulin).
• MOD — Mild Obesity-Related Diabetes (often starts younger, linked to weight).
• MARD — Mild Age-Related Diabetes (typically develops later in life).

While all of these fall under the “type 2” umbrella, they behave a little differently and carry different complication risks. Until recently, it wasn’t clear whether risk factors like smoking influenced them all the same way.

At the European Association for the Study of Diabetes (EASD) meeting in Vienna, researchers from Sweden, Norway, and Finland analyzed data from more than 7,000 people. They discovered that:

• Both current and former smokers were at higher risk of developing all four subtypes of type 2 diabetes.
• The strongest link was with SIRD (the insulin-resistant form). Smokers had over twice the risk compared with nonsmokers.
• Heavy smoking (15 or more “pack-years”) raised risk even more — up to 2.3 times higher for insulin-resistant diabetes.
• Genetics made things worse. People with a family history or genetic predisposition to poor insulin production or insulin resistance were especially vulnerable if they smoked.

In short: smoking plus genetic risk is a dangerous combination.

U.S. health agencies have been sounding the alarm for years:

• The FDA notes that nicotine and other chemicals in tobacco can damage cells, increase inflammation, and interfere with how the body uses insulin.
• The CDC emphasizes that smokers who develop diabetes have a harder time controlling blood sugar, which leads to more complications like kidney disease, vision loss, and heart problems.
• A review published in the Journal of Diabetes Research found that quitting smoking not only reduces the risk of developing diabetes but also helps improve insulin sensitivity in people who already have the disease.

Dr. Edward Gregg, former chief of epidemiology at the CDC’s Division of Diabetes Translation, put it simply:

“Smoking is one of the most preventable risk factors we can act on. Quitting makes a meaningful difference for blood sugar control and long-term health.”

Diabetes already affects over 38 million Americans (about 1 in 9 adults), and another 98 million have prediabetes. Smoking piles on risk, especially for those who:

• Have a family history of diabetes
• Struggle with weight or abdominal fat
• Already have high blood pressure or cholesterol

For these individuals, smoking can tip the scale toward diabetes sooner and make the disease harder to manage.

If you’re 50 or older — or at higher risk due to weight, family history, or lifestyle — here’s what experts recommend:

1. Quit smoking (or don’t start). Ask your doctor about nicotine replacement, prescription medications, or support programs.
2. Get screened regularly — blood sugar, cholesterol, and blood pressure checks are simple but lifesaving.
3. Stay active — just 30 minutes of walking most days can improve insulin sensitivity.
4. Eat for balance — cut back on sugary drinks and processed foods, and increase whole grains, vegetables, and lean proteins.
5. Know your risks — if you have family history or are already showing signs of insulin resistance (like belly weight or prediabetes), talk to your doctor about a personalized prevention plan.

Smoking isn’t just a lung or heart problem — it’s a diabetes problem too. The latest research shows that tobacco increases the risk of every subtype of type 2 diabetes, especially the insulin-resistant kind that’s hardest to treat.

The good news? Quitting works. No matter your age or genetic risk, stopping smoking lowers your chances of developing diabetes and helps your body respond better to insulin.

As U.S. experts stress: it’s never too late to quit — and your future self will thank you for it.