New research reveals that smoking significantly raises the risk of developing all four subtypes of type 2 diabetes — especially in people who are already genetically at risk.
The study, presented at the European Association for the Study of Diabetes in Vienna, shows that even light smoking can increase your chances of getting diabetes, while heavy smoking raises the risk even more.
Study Overview: Smoking and Diabetes Connection
Researchers from the Karolinska Institute in Stockholm analyzed health data from over 7,000 people — 3,325 with type 2 diabetes and 3,897 without — from studies in Norway and Sweden.
They found a clear link between smoking and a higher risk of developing different types of diabetes, regardless of the cause — whether it’s due to insulin resistance, lack of insulin, obesity, or age.
Lead researcher Emmy Keysendal said, “It is clear that smoking increases the risk of type 2 diabetes whatever the subtype.”
How Smoking Affects Each Diabetes Subtype
The study broke down type 2 diabetes into four common subtypes, each with different causes. Here’s how smoking affects the risk:
- Severe Insulin-Resistant Diabetes (SIRD):
- Ever-smokers: 2 times higher risk
- Heavy smokers: 2.4 times higher risk
- SIRD is the most strongly linked to smoking, as it involves the body not responding well to insulin.
- Severe Insulin-Dependent Diabetes (SIDD):
- Ever-smokers: 20% higher risk
- Heavy smokers: 52% higher risk
- This subtype is caused by a lack of insulin.
- Mild Obesity-Related Diabetes (MOD):
- Ever-smokers: 29% higher risk
- Heavy smokers: 57% higher risk
- MOD is tied to excess body weight and unhealthy lifestyle habits.
- Mild Age-Related Diabetes (MARD):
- Ever-smokers: 27% higher risk
- Heavy smokers: 45% higher risk
- Common among older adults.
The researchers defined heavy smoking as smoking 20 cigarettes a day for at least 15 years.
Genetic Risk Makes It Worse
The study also found that genetics play a big role in how smoking affects diabetes risk. People with a genetic tendency toward poor insulin production were over three times more likely to develop SIRD if they smoked.
This suggests that people with a family history of diabetes should be extra careful and may need more help to quit smoking.
Why This Matters
Smoking doesn’t just affect the lungs and heart — it can directly harm the body’s ability to use insulin, leading to diabetes. According to the study, smoking may be responsible for over one-third of all insulin-resistant type 2 diabetes cases.
That’s a huge number, and it highlights the urgent need for stronger anti-smoking efforts, especially among people with a higher genetic risk.
Quit Smoking to Lower Your Risk
The key takeaway from the study is simple: Quitting smoking can reduce your chances of getting diabetes, no matter your age or weight.
As Emmy Keysendal pointed out, “Our findings emphasize the importance of smoking cessation in the prevention of type 2 diabetes. They also indicate that genetic information may help identify individuals most likely to benefit from extra support in stopping smoking.”
The research is still considered preliminary until it is published in a peer-reviewed journal, but the results offer strong evidence to support smoking cessation as a vital step in diabetes prevention.
