Smoking Increases Risk of Type 2 Diabetes Regardless of Subtype — Study

A new study presented at the annual meeting of the European Association for the Study of Diabetes in Vienna has shown that smoking raises the risk of developing type 2 diabetes regardless of its subtype, Medical Xpress reports.

Researchers from Sweden, Norway, and Finland examined how smoking — both current and past — affects different subtypes of diabetes:

SIRD (severe insulin-resistant),

SIDD (severe insulin-deficient),

MOD (mild obesity-related),

MARD (mild age-related).

The study included about 3,325 people with type 2 diabetes and nearly 3,900 control participants, with long-term follow-up in Norway and Sweden (average duration — 17 years). The analysis showed that both current and former smokers had a higher risk of all four subtypes compared to never-smokers.

The greatest increase in risk was seen in **SIRD**: smokers were 2.15 times more likely to develop this subtype than non-smokers. For **SIDD, MOD, and MARD**, the risks were elevated by 20%, 29%, and 27% respectively.

Heavy smoking (e.g., 15 pack-years or more) further amplified the risk:

SIRD: 2.35 times higher risk,

SIDD, MOD, MARD: increases of 52%, 57%, and 45% respectively.

The study also found that the use of smokeless tobacco (snus), common in Scandinavia, was linked to higher risks of severe subtypes — especially SIDD and SIRD — compared with non-users.

Importantly, individuals with a genetic predisposition to type 2 diabetes, particularly to impaired insulin secretion, faced even greater risks if they smoked heavily. For example, heavy smoking combined with high genetic risk for poor insulin secretion raised the likelihood of developing SIRD more than 3.5-fold compared with people without these risk factors.

Conclusion: Smoking is a significant risk factor for all type 2 diabetes subtypes, but its strongest effect is seen in the severe insulin-resistant subtype. This underscores the importance of smoking cessation in diabetes prevention and highlights the potential of using genetic information to identify individuals who may need additional support to quit smoking.