Smoking doubles the risk of severe diabetes: new research from Scandinavian scientists

Modern classification divides type 2 diabetes into four subtypes:

• SIRD — severe insulin-resistant diabetes;

• SIDD — severe insulin-deficient diabetes;

• MOD — mild obesity-related diabetes;

• MARD — mild age-related diabetes.

Researchers analyzed data from 3,325 patients with type 2 diabetes and nearly 3,900 controls from the Norwegian HUNT and Swedish ESTRID studies, with a follow-up period of up to 17 years.

The results showed that both current and former smoking increase the risk of all type 2 diabetes subtypes:

• For SIRD — the risk increased 2.15 times;

• For SIDD, MOD, and MARD — by 20%, 29%, and 27% respectively.

Heavy long-term smoking (one pack per day for 15 years or more) increased the risks even further: The likelihood of developing SIRD rose 2.35 times, and for the other subtypes — by 45–57%. The study also highlighted that the use of snus (smokeless tobacco) was associated with an increased risk of severe diabetes forms. People with genetic predisposition were especially vulnerable. Among heavy smokers with a high genetic risk of impaired insulin secretion, the likelihood of developing SIRD was more than 3.5 times higher compared to non-smokers. “This research clearly shows that smoking is a powerful risk factor not only for cancer and cardiovascular diseases but also for diabetes — and its most severe forms. People with a genetic predisposition are at particularly high risk. Quitting tobacco is one of the most effective preventive measures to significantly reduce the likelihood of disease,” says Gintautas-Juozas Kentra, physician and Deputy Chair of the National Association Densaulyq, expert in harm reduction. In Kazakhstan, according to the Bureau of National Statistics, in 2024 tobacco smokers accounted for 20.7% of the adult population (19.4% in 2023), including 39.8% of men and 7.6% of women.