Smoking Tied to Increased Risk for Type 2 Diabetes

WEDNESDAY, Sept. 17, 2025 (HealthDay News) — Smoking increases the risk for type 2 diabetes across all disease subtypes, according to a study presented at the annual meeting of the European Association for the Study of Diabetes, held from Sept. 15 to 19 in Vienna.

Emmy Keysendal, from the Karolinska Institutet in Stockholm, and colleagues investigated whether the influence of smoking on diabetes risk varied by subtype and explored interaction with genetic susceptibility to diabetes, insulin resistance (IR), and insulin secretion (IS). The analysis included 3,325 people with incident type 2 diabetes (across two cohorts) and 3,897 controls.

The researchers found that ever versus never smokers had an increased risk for severe insulin-resistant diabetes (SIRD; relative risk [RR], 2.15). A weaker trend was seen for severe insulin-deficient diabetes (SIDD; RR, 1.20; 95 percent confidence interval [CI], 0.98 to 1.47), mild obesity-related diabetes (MOD; RR, 1.29; 95 percent CI, 1.06 to 1.57) and mild age-related diabetes (MARD; RR, 1.27; 95 percent CI, 1.12 to 1.44). Smoking accounted for a higher proportion of SIRD cases (35.3 percent) than for SIDD (13.1 percent), MOD (13.0 percent), and MARD (13.9 percent) subtypes. Across all subgroups, heavy smoking (≥15 pack-years versus never) was associated with a higher risk. There was an additive interaction between heavy smoking and type 2 diabetes genetic risk score (GRS) and impaired insulin secretion GRS, but not insulin resistance GRS, on the risk for both SIDD and SIRD. 

“Our findings emphasize the importance of smoking cessation in the prevention of type 2 diabetes,” Keysendal said in a statement. “They also indicate that genetic information may help identify individuals most likely to benefit from extra support in stopping smoking.”

Abstract

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